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Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #724974
02/10/18 5:37 am
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If you have a printing supply company near they may be able to supply toluene, it was/is used on gravure or intaglio printing as the main solvent.

Very low flashpoint, high volatility substance. Everything had to be zener barrier-ed intrinsically safe Namur style.


That epoxy is yankee so it should be fine with ethanol fuel. The name is Manley Performance not Manly as i spelt it. I think they will sell direct.

Last edited by NickL; 02/10/18 5:58 am.


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Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725011
02/10/18 12:37 pm
02/10/18 12:37 pm
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argyll. scotland, uk
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Great info Nick, there is a printer in Oban, will see if they have toluene, pondering whether to drill up into the floor of the ports and fit a small self tapper to give a peg for the filler to hold onto. Will go for the manley stuff, thanks. Head has to come off, oh well, cest la guerre. will make extracting the motor a bit easier. Also wondering if the vanished filler has anything to do with the increased exhaust tappet clearance, curious to see what the piston top and chambers are like, comp is still good.
250 mls Toluene ,£ 6.99 eBay, sorted.

The triumph board clutch pull thread got me thinking, will mod the clutch lever pivot distance, plug existing pivot, re-drill and bush to 7/8" centres , should give a lighter pull than the current 1.125 " pivot centre.

Last edited by gavin eisler; 02/10/18 1:12 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725133
02/11/18 3:35 am
02/11/18 3:35 am
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Posts: 768
Brisbane, Australia
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Hi gavi,

Good to see this active again. Couldn't post for a couple of days because of instant log-out issues on my other computer.

Re JB Weld, I used Manley Magic seal the same as in this eBay listing which is what Nick is recommending.

http://www.eBay.com.au/itm/MANLEY-4...-Manifolds-1-2-lb-Part-A-1-/321918742913

Only been 2 months so no extensive long-term testing. I think remodelling around the guides and doing the bowl is the hard part so re-filling the port floor is likely not onerous. I found the Manley stuff has a different texture to JB when set and easy to shape/grind. I used a rotary file bit in the drill. Also, it has the advantage of being like clay and can be shaped quite close to what you finally want – doesn’t run like JB does.

Only been 2 months, but have fitted new AMAL Premiers (still fiddling so no final updates yet), but white epoxy had turned brown, but otherwise looked OK.

The high temp material I used was Aremco Pyro Putty but I think Manley do a high temp one as Nick says.

Cheers
Ray


BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725139
02/11/18 4:25 am
02/11/18 4:25 am
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Cheers Brizzo, Manley stuff is in the post , clutch stuff ongoing ( Clutch was OK just , interested in making it better), rifled through old stock, got 6 flat steel plates@ 0.075" each and 6 surflex @ ~0.144 " frictions to be ID reduced and bought some 1mm cork for the 6.5 clutch mod , measured the stack height and it should fit . Shopping list includes new push rod. Stack height of new clutch is not far from as fitted even with an extra plane plate and 40 thou cork, the new steels fitted at present were 80 thou plus .
next installment will be head off ,motor out. Chassis to welders, fiddly stuff at home. Nichts are drawing out, better get on wi it. April deadline.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725154
02/11/18 9:22 am
02/11/18 9:22 am
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The 6 and a half plate mod is for misers who don't buy new pushrods. We saw them in half and put a ball bearing between the halves.

Don't know if it's good thing or bad, but my cork plates are full radial depth: one solid ring of cork on each friction face. I just placed the plate on the cork sheet and marked round it, inside and out. Then cut the cork to be inside the lines.


Amateur Loctite enthusiast.
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725155
02/11/18 9:42 am
02/11/18 9:42 am
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Unlined drum and a plate just been pressed onto the glued cork.
[Linked Image]

Lined drum and a plate with old lining not yet picked off.
[Linked Image]

The drum wouldn’t hold much more!
[Linked Image]

Yes, it’s a Tony Hayward belt drive. Uses most of the Triumph clutch, with an alloy drum and modified driving plates.


Amateur Loctite enthusiast.
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725183
02/11/18 1:45 pm
02/11/18 1:45 pm
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argyll. scotland, uk
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Thanks TT, I fitted a Hayward belt drive to my NorBSA , IIRC the centre roller track was too tight and needed fettling to run properly, I have hardly used it so no real experience, . Been checking the old plates it seems that the old Surflex friction plates are warped, hard to tell if its uneven wear or not but they all fail a 2 thou feeler test, when stacked there is noticeable spring, once the clutch is apart will probably use the existing friction plates , i know they are OK, . The triplex clutch drums have a lot of big holes in the back so I wont be able to fit a continuous ring of cork.
Please correct if I am wrong, I plan on adding 1 mm of cork to the back of the drum, then one extra plain steel, followed by friction , p, f,p,f,p , f, p,f ,p,f p.. last plain gets 4 bent tangs so it wont fall off. Total 6 friction , 7 plain, the stack ends up thicker by one plain at 0.075" and 1mm ( (0.040") of cork, so 0.105" . or am I missing something? it looks like you fitted a half friction plate first instead of gluing cork to the drum, is this because the plain steels wont go in far enough on the centre hub, I dont have one handy to check.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725196
02/11/18 4:07 pm
02/11/18 4:07 pm
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Iowa
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Do you run oil with the Hayward belt drive ? Looks like it uses the stock bearing hub.


1968 BSA Firebird
1200 HD
XS 1100
1972 Rickman 125
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725199
02/11/18 4:29 pm
02/11/18 4:29 pm
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They're not very good photos.

I glued cork to the back of the drum. No half-lined plate.

The original Triumph setup had a fully lined plate in first. One lined face sat idly against the drum, because driving plates turn with the drum. You're effectively putting a plain plate and a layer of cork underneath that first fully lined plate. You then get the benefit of two more friction surfaces.

You end up with 6 fully lined plates, 7 plain plates and the layer of cork glued to the drum. The outer steel plate needs some ears bent in to catch the splines. I think I did four. Maybe two would be enough.

I ran out of cork gasket material after a couple of plates and bought hobbyists' cork mat 1/32" thick, from Amazon. The mat is pretty fragile, but Evo-stiking it to the steel plates holds it together. Not completely sure how it would hold up if narrowed like the modern plates.

My drum wasn't deep enough for the 13 layers of cork, so a couple of plates still have Surflex lining.


Amateur Loctite enthusiast.
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: konon] #725200
02/11/18 4:32 pm
02/11/18 4:32 pm
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Originally Posted by konon
Do you run oil with the Hayward belt drive ? Looks like it uses the stock bearing hub.



I use a standard Triumph Pre-unit primary case. I don't add any oil, but some oil gets into it.

Yes, it uses the loose rollers.


Amateur Loctite enthusiast.
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725207
02/11/18 5:37 pm
02/11/18 5:37 pm
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thanks again TT, I get it now. Messing around more with the stack, not a lot of room,! Most of the friction plates from the loft fail the feeler check, even the passed the feeler test plains must have some minor warp, when I stack them together and measure the total thickness its about 30 thou more than the sum of the parts, dug out the HCl , will see if the etching removes some of this error, a few are a bit rusty from poor storage. I know the fitted clutch plates are in decent condition, I also know theres no way another 120 thou of cork and plain plate will fit in, hmm, if the junk stuff from the loft doesnt square up I may spring for the 7 plate conversion.
30 years ago i was able to get 7 plates in, but all that stuff was well worn and it made little or no difference, cush drive was badly worn so it had no chance. .Snowing at the mo so that can wait. Each plain steel is getting a 20 minute dip in the HCl, outdoor job, , Risk assessment, avoid drunkenness and nudity, rubber gloves and goggles are probably a good idea.

Back to the head, looking for the source of tappet noise.
As found, DS Exh 3 thou, TS exh 3 thou, DS Inlet, 5 thou, TS inlet 1
Tappet noise was worse when cold, last time I did them I erred on the loose side of Zero, nothing too grim , although the 5 thou inlet may mean some rocker pad wear, will get a proper look soon.
Checked the Inlet rockers end float, this seems to be the likely culprit, DS 8 thou, TS 10 thou, this should be more like 3 , will get better spacers/ shims for the rebuild or just use thackerays, probably easier..
The exhaust rockers still have the thackeray washers, nothing to see here.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725248
02/11/18 10:18 pm
02/11/18 10:18 pm
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argyll. scotland, uk
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The head is off, note to self, checked head bolt torques before stripping , inner DS front took 1/4 turn to come up to full torque, the rest were all fine, might explain the oil lying on the front top fin, not a lot , but obviously from the front drains.

My concerns over the inlet rocker pad wear were validated, the DS pad which checked out at 5 thou before stripping is obviously worn, so stock rockers are going back in with thackerays,, the exhaust valve tips are showing signs of dimpling from the stock adjuster tips, inlets look dead smooth. There is no evidence of epoxy in the chambers, not thick carbon either, seems to have been running fairly cool, no white on the exhaust valves, piston crowns still show some alloy at the inlet cutouts, carbon on piston tops is mostly matt grey with no thick black stuff, no signs of mice. Both pistons have lighter carbon on the other side from the spark plug, centre to exhaust cut outs

Will take pics. head gasket is clean copper apart from two spots, lightly discoloured at the narrow centre bridge in front of the centre bolt hole, and lightly discoloured front DS , beside where I found the slack head bolt. Need to up my re-torquing regime. I think last go round was at 1,000 miles, it did another 3,000 after that. Will recheck at 2,000 next time.

Last edited by gavin eisler; 02/13/18 2:53 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725381
02/13/18 12:25 am
02/13/18 12:25 am
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You may find the large radius Hayward style mushroom tappet screws/adjusters stop the valve end pitting.
They also have a hex adjustment so are easier to set.
As most of my racing valves were modified ones i used lash-caps which overcame the problem as well.
Some people say to set the adjuster dead centre of the valve, i tended to offset it a few thou to promote rotation.
Probably a waste of time but it made me feel better......... The thackary's are fine if you are not searching for the
last 0.002HP at 8000RPM. or using a radical cam.

I always thought everyone cut the clutch pushrod in half and put a ball bearing in then ground it to suit, this
normally improves the clutch action on it's own. Not really required if you are using an SRM end plate though.
I tend to live with slightly heavier clutches as i hate the bloody things slipping and it seems like every time i
have tried lighter operation set ups, 3rd gear acceleration is the give away and the damn things slip.

Try a set of allen bolts for the centre ones, they are normally grade 12 and will give the least stretch.
So many bolts around now are of dubious quality and are like cheese.
The use of large thick washers with them is also a must.



Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725396
02/13/18 2:48 am
02/13/18 2:48 am
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argyll. scotland, uk
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Cheers Nick will look for the mushroom adjusters, getting added to the list.

The clutch has been OK so far, it did need another 1/2 turn or so on the springs , like you say 3rd was the tell, there doesnt seem to be room for the 6.5 plate mod , the alloy pressure plate is thicker than the steel type, so i am going to etch the plain plates and call it OK for now.

Spent some time on the barrel fastener threads, the bolt I found a little slack had distorted female threads and test fitting of the bolt it was not as free as it should be, i think it was maybe under torqued due to tight threads, cleaned up fine with a tap.
The bolts John supplied are good quality HT allen bolts, with chunky washers , no probs there.

Some good stuff came in the post, now have matching rubber lever covers for the brake and clutch.
The Inside Story about Umberslade , diverted me for an hour or so, interesting , also slightly depressing, ,1200 mods to the P39 frame which was a less than blatant rip off of a Sonic Weld trackmaster , and they still got the seat height wrong!, the wide seat was a styling exercise , testers modded it straight away and got hell for it. Weird.

On eBay , bought a pair of 32 mm flat slide OKOs, , ridiculously cheap £30 each, stripped one today, was blown away by the quality, lovely chromed heavy slide, presumably brass underneath , too heavy for alloy, , couldnt fault it when stripped,spotless inside, all fits together great, needle has 5 notches, comes with 2 extra slow running and Main Jets for fiddling with,also has a power jet , extra bleed into roof of carb ,each carb comes with a neat mounting rubber( although the rubber has in ID of 28 mm, doesnt seem right, its possibly a one size for a range)) and spare jets, my only issue is that the jets are unmarked, will need to figure out sizes with plug gauges, the carb to motor will fit my existing stub , but the carb diameter at the mouth is about 55 mm, and the existing rubber to airbox is about 47 mm OD, , may be able to make an adaptor. Dimensionally they will work, tidy bit of kit, nice touches like an O ring for the real metal float bowl drain, I dont know how they can make them for the price. Makes an AMAL conc look like a lawn mower carb, time will tell if 32mm is the right size, the slide cutaway is not tunable , if the slide is too rich , fit a bigger carb, if too lean fit a smaller one.
The packaging made me laugh.
""OKO, new yuppie fashion trend, the best choice for your motorcycle" "delicate motorcycle engine". made in Taiwan. Who does the advertising bollocks ?

Last edited by gavin eisler; 02/13/18 2:50 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725398
02/13/18 3:31 am
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With that 370cc cylinder capacity my own choice for the road would be 30mm, they will be optimum for around 5,800rpm.
The same cylinder needs about 40mm optimum for 8,000rpm. About 45mm optimum for 10,000rpm. It's all about revs.
As you know i'm not a fan of huge carbs. Maybe my charts etc are old hat but i knew a lot of blokes who fitted big carbs
and took 'em off again........


I forgot John supplied the head bolts, it's just that i've seen a load of crap about and thought it worth mentioning.

Last edited by NickL; 02/13/18 3:41 am.


Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725420
02/13/18 10:56 am
02/13/18 10:56 am
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Good point about the carb sizes, I have had the 30 mm Mk1s for years, always been pleased with the low to mid range performance, the 32 mm OKOs were bought on a whim, might trial them for science sake , if i run out of things to mess around with ( unlikely!.)


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725490
02/13/18 9:55 pm
02/13/18 9:55 pm
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Pics of head gasket combustion chamber and stuff, these are thumbnails , click for enlargement. gasket face when lifted, you can see the source of the wee oil leak at the inner front DS bolt hole to drain, similar discolouration just in front of centre bolt hole.
[Linked Image]

[Linked Image]

Head face, no clean up yet.

[Linked Image]

Timing side chamber and valves

[Linked Image]

Drive side chamber and valves



[Linked Image]

Made in Taiwan, A copy of an OKO copy of a PWK copy of a flat slide keihin,Imitation is the game in town. in bits, 32 mm flat slide with power jet, chromed brass slide, Oring for float bowl and drain plug, no swarf, rubber manifold connector , spare fets ( unmarked no numbers)


[Linked Image]





[Linked Image]

Chrome slide and drain plug.
[Linked Image]

Bought on a whim, its an OKO rip off, checked further online, a genuine OKO has a Taiwanese flag on the box, this doesnt, unnumbered jets are another clue, the same seller has numbered jets so all is not lost yet, caveat emptor, it looks like it should work, time will tell.

Spent an hour cleaning up the head face, not done yet, going to waist the head bolts to thread minimum diameter and leave a bit of major OD top and bottom, this should let the whole bolt stretch when the head heats up, in theory, also going to get a flycut across the head face to clean it up , had this done 30 years ago, the coarse finish helped sealing, that copper coat residue is not easy to get off, cleaning up the barrels is not fun, gingerly scraping with a flat scraper at a shallow angle bathed in acetone fumes, inspirational! and nerve wracking.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725508
02/14/18 12:06 am
02/14/18 12:06 am
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Looking a little blacker than i would have expected Gavin but then if it had idled for a while before the strip down that would
account for it.
Those carbs are remarkable for the money eh? they are the type JRC sells so that would give you some pointers as to jetting.
I think they sell 30mm for 650cc kits but it gives you a starting point. (JRC's are Keihin) The fact they are flat slides may help
tuning if they are a bit big, it helps to obviate the 'gasp' effect and gives fast response.
Doing the outer bolt areas on the head is difficult, my brother made up a cutter that fitted on to a 3/8 shaft which screwed on
so you put the shaft through the head screwed the cutter on then levelled it up and gripped it in the mill chuck. I think he used
a left hand thread on it, all very neat. The joys of having a first class toolmaker around are many! My bungling would have taken hours.

Last edited by NickL; 02/14/18 12:12 am.


Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725530
02/14/18 2:47 am
02/14/18 2:47 am
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The last 5 minutes running would have been low throttle opening , dawdling through the village after a slow run on wet roads coming back from oban 12 miles away, I wonder if the vanishing epoxy also had some effect, seen it worse though, given the lean ish carb settings compared to before I was glad to see it wasnt fried inside,, the thickest carbon is at the corners of the valve pockets, rest of the crown is thin to bare in places., When the valves are out for refilling the port I will bonny up the Combustion chambers, the pistons will get a clean up in situ with some plasticene round the edges to keep the bores clean.
Last time the head was skimmed it only took a light cut to clean up, maybe 3 thou, Big Jock MacCallum set it up on the mill at work, parallel blocks under the rocker gasket face made it level, used a large fly cutter that had enough sweep to span the width of the face, used a pretty coarse feed so that it looked like a vinyl record, this worked well, all the machine marks vanished after SRM cleaned the head. Before I do this I will try Marks plan and check it with blue , at the last assembly I checked it right round with a 2 thou feeler but that doesnt get to the centre section. I have in the past lapped a head down figure of eight style with the old iron barrels ( not on this one though), thats a bit tricky with the pistons still in, cant risk grit contamination.

This motor has never seen 8,000 rpms in my hands, 7K absolute tops and thats maybe once a year, you are right about the 30 mm optimum, sweet spot for vibes is 4 -5 K, its plenty quick changing up at 5.5 especially with the well matched ratios in the 5 speed box.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725635
02/14/18 11:24 pm
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NickL Online content
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NickL  Online Content
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As for the head, skimming i thought you meant the areas above the head bolts that get mis-shaped and ragged.

My be worth looking at some valve stem oil seals, i used some toyota ones on the racer they were cheap and worked/lasted well.
Didn't have to machine the guides as i did with previous types, just stuck them on with loctite 638 i think.
I was never a believer in mirror finish head gasket surfaces on these things either, ok on a water cooled engine but to much movement
on iron/alley air cooled stuff.

Put that thin head gasket on this time and see how it performs, you'll notice the difference.



Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725641
02/15/18 12:01 am
02/15/18 12:01 am
Joined: Aug 2001
Posts: 3,641
argyll. scotland, uk
gavin eisler Online content OP
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gavin eisler  Online Content OP
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Posts: 3,641
argyll. scotland, uk
I wondered what you meant, penny dropped now, have used chunky head washers since day one so not too bad for distortion there, although now you mention it the bad bolt washer seat is a little concave, hmm, will get this seen to ASAP..
The last skim by Jock was maybe 30 years ago, Jocks dead now, , there' takin them out of oor pen noo, rock on wherever you are now Calzie.

got to pass on my favourite Big Jock story, When he was foreman at the station, he had his own office /howf down the hole , the fitters blued up the bog seat in Jock's office chanty, it also had a mirror , and after Jock waved off a mariner he spotted his blued arse cheeks, in a fury he jumped in the tunnel transport , drove out to the managers office where he proceeded to bare his arse to the boss , "Look what the bastirds have done!" . They dont make them like that anymore.

Finished cleaning the joint faces today, what a chore, blued the head and got the print on the barrels, good contact round the pushrod tunnels but only small witness marks at the front, the troubled DS front bolt had swollen top threads, its sister was similar but not so pronounced. I reckon that this being the hottest part of the head the threads on these bolts put more of a strain on the threads, definitely going to do the waisted bolt thing ., after a few iterations with a large radius scraper , just midges wings worth was enough to get a huge improvement in blue contact. I have good contact round the outer flange but little in the middle in front of the centre bolt., once the head is skimmed that should fix it, that centre bolt always took a touch more to re torque even before the alloy barrels went on , so i think the head face is a little concave at this point .The blue marks on initial rub pretty much mirrored the gasket discoloration at the front where the oil had weeped out.

Toyota valve seals, sounds like a plan.
I was thinking the same way about the thinner head gasket, couldnt fit one before because of the inlet rockers, pad grinding/ push rod thing, but with the old style rockers that isnt a sticking point any more, got to really in the interests of science and all that. If Mark Ps bike can manage on 12:1 i think a step up from 9 ish would be in order.
Any particular toyota valve seals?

Last edited by gavin eisler; 02/15/18 12:23 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725647
02/15/18 1:24 am
02/15/18 1:24 am
Joined: Jan 2014
Posts: 3,515
Aus
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NickL Online content
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NickL  Online Content
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Joined: Jan 2014
Posts: 3,515
Aus
Love the big jock story, bloody triffick. clap
My father in law was a Scot, it was years before i could understand what he was saying to me,
then i realised it was 'No, you can't marry my daughter!' Too late again..............
A Springside miner before he came south to Peterborough in about 1951 as all the pitts shut.

I just foraged on eBay for those seals, most corrolla's etc use 7/16 or 8mm valves just bought a few different ones and tried them.
They were so cheap it allowed experimentation.
You only want them on the inlets.
The vauxhall cavalier type i used before worked ok but the guides needed turning and a groove cut.
https://www.eBay.com.au/itm/Nitrile-Rubber-High-Performance-Valve-Stem-Seal-Oil-Seal-90913-02067-9091302067/332511234128?hash=item4d6b36c850:g:mR4AAOSw3q5aUCUP
https://www.eBay.com.au/itm/Valve-Stem-Seal-Oil-Seal-12210-PZ1-003-12211-PZ1-004-for-Honda-Civic-Acura/232621296589?hash=item36294f4bcd:g:XjoAAOSw3sRaUDF7
https://www.eBay.com.au/itm/Rubber-Valve-Stem-Seal-Oil-Seal-9091302053-90913-02053-Car-Accessory-for-Toyota/332511238195?hash=item4d6b36d833:g:aCsAAOSwoBlaUCa4



Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725674
02/15/18 9:24 am
02/15/18 9:24 am
Joined: Aug 2001
Posts: 3,641
argyll. scotland, uk
gavin eisler Online content OP
BritBike Forum member
gavin eisler  Online Content OP
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Joined: Aug 2001
Posts: 3,641
argyll. scotland, uk
Cheers for the links, V handy, they are cheap, wow, whats not to like.
The head is getting done Friday , blod in Benderloch has the kit and skills for this, Toluene came yesterday , no sign of the epoxy yet.

Side chat on oiling mod, Nigel Astbury- Rollason commented on a dual scavenge set up to reduce oil drag on the crank, like Nick's oil by pass to the head, the PRV disch to the pump got diverted to the tank via a 2nd oil return line. Thinking about both mods and chatting with John , both mods make total sense, with the PRV open and diverting oil to the return side of the pump, this effectively compromises the scavenge system and may increase sump oil level, causing drag and probably help spit more out the breather. NAR reckoned the reduction in oil drag gave another 5 HP on the dyno.

The Inside Story, Umberslade hall, jumped straight to the chapter on twins, not a lot of useful motor info, more about the chassis than anything else, one useful gem though, 71 on A65 heads had slightly more splayed exhaust ports, this is possibly why pattern pipes balance pipe stubs are missaligned, if they use the same jig for early and late pipes the stubs come out cock eyed when fitted to the 71 on heads.

Last edited by gavin eisler; 02/17/18 4:14 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725702
02/15/18 3:24 pm
02/15/18 3:24 pm
Joined: Aug 2016
Posts: 58
UK - Bucks
Steve Wilson Online content

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Steve Wilson  Online Content

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Joined: Aug 2016
Posts: 58
UK - Bucks
Hi. Hope you don't mind me jumping in :-)
Working on RF amplifiers (Big plated CNC aluminium blocks) the lids were screwed down tight with loads of screws Even the tiniest gap caused problems. One thing they did routinely was to counterbore all the tapped holes so when the thread stretched it didn't raise above the sealing face. Joint faces were small so a countersink would have opened it up too much. They only went down about a mm or so.
Steve


SJW
Re: alloy barrels + 5 speeds A65 750 OIF 1971 [Re: gavin eisler] #725714
02/15/18 5:50 pm
02/15/18 5:50 pm
Joined: Aug 2001
Posts: 3,641
argyll. scotland, uk
gavin eisler Online content OP
BritBike Forum member
gavin eisler  Online Content OP
BritBike Forum member
Joined: Aug 2001
Posts: 3,641
argyll. scotland, uk
Hi Steve, dont mind at all , open to all sorts. Thought about countersinking, there is very little real estate between the tapped hole and the edge of the bore, 1 mm counterbore might be possible, , I am making this out to be a big deal, it isnt really, if i wasnt putting epoxy back in the ports , I would have been happy with a re torque and calling it good, its snowing and grim here at the mo so i dont mind spending a few days weeks on getting more better. blue shows up very fine detail , it would probably stil havel passed a 2 thou feeler test, not many all9oy heads are dead flat, think a 3 thou tolerance is OK here. Saw a pic of your bike and got brake envy, whats that off?


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
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