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#868429 01/08/22 3:54 am
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I'm building a motor with a big bore kit recently purchased from a reputable dealer and am having some strange issues that may be attributed to mis-machining of the barrels.

The main symptom is that once the barrels are on the cases, and the cams' gears are tight, both inlet tappets hit the drive side lobe of the cam. Only the timing side tappet hits the timing side lobe.

After checking, double checking, triple checking all the variables i can think of, it really seems the inlet tappet block bore is off center.

The (new) tappet block is straight, measured to the outside of the barrel skirts with a straight edge off the tabs on the block.

New cam bushings. Everything fits well, with no gap under the shoulder of the bushing in the timing side case. The cams turn really nicely in the bushings with no binding.

With the inlet cam gear loosened .010" and the cam pushed to the drive side, the tappets move separately, with a bit of a scrape feeling through the tappets, but move completely independently at .015", with no scrape.

The inlet tappet block looks a bit off center in the fins, but everything fits on the case studs. I know the machining accuracy can't be judged on the casting, but still, it's off the same way that makes sense for the symptoms.

I had to machine the cases to fit the slightly larger barrel skirts, but that doesn't seem to be the issue as the barrels seem to fit fine on the studs. A bit snug, but goes on just fine with the barrels' holes centered on the studs.

Is there something I'm missing?

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Who made the big bore kit?

Maybe yours isn't the only one with he problem.

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You should be able to measure the centering of the tappet blocks to the inner stud holes, but note that the drive side holes in the barrel are slightly larger than the rest, as they mate up with the alignment sleeves on the studs. Anyway, the inlet and exhaust distances should be the same. The gap between the cam lobes should also be centred on the crankcase tappet holes.

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Yea. I'm hoping someone else has run into this and has a solution other than blindly trying another one...

It's an Aerco 750 kit.

The barrels have been somewhat disappointing. I had to shorten the shoulder on the exhaust tappet block because that side of the barrel flange is .020" thicker. The threads for the head bolts were very rough and needed to be chased to the point of needing a new bottoming tap. The cases needed to be bored out .030" for the barrel skirts.

Any of the things individually are not a big deal (and some, honestly, expected), but collectively are a real pain. If I didn't have a mill and lathe (and a surface plate and a lot of measuring tools), this rebuild would be all but completely impossible. A shop rebuild would be shockingly expensive with all the measuring and machine work.

This much massaging of a new part that is advertised as plug-and-play is worrisome. The bores are seemingly parallel to each other, and perpendicular to the base flange, so (so far) the basic function is correct, but I may be remeasuring everything very soon.

Other variables I didn't previously include are: new LH Harris cams check out ok (as far as journal and lobe placement - lobes even a bit narrower than stock Triumph), barrel base studs are square in the cases, breather disc and spring are correct (problem same with or without), stock reground tappets, new Kibblewhite tappet blocks, a straight edge across the faces of the inlet and exhaust gears lines up perfectly,

The cases were skimmed on my milling machine, but everything was surprisingly nice and square, and a minimum of material (.004" max depth cut) was removed. Most of the material removed was to square up a fore and aft discrepancy, not a side to side.

I really hope it's just something else I'm missing, or at worst, an out of tolerance part that snuck through.

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Yes. The tappet block bore is visibly off center from the casting, and when measured it's about .030" from center, between the nearest stud centers (taking into account the sleeve on one side). The cam lobes are not exactly centered between the case halves, but both are the same and the exhaust tappet blocks/cams have no issue.

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The tappet block should definitely be centred to the studs, so time to send the barrels back!

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Todd- I don't think I'm allowed to post photos here because I don't pay to be a "sponsor", but I will email you an engineering drawing of the cylinder and tappet block locations. There is a lot of stuff I don't sell at my shop because I know that I will be the final quality control and a lot of parts won't make it out the door. Check your email for the drawing. Hope it helps you, Dan

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Yea. That's what I'm afraid of.

Hopefully the supplier will waive the 30 day return window. It was gathering dust while the crank and pistons were at the crank shop getting rebalanced for 3 months.

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In the worst case, you are stuck with the barrels, the lifter bores can be relocated... It will be a project but you do have the tools.. Good luck..


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the tappets fit with just 0.015 camshaft relocation?

can you fit a shim behind the thrust surface of tbe timing side cam bearing , or will tbe cam pinion rub on thecase?

a 0.015 valve spring shim might solvethe problem.


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Or take a little off the tappet. Even saying that makes me cringe, though.

kevin #868528 01/09/22 2:01 am
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Well, yea. the tappets clear the other's lobe, but at approximately 10 rpm. I'm not sure I trust myself to come up with what I feel is safe for the motor (and rider) at 5k+ rpm with a shimmed cam/bearing. I really thought about the shim, and couldn't shake the thought of what happens next time someone goes in there and gets a DPO moment. I don't intend to necessarily own this motor forever.

I'm optimistic that the supplier and myself will come to an agreeable conclusion.

As Hillybilly bike mentioned, yep, I've got the tools should it come down to it. Thanks for the perspective and might actually be cheaper than redoing a bunch of work to the associated parts. Never done an interrupted cut on cast iron before. Hmm....

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Hi ingermanso, Sorry to hear about your woes.

Do you still have stock cylinder you could trial fit & see how it aligns. Then compare tappet block side to flange holes on both. If it's possible to determine cause of fault & photographing problem, it makes it a lot easier to return defective parts. Also the seller can forward photos to vender so show indeed it was not machined correctly.

On the other hand if old cylinder has same problem, you know it's not the Aerco cylinder.

I feel for you. Spare parts that actually fit are a huge problem for us owners. These bikes are very time consuming to work on & any sublet work often takes weeks to months. They seem especially busy during these covid days as owners have a bit more motivation to get the project bikes moving forward with lockdowns & all.
Don


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Probably not relevant, but I noted that you chased the barrel threads - you do know that they are BSCY 26 tpi, not 24 tpi UNF? I got caught out by that one in wanting to change to a stud fixing for the head instead of bolts a la T140.

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Yep. BSC. Thanks.

Gotta find a new bottoming tap. I was really afraid the tap was going to lock up and break off in the last hole!

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Well this is interesting as I just ordered an Aerco 750 BBK for my 70 TR6R, I have the same kit on my 1970 TR6C with Mega Cycle street/ Strip cams and did notice the thicker base flange which was corrected with a set of adjustable PRT's. I did not notice an alignment issue though with the tappet block bores or an issue with the piston clearance. I was already figuring the tappet block area will need some machining so this go around would not need the adjustable PRT's but now will double check the alignment as well.


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Originally Posted by TR7RVMan
I feel for you. Spare parts that actually fit are a huge problem for us owners. These bikes are very time consuming to work on & any sublet work often takes weeks to months. They seem especially busy during these covid days as owners have a bit more motivation to get the project bikes moving forward with lockdowns & all.
Don
Sublet? do you mean a repair business run out of your home garage? Just curious, how many bikes do you work on in a year? What work takes months, do you mean waiting for parts.....Lock downs? must be a totalitarian govt where you live, lol..


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He lives in California. Isn't that now a totalitarian government state?

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To get back to topic, it would be possible to machine the barrels for Thruxton tappet blocks, but that would mean different followers, cams etc. I have this stuff in my stock, but I'm on the wrong continent

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Blown Income, I had heard about piston clearance issues, so I checked that immediately as it came out of the box. Had good clearance. Checked barrel flatness; good, but it was .018" taller than stock. Didn't even think to check the tappet bore placement, since it seems like shooting fish in a barrel (as it were) to get that placement right, but here we are. The .020 discrepancy in barrel base thickness on one side was an annoyance, but no biggie.

TinkererToo, that's a great idea (!), but I don't have any of that stuff kicking around, and just spent a good deal of money already replacing it all. Would be cheaper at this point to make a new tappet block of bronze or iron, if I'm going to adapt something.

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Hi Irish Swede, California is where my Grandparents on both sides moved during the depression in search of work. It worked out good for all of us. Got good jobs & did ok. So I'm used to the political climate. Thing is our location means thousands a day pass through our state for lots of reasons. We have a very diverse population for lots of reasons. The state is very populated so there is easy transmission of any disease that is going around, locally or worldwide. So things are not so simply & many points of view. I'll just give some personal observation from my life where it's at today. Take it for that. My point of view.

Covid is very rear here. I personally have loved ones that perished after catching covid. None that died were vaccinated. I know several non vaccinated people in my greater social circle at church & in the ballroom dance community. Yes, I'm a dancing mechanic. Do country dancing also. We've danced from coast to coast. Too bad I've not had the Triumph out of state. Back to subject, Of all the unvaccinated we know, now all but 2 have gotten covid & several have died. There are now many break through cases of vaccinated friends we know. So far thank God none of the vaccinated have perished. The funeral home down the road from me is quite large. For many months they had refrigerated semi trailer for dead body storage in parking lot. If the diesel engine was running it was occupied. It ran 24/7 for some months. In these unique conditions what are the health regulators to do?? Let it go & have more deaths or lock things down & restrict our free movement. No easy answer is there? When you personally begin to see your loved ones pass & the disease run rampant through your community it changes things. The problem is there is no easy solution. On paper herd immunity is wonderful option. All that catch it will either die or gain immunity. With no vaccine & total freedom to not mask or do what you will indeed is total freedom. We certainly cherish freedom, that is never to be disputed, but sometimes in special times such as a pandemic is it responsible to voluntarily put our freedom & rights to side for the greater good of the nation & world's health?? Not easy is it. The rule makers are damned if they do, damned if they don't.

So back to bikes the lock down meant many were laid off, shortened hours, or working from home, giving more free time for hobbies such as Triumph Motorcycles. It certainly did me & I'm retired! All the dance halls were closed too you know. However motorcycle parts sellers & machine shops are considered essential businesses. So.... even our evil government knew we needed our bike parts during the pandemic!!

Sublet work is repairs, work on the bike you can't do yourself, so you have someone else do that work for you. Cylinder boring. Valve guides, cutting valves & seats, Paint work, etc. I can't do C630 guides or bore my own cylinders. I can't do professional paint job at home. Sublet work can be to some home mechanic like me, or to a real shop like machine shop or paint shop etc. So many bikes were brought out of storage the parts venders sold out, the distributors sold out, the manufactures fell behind on production. They have to be careful about expanding as after this unexpected demand is satisfied they will have to lay off the extra workers & cannot pay for the extra machines to make parts. Gets complicated doesn't it?

Funny how things have panned out in my area east of San Francisco. The businesses that restrict a client's freedom by demanding vaccination & mask wearing have become busy & successful. Patrons have learned vaccinations help, masks work. Do they really? I don't know? Numbers show that to be true, but in patron's minds it is true. They want to do what they feel is safe, so they go to businesses that make them feel safe. That's a very true reality in my area.

One thing that is totally undisputed.... West of the Sierra Nevada & south of the far north of state the weather is pretty darn nice! Allows for riding year round. Sure a little hot in the summer, you have to bundle up a bit in the winter, but sure beats watching TV. I spent the winter in Fort Lenardwood MO. In the Army. I got there the ground was frozen. Me too!! I didn't warm up until spring. Of course then a tornado came through. A few miles from us. We were safe. Next day went to survey the damage. Wow is all I can say. I was speechless. Maybe that's why the population in California is so big. The weather! Hardly ever humid here either. Everything is a trade off, that's for sure. Many points of view, that's for sure.

For sure, never any hard feelings!! Our binding connection is motorcycles. That's way bigger than politics.
Don


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Do you have a spare cylinder to trial fit?
Don


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I do. The old 650 barrel is at a worn +.060", so what to do? Jump to 750!

Spoke to someone at the dealer today on the phone. He quickly mentioned the 30 day return policy, but I'm having trouble imagining anyone being able to turn a complete engine rebuild with any farmed out work in a month. Hopefully it's a CYA scenario that can be overlooked when needed. I filled out an online return form and crossed my fingers. Still optimistic.

Worst that happens is I rebore the tappet block bore just oversized enough to get a centered circle, make and fit a steel top hat into the barrel, then refit the tappet block into the top hat. I'm a little worried about the recess that the shoulder of the tappet block nests into as it seems under the bottom fins. It would be a long bar in a boring head to be able to get in there to perform an interrupted cut. Chatter city...

Maybe a giant t-slot end mill? So many ways to ruin a brand new part!

The thing that has struck me lately is how much I miss my local shop that closed a few years ago. The Internet is not the same as your actual friends that work behind the counter smelling of old tires and exhaust, giving good reliable advice, and talking loads of [***] to your face when you ignore it. RIP Raber's.

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The law is very likely different in the USbut in UK, retailers sometimes try to hide behind limited time period guarantees such as 30 days etc, but they only get away with it with customers who aren't aware of their legal rights. Here, it is the law that goods sold by businesses have to be "fit for purpose" and "of reasonable quality". There is no set time limit on these requirements, though it is usually at least a year and can be a lot longer, depending on the item. In this country these laws come under the Consumer Rights Act. As I say, things may be very different where you are but if you aren't already absolutely sure, maybe it is it worth checking out?


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Sublet to me refers to property leasing and not necessarily services. As an electrician contractor I used the term sub contractor or subbed when I paid others to do excavating, setting power poles etc..Or Farming it out
Dancing? Yes, Rock and Roll 50's style. A Rockabilly steady beat and it's go cat go...
I live in a rural area, other than a mask requirement in certain places at certain times, it is business as usual
In the hot rod car world we called the installation of aftermarket parts as needing TLC, as in Torches, Levers and Crowbars
This is the reason my LSR bikes are made up mostly of modified stock parts.. But big bore kits have been around for a long time so there should be no problems..


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Hi Hillbilly, seton same page with sublet & TLC.
Not heard that definition of TLC before.
Isn’t that the truth!!
Don


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Originally Posted by t ingermanson
Worst that happens is I rebore the tappet block bore just oversized enough to get a centered circle, make and fit a steel top hat into the barrel, then refit the tappet block into the top hat.

You can use a Thruxton type guide block, they are larger in diameter:
https://www.morgo.co.uk/product/morgo-thruxton-tappet-block/

SR

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That's what I suggested earlier, but you would need the 3" radius followers, so cams as well to suit. The later (I think) followers had concave ends as well, so maybe new pushrods needed too. As it happens, I have all this stuff on the shelf, but of course I am in the UK! That said, you would end up with Thruxton valve train, so quite a performance lift.

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Hi Mick, sorry I didn't catch that. I'm not surprised you have it on stock! I have two 3" followers but no guide block. Morgos don't seem to have followers, but there must have been a few in use in the States back in the day I would think?

SR

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Bit of an update:

The distributor has said they will not honor a return of the defective part, due to the 30 day return window having closed. It seems an unreasonable expectation to be able to properly rebuild a motor with farmed out work in 30 days, but here we are.

They have offered to help facilitate a warranty claim to Aerco, but I'm not sure what that means. I get a very short email every couple days. The "returns dept" has no published phone number.

A warranty attempt is apparently made by me boxing (perhaps the entire kit, perhaps just the barrel) up the parts(s), and shipping them off, Aerco deciding whether or not it falls under warranty (dubious quality standards thus far displayed), hope for the best and expect the same barrel (or perhaps a worse one) to show back up.

Should I just take what I've got, apply Hillybilly's TLC, and let it go?

I'm feeling pretty taken advantage of by the distributor who got paid for the part (they are a sponsor of this forum, and I asked for no forum discount, hoping for no discounted service) and is passing the buck, rather than offering the service (I think) they have already been paid for.

For our overseas friends, there are little to no automatic consumer protections in the US. If I have a beef, I can sue them and see what happens. Probably nothing.

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We now know to be suspicious of the AERCO cylinder. I'll stay well clear of their products now.

Now, please advise us who is the "distributor.' Maybe his return policy dictates that we should avoid him as well.

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I'll flog you a virtually new morgo kit with blocks and followers for $600 AUD if you like. LOL.

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ingermanson, the boring of a larger hole, a plug and relocating the tappet block is a solution...but it will require some precision work from the base side of the cylinder block..But may create an annoying oil leak situation.Or take the challenge to machine a new larger OD tappet block to fit the situation, you have the skill to do it
Since you did some clean up work on the piece it may fall under the often used disclaimer no returns if item is modified
I suggest calling the Attorney General of the vendor's state... I had a situation of buying a used car out of state from a large car dealer in Maryland. There was a title issue not disclosed ...I called the Maryland AG and they got right on the dealer .
Good luck


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Think I'll drive to find a place, to be surly"
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@Hillbilly.
I've thought about trying to make an oversized tappet block. Might try that before I start hogging into the barrel. Trying cast iron would be relatively cheap, but the correct bronze is insanely expensive. $170 for 6" at a quick check. Yikes.

Doing a leaky sleeve would give me a chance to blame the *%$%^&* pushrod tubes!

Nothing's been done to the barrel yet other than installing junction blocks. I try to always modify the cheapest part to replace.

@Swede. I'm going to wait until it plays out before singing anyone's name. Once I've started down that road, there's only one destination, and I'd like to be fair to everyone.

@NickL.
Give me a minute. I might take you up on that...

Anyone want to buy an Aerco big bore kit? Never been run!

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Hi, Working in California in the automotive trade basically all my life. We had Bureau of Automotive repair training often. You had 30 day contract for returns. However.... Seeing the results of small claims court even a few years later.... You'd probably get refund. However, is it worth the time & effort?

Suppose you had photos and videos of the problem with new cly installed. Then you had photos & videos of old cyl & it works good. That makes a huge difference to sellers & manufactures. Truth be told do you know for 100% certain your cams are not centered properly? The photos & videos are proof of what's going on. Will only take you a few hours to remove pistons, tape up the rods, swap tappet blocks to old cyl & test.

You'll look like an idiot if the cylinder is not the true fault. Where does that leave seller? You must be real life sure with solid documentation. Then you have valid claim. I worked 11 months in warranty department. Been down this road many times. Solid documentation is everything. Then there is no dispute where fault lies. Only then can you reasonably seek a remedy.

Seller can't send cyl back on a hope & suggestion. They must have solid documentation. Without this documentation small claims court would deny your claim.

I'm 100% on your side. Been in your place. I just hate the replacement parts situation. Many (most??) spare parts are simply junk & poorly made. If the sellers have a workshop & actually repair bikes it goes along ways towards stocking better parts. Yet many times better parts are simply not made. NOS is long gone. Most parts sold as NOS is actually old Harris or the like. NOT genuine Triumph. I could go on for hours how frustrating it is to get proper fitting spares. Harris says made from original blue prints. Might be, but they still don't fit properly where the original Triumph part fits perfectly!!

What is parts seller to do?? They simply can't buy better parts, since none are made. If your tappet bore is indeed bored wrong it should be taken back by Aerco. They should have a warranty department to handle that. But do they?

I recently went through my transmission. Needed some gears, layshaft. Got new Harris parts. A crap shoot for quality. Tooth finish was marginal. Layshaft was not to dimensions of old & dogs would clip each other when not in gear. Had to custom make thrust washers to bias layshaft over to stop dogs from hitting. I can do that. What about the average Joe that doesn't have lathe. Who is he going to find to set this up? Took hours!

There is simply no excuse for the poor quality of spare parts. If the parts actually fit & were as durable as genuine twice the price would be a good value.

Might be better to buy Morgo kit & grind the fins round? This entire situation you're in just sucks!!
Don


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I would not touch the barrel my self or get anyone to work on it. Why should you ? Its brand new and you have a expectation that the goods you bought, not inexpensively, will actually fit and be of good quality.

Forget about the 30 warranty nonsense, go back to the seller and tell them they sold you dud barrels, and if they want to get all legal, say fine, the small claims court it is then.

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Meanwhile, the OP has to wait for his small courts claim date...and even if he wins, there is no guarantee of payment, it's his problem to collect it..And being mail order the claim may have to be filed in the vendor's district that could be in another state...


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I assume you used a credit card to pay for the cylinder. Most credit card companies will help with these types of problems. PayPal has terms that handle situations like this.

I must disclose that we are one of several distributors who supply Aerco cylinders to dealers in the US.

I have some problems following this thread: When facing the crankcase mouth, you level the front to back before you take a cut to level. If leveled properly where the face was level side to side you would never have to take ANY from the mouth front to back. When mounting the crankcase in a fixture, referencing the main bearings, you are leveling the crankcase front to back to establish a datum point. Then you can check the crankcase face to see if it aligns with the center line of the crankshaft.

I can only assume that you are working on a non-unit motor as the the Aerco is a drop on kit requiring no machine work to install. If you are working with a Unit motor, and having to bore out the crankcase .030" to install the cylinder, raises some flags.

Quote
"The cases needed to be bored out .030" for the barrel skirts. "

The castings are machined on a CNC machine. The bore, outside face of the skirts, flange face, and all of the stud and oil feed holes are machined while in a static fixture. This means that any metal that has to be removed from the crankcase is a problem with the crankcase, not the cylinder.

Seeing you have access to someone that has a Bridgeport mill you can easily measure the location of the tappet guide hole in the cylinder flange between the the studs. If he has a digital readout (DRO) it should only take a half hour at most.

I think you mentioned somewhere above that the cam lobes are not centered in the hole for the tappet guide in the crankcase. This is strange.

As I have a 100% return policy with my dealers I don't think the unit came through me.
Feel free to PM me.
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First off, thanks everybody. For both good advisement, and for the interest helping me out.

TR7RVMan, there is no doubt a fault with the barrels. One picture is all you'd need to see. I don't have the ability to post pics, but perhaps I'll up my membership again so I can. I've checked everything that i can think of a few times, and everything else seems to be a ok.

John Healy, The (non-unit) cases were mismatched as the previous pair cracked across the drive-side bearing mouth. The "new" pair needed to be leveled, and there was a small but definite low spot on one of the corners. Don't know what happened, but at some point it got a bit squished, but only .003 lower than the rest of that side, and just that corner. The Starrett "Last Word" dropped off on that corner traveling across both axes. Much better than I thought I would find. I skimmed the entirety of the mouth until I got light witness marks at the low spot. The cut at it's deepest point was .004". The opposite side case was lower than the other's high point, so it fit right into those cuts. It got got maybe .001-.002" removed. With the crank and cams in new bearings and bushes, the seam between the cases before was barely enough to catch a fingernail, but I was worried about that low spot under the corner stud. The machining was done locating the crank on v-blocks, and leveling using 123 blocks and feeler gauges against the bottom sump plate surface until the mouth was as square as I could get it, dragging that Last Word across the face. 3 hours of set-up for a 5 minute op, as usual.

The cab lobes are not exactly centered, but only upon close inspection and measurement, once the tappets were not riding on their prespective lobes. If I wasn't measuring and was looking down the bores and comparing to the case seam, I'd say, "Yep. Centered."

There is one of the tappet block bores (inlet side) that is visually way off center between the studs (accounting for the locating sleeve around the one), the other (exhaust) is dead center. Measured, the "bad" one is .030" off center, with the set screw and counterbore being centered over the tappet block bore, not between the studs. The counterbore relief runs out of the barrel's flange lobe, so is more of a C shape than an O. (A Google search of Aerco big bore kits show barrels with this "feature" on a couple pics advertising their sale.) I don't necessarily think too much of that, because you can't judge these locations based on the external dimensions, unless the starting reference and registration point is known. Having an oversized casting would be the way I would approach it if I were making these.

I thought that perhaps the flanges on the new timing side cam bushings were too thick, offsetting both cams to the timing side, contributing the lobes being slightly off center and the one inlet cam hitting both tappets, but the flanges are the same as the old ones I pulled out. Could be that all four are too thick, but that might be stretching.

I guess the gist of this whole thing is do I look at these aftermarket parts as raw materials and expect to massage everything to get it to work, or is it a reasonable expectation that everything I pull out of the box is ready to plug and play. I'm ok with the former. I enjoy problem solving and playing with metal (I am a self-employed metal fabricator), but I don't have a good frame of reference for those expectations. Up until a few years ago, I had a local shop (or two or three) where I could go and get good parts and advice. If the repop parts were not worth the trouble, I would be told to go upstairs and pull a good one out of the used bins. All those folks have retired and I miss my ignorance!

All I really need from the supplier in question is this frame of reference. I don't have to like the answer, but I need the answer, instead of the wishy-washy buck passing. I have tried to make this clear, but...

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Could you have a new tappet block made with offset holes tor the tappets? Or perhaps re-machine your tappet block?




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I don't think there's enough room in the push rod tube for an eccentric tappet block.

If that was the road I traveled down, I'd make a new tappet block and fit to an oversize bore, or a sleeve to use the stock block in an oversize bore.

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Aerco stuff is normally pretty good.

Doesn’t help but uk law/ EU says the vendor is responsible.
They then take it up with the trade supplier.
As suggested if you paid by card then technically the card company is the seller.

It’s tricky because once you have machined something it’s complicated.

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As of right now, zero modifications have been performed to the part in question, short of knocking in tappet blocks.

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Originally Posted by Hillbilly bike
Meanwhile, the OP has to wait for his small courts claim date...and even if he wins, there is no guarantee of payment, it's his problem to collect it..And being mail order the claim may have to be filed in the vendor's district that could be in another state...


Oh i find the mere threat of court can work wonders. A summons to court on official paper can suddenly reopen negotiations. Worked for me on two occasions. A neighbour bought a cooker that would not work after a few weeks. The shop didn't want to know. So he made up a placard saying "This company are crooks, don't buy here" or something similar and spent a morning marching up and down outside their shop, and surprise surprise, a new cooker was suddenly offered.

Why should the OP spend his own money, time and effort and probably wind up with a bodged set of barrels anyway, when he paid for an article that should be a drop on item.

Someone might like to shoot Aerco an email telling them this thread is open on one of, if not the biggest, British classic bike forums on the web ?

I need a set of 750 barrels and was considering aerco because i find morgo barrels an ugly shape. I am having second thoughts, how many more ?

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Well, before we get the pitchforks out, I'm going to try and close all the tolerance gaps I can, starting with some new cam bushings. The lobes are not perfectly centered on the case seam. They are pretty close, but not perfect.

I'm going to try to go through everything individually and collectively one more time and get everything perfect (as I can) to rule out a tolerance stack. Everything can be "passing", but when all the tolerances stack up, it can push the assembly into non-functioning territory. I'm definitely in non-functioning territory, but which route got me here? I should know all of this before I make any decision, whether that's sending something back, or modifying to make it work.

I'll keep y'all posted.

Thanks again for all the help with this.

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Originally Posted by t ingermanson
Well, before we get the pitchforks out, I'm going to try and close all the tolerance gaps I can, starting with some new cam bushings. The lobes are not perfectly centered on the case seam. They are pretty close, but not perfect.

I'm going to try to go through everything individually and collectively one more time and get everything perfect (as I can) to rule out a tolerance stack. Everything can be "passing", but when all the tolerances stack up, it can push the assembly into non-functioning territory. I'm definitely in non-functioning territory, but which route got me here? I should know all of this before I make any decision, whether that's sending something back, or modifying to make it work.

I'll keep y'all posted.

Thanks again for all the help with this.



Any chance of a picture of the offending item ?

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I thought you said, some time previously, that you could see that the tappet block bore on one side was nit central? Didn't you even give a measurement (.030"?) for how far it is out? Surely that's your answer right there? Or am I missing something?


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Hi, Than was my point in fitting tappet blocks in original cylinders & trial fit them.

You had a known good condition as far as tappet/cam interference is concerned.
If not good you know you have to correct this first.
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If you PM me some pictures I can post them for you.


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Sorry Folks was a bit late getting the pics up, here are the pics of Tod's cylinders.

Jeez, looks terrible to me.

[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]


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These pics do look bad but also do not tell you the full story.

The thing with castings is the outer surface can be and are all over the place, so the tappet block can look well off centre but as long as all the other machined surfaces are equally 'off' then the relative parts will all line up.

A casting has extra material to allow for shrinkage and release tapers so you can get it out of the mould, the very first machining operation sets the datum surface that all other machining operations reference back to. If this first datum cut is off from some arbitrary outer surface on the casting then it will look odd but still function.

So in this case the tappet block should be central to the 2 stud holes and the 2 bores, it looks to be a lot more central to these than the casting outer surface, only measurement using DRO on a milling table will tell you the real offset, if any, between the tapper block bore and the other machined holes etc.

That the case halves are unmatched is another potential issue that will cloud the issue.

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tlooks that way to me too. he casting web on the inner side of each stud hole looks like the casting itself was loc a ted off center when they were drilled.

the tappet block is offset in the same direction as the stud holes. by the same amount? i dont know. where is the tappet block positioned with respect to the liners? as kommando says, the machining may be correct, just not aligned with a crude casting.

the original problem was that the tappets hit the cam lobes. what could be causing that other than the tappet block position?


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Originally Posted by BigBars
[Linked Image from i.imgur.com]
I don't know it this has been covered already, but if you use the stud holes as a reference for measuring the guide block location, you need to obeserve that the drive side hole is bigger to accomodate the locating dowel.
Sorry if I'm stating something obvious, or it has already been discussed!

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Damn if I wouldn't find some original 650 jugs...


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Hi slofut, What do you mean? Get genuine Triumph 650 jugs & recondition them? I agree 100% with that. I'm so disappointed with the lack of quality control of aftermarket parts.

A huge problem is finding suitable used parts. These bikes have been around so long, most rebore able used cylinders are on a running bike or in someone's private stash. The stash if often passed to friends when owner dies. If we are lucky, they go to ebay. Sure is hard to evaluate used parts from ebay photos. I've had to send many back.

It getting to be a hard road for those than want to build a real rider that is durable & can do the miles. If you just ride to the coffee shop 5 miles away on a sunny day, so long as it moves, it doesn't matter. But if you want to actually ride, this becomes a huge issue.

There is no easy solution when rebuildable used parts can't be found & new repro parts are luck of the draw. End user becomes a double looser when they have to start over & take the loss of earlier purchase. I've been there many times myself. Makes my blood boil every time I think about it.
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ive had excellent results with two sets of aerco 649cc cylinders on my race bike. fit well, broke in well, went faster than stink.

but that was not a bigbore kit.


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Originally Posted by TR7RVMan
Hi slofut, What do you mean? Get genuine Triumph 650 jugs & recondition them? I agree 100% with that. I'm so disappointed with the lack of quality control of aftermarket parts.

A huge problem is finding suitable used parts. These bikes have been around so long, most rebore able used cylinders are on a running bike or in someone's private stash. The stash if often passed to friends when owner dies. If we are lucky, they go to ebay. Sure is hard to evaluate used parts from ebay photos. I've had to send many back.

It getting to be a hard road for those than want to build a real rider that is durable & can do the miles. If you just ride to the coffee shop 5 miles away on a sunny day, so long as it moves, it doesn't matter. But if you want to actually ride, this becomes a huge issue.

There is no easy solution when rebuildable used parts can't be found & new repro parts are luck of the draw. End user becomes a double looser when they have to start over & take the loss of earlier purchase. I've been there many times myself. Makes my blood boil every time I think about it.
Don
Ouch.
I confess to have collected a few barrels over the years, not to mention cylinder heads. They followed me home, honest! I got them from here and there, as part of job lots and as discarded items with bikes I've bought. I do restore them though, I have several that can be rebored, and some that need new liners (I have 4), but all (if spring comes and I'm still alive, as my uncle used to say) will be used by me or sold on. Similarly the cylinder heads will be refurbished and either used by me or sold on. In my defense, these are other people's scrap, which I intend to restore and recirculate.
I have lots of cases and cranks too...
But I don't believe in hoarding, honest!

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THIS A LONG ONE!!
kommando,

I totally agree, and I think I alluded to that in my previous post. I went a step further and tried to eliminate the non-locating 3/8" stud, since as long as it fits in the barrel base hole, it has zero bearing on locating the tappets over the cam. I'm relatively comfortable using the two sleeved locating studs as the most reliable datum for the location of the barrels, as designed. In these PreUnit cases, I also had to bore them out to fit the larger barrel skirts. This wasn't advertised as necessary, but it is on PreUnit cases. I bored the cases to +.030", finding the center first and using a boring head, to give myself .010" bigger ID over the skirts' OD. When offering the barrels to the cases, the drive side skirt leaves rubbing marks inside the case bore, but everything fits fine with a couple bare handed smacks when the cases are bolted tight together.

I will say however, the exhaust side tappet bore is centered on the barrel base's lobe, visually and measured. It appears the side of the timing side barrel base has been machined flat, and that might be the locating face for all the finish machining.

So, I got a window of free time to replace the cam bushings. As a reminder, the bushings that were in there were replaced by me, but were from a rebuild of another motor years ago that never got used. I don't remember where they came from and had no packaging anymore. I honestly didn't inspect the cases as carefully as I should have either. It's hard to remember all the things to look at that have a bearing on the complete motor.

I tried to get two pairs of cam bushings made by different manufacturers to try and get as many data points as is reasonable, since I don't have a drawing or specs of the bushing. Turns out the bushing sets were both made by LH Harris. Oh well. There goes my vast data point acquisition! I measured them as carefully as I could and there was a bit of variation, both in overall length and in flange depth (on the timing side). The flange depth was pretty hard to measure, since there is a chamfer on top and bottom and the OD is only slightly bigger than the OD of the bushing. There seemed to be a variation from .095" to .099". As I said, it was hard to measure accurately with the tools I've got, with a regular caliper being best. I wrote in marker on each of the bushings the corresponding flange depth.

I heated up the cases and knocked the existing bushings out. I measured those and they were both the thinnest flanges in the bunch at .091 and .092". Looking into the inside of the case's bushing flange counterbore, it looked like they had been "cleaned up" or deburred, meaning it looked like the corner from the counterbore into the bore was less than square, which is not great news normally, but great news to me in that if the bushing with a thin flange was sitting deeper into the counter bore, it would cause the cam to locate with a timing-side bias, which is what I'm experiencing. Measuring the actual counterbore depth was all but impossible due the lack of access in the tunnel, and the texture of the inner face of the case, so I just marked it as "deeper" in my mind. The inlet side looked deeper/more molested than the exhaust.

Reheated the cases, and knocked in new bushings, just until the sound changed, and not a touch of the hammer more, using the ones with the deepest flanges in the bunch on the timing side. Reamed 'em out, put the cams in, tightened up the cam gears, and measured the center of the cam lobes in relation to the center of the tappet block bore of the cases and case seams. Dead nuts. Sweet.

I offered up the barrels to the crank-less bottom end, with the tappet block and tappets installed, and the tappets moved independently on the cam lobes! Sweet. With a possible bias to the drive side now, it's tough to check, since a loosened gear will only shift to the drive side (and not further to the timing side), but the inside tappet faces were about .026" apart, so if you move the cam to the drive side by loosening the gear a certain amount, you can extrapolate where it sits when the timing side lobe hits the drive side tappet. Once again, the inlet and exhaust lobes weren't hitting the tappets in the computed dead center (or inlet and exhaust same as each other) but both had enough wiggle room for me to feel comfortable that they were close enough, especially with thinner cam lobes buying extra wiggle room on the stock width tappets. I agree the math doesn't quite all add up from what wasn't working to what now seems to be working, but once again, there may be more at play than I'm seeing.

I'm going to run it and see what happens as the dealer has not followed up within a week of my last question of their offer to "walk me through" the warranty protocol directly with Aerco, and moreover, the tappet block bore could very well be within spec and I'll just waste a bunch of time and money being told that it is. I'm going to give another shout over to the dealer and see what their thoughts are. They have not been helpful in any way, so I don't have much faith in them and will not be patronizing them again. John Healey, who imports these reached out and said that in his experience these kits are good and that he would honor any return of defective merchandise outside of any "return window" purchased from him, but that the dealer in question had probably not bought this kit through him. If I were to buy one of these kits again (or anything Triumph aftermarket), I would make sure to choose the vendor carefully.

As far as my experience with the Aerco kit goes, it's more obvious to me now that the tolerance stack can be a real obstacle. The locating studs for the barrel are on the opposite case half (and are oriented perpendicular), as the locating point for the cam. The Aerco barrel seemingly uses a flat, machined on the timing side of the casting, to then drill and bore all the holes that use the opposite case half as it's locating point. With those complicating factors it sets things up to be off a bit, but the tolerances seem to be loose enough where it may not matter, particularly when Triumph was doing all it's own manufacturing and could keep track of all the minutia. When separate parts are machined to loose tolerances (even when those parts are individually within spec) by different vendors throughout the world, there are chances things won't line up.

The Aerco kit I got seems to be within the acceptable limits to make it work with other parts in the acceptable limits, with a keen eye on variables. I think there was a bit of a "perfect storm" going on here that had conspired against me. That's life...

One problem I also ran into was also due to the drilling of the studs within the off-center casting. Some of the stud holes were extremely close to the barrel wall, so I had to grind down a wrench very thin (!) to tighten the nuts. Yes, they are the proper 12 point, small-head nuts. The drive side stud closest to the inlet tappet block was the closest to the wall, and the wrench had to go down to a .045" (!) thick wall in order to get the wrench on the nut. With the magneto on, that's going to be a rough one.

The difference in thickness of the barrel base flange at the tappet block bore is still very much "a thing" and has resulted in the needed modification of the tappet blocks and pushrod tubes in order to get the proper crush on the seals. If you've got some good measuring tools, the tappet block setting tool, a lathe, a tiny adjustable reamer for the tappet blocks, and a boatload of pushrod tube seals, then it only takes a few hours. Easy peasy, right?

The barrels are .018" taller than a stock 650. Don't know if the pistons are a corresponding amount taller, or if the compression ratio is something that falls where it falls based on various parts.

I've timed the cams' centers to 99.5 inlet and 102.5 exhaust (supposedly for less ethanol ping and more mid range torque -- it's a big bore 750, right?) and going to give it a go.

Your results may vary.

That's my current story, and I'm sticking to it (until I'm proven wrong and then I'll change my story to meet your better facts! HA!).

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Posts: 585
Likes: 62
I'd hazard a guess that the machining fixture of the Aerco manufacturer locates most of the machining operations together, and depends on where the rough casting sits in the fixture. Given that this is a fairly rough sand casting, I can easily see why the casting could be "off" to the machining, I guess you have got one of the more extreme ones. As well as the Aerco, I use T140 barrels (for a 10 stud setup) in pre-unit engines, and you have to remove still more from the crankcase mouths as well as removing most ot the lugs in the crankcase mouth (none of the "essential" screws). I am not sure that the spigot holes and the tappet block holes in the cases are particularly accurate in the original crankcases, as they only need to be clearance.
Glad you are on the way!

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