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Hi Steve, The cylinder paint looks really nice. What paint did you use?
Don


1973 Tiger 750
Triumphs on eBay
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Steve - Love the subtle "jigsaw puzzle" reference..........


1978 T140E
1979 TR7V
1960 Royal Enfield Bullet 350
1973-81 (6x) Bultacos
Waste not, want not.........Thrift is a virtue.
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That's a thousand piece jigsaw puzzle, more challenging than the Triumph!

Don -

Rust-Oleum Engine Enamel (High Heat 500F)

As for the head, I've got a semi-gloss paint for BBQ grills that I'm going to try and use on the head. The Royal is basically a 4-valve TSS. The engine cases, head, rocker boxes and inspection covers were painted black. Not sure if it was a straight spray-on paint or powder coat. When I took the engine apart, lots of overspray inside the cases and inside the rocker boxes. Looks like they were painted before they were fully machined.

I opted to not repaint the engine. They're only original once and the paint is still in pretty good shape. The head, however, is all bare aluminum, which means either the head was replaced at some point (doubtful, but I could check with a call to the PO) or the head was vapor blasted when guides and valves were replaced (in 2001).

The edges of the fins on the head, rockerboxes and inspection covers were sanded back to bare aluminum.

This link shows some of the engine detail when pics are enlarged: http://yampyweb.com/royal/owners/frankfl/pix/index.html

I hope the BBQ paint for the head is close. It doesn't have to be an exact match as most of the head is hidden once the bike is fully assembled.

Steve

IMG_3368.jpeg
Cylinder Paint

IMG_3356.jpeg
Machined Rockerbox

IMG_3357.jpeg
Underside of rocker box fin - rough casting!

IMG_3355.jpeg
Aluminum paint finish


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Cylinders are honed but there are still vertical scores visible. Bores now measure 3.0121” on the drive side and 3.0123” on the timing side.

Pistons measure 3.0060” and 3.0058”, so looks like I’m going to rebore to .040” over unless someone has a better idea.


Any suggestions to where to send the barrel and pistons for a rebore? I’m on the east coast (MD)

It was worth a try!

Cheers,

Steve

D0B5297C-73CD-4460-BFE1-8CDC0BBE99AE.jpeg 2F406590-FFD3-467F-9B87-E869A6EA954D.jpeg

'77 T140J Silver Jubilee
'82 T140LE TMA Royal
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Hi Steve, Better idea is buy new modern Bonnie! I think about that often!

Other than that…. .040 over is a good plan. I have no idea who is good in eastern USA. Pretty much .006” clearance is just too loose. Will rings seat. Probably. But I’d expect pistons will rattle sooner than later.

After bore & hone my clearance was .0037”. 220 finish hone. Sometimes I wonder if 180 hone is better?
That is the close clearance of factory spec. Using Harris 7.4 pistons. Thing is with honing how much pressure the hone is set at can effect roughness as well as grit. Factory recommend 150, but that was with genuine rings.

I have no true, idea what rings are best, based on long term use.

At the car dealership a few of us techs thought about these things & durability. Always looking for better. Most did the job & shipped it. I suppose most the old Triumuph dealer techs are gone now. Plus ring materials & technology changes. So what worked good 30 years ago may not today.

My original from new Triumuph Hepolite rings proved very durable.
Don


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Steve, That’s a very nice hone patted.
What did you use? What grit did you use?

By the way I used same cylinder paint.
Don


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Thanks Don -

I have a 2018 1200 Tiger xRT, so that's my modern ride. I take that one when I want to ride two up, or I need to carry something or the weather looks a bit suspect or....it's nice too have freedom of choice!

I used a ball hone, 3 1/8" Dia, 180 grit with WD40 for cutting. I figured I'd be close to out of clearance specs trying to get rid of the vertical scoring, but .0060"+ is way more than I'm comfortable with. Really don't want to listen to the sound of a teaspoon rattling around inside a coffee mug every time I go to start it.

I ordered a set of + .040" LF Harris pistons (7.4:1). The oil control ring on the Harris pistons is three piece. The rings I have ( Hastings, which I will sell on to someone else b/c they're .020" over) are one-piece oil control.

Any pointers on how you file the three piece ring for fit without damaging the wire and spring? They are delicate to be sure.

I searched the archives here for machine shops and some of the guys mentioned a shop about 30 mins from me: Coleman Machine Shop in Linthicum, MD.

Bob Coleman has been operating the place for almost 60 years. That was in 2008, I'm going to call today. Hopefully, he's still around.

Cheers,

Steve


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What does Triumph say about when it is time to overbore? I recognize that .006" is more than you would want for a new piston and cylinder, but it doesn't sound worn out to me. I recently redid the top end on my Velo. The spec calls for .004" clearance on a new piston cylinder install. But Velo says you don't need to overbore until you have an additional .008" on top of that (a total of .012"!!). My cylinder was out of round by .0015" as a result of previously being bored at an angle (not that uncommon) plus there was wear. Randy Long in Chester, PA (one of the best motorcycle machinists around and very reasonable prices. Old school though, no internet and no credit cards) fixed it up for me with a rigid hone. I ended up with .0075" clearance using my existing piston, which was well within Velo's specifications, and didn't have to buy a new piston. If it was my bike, I would package up the cylinder and pistons and send them to Randy and ask for his opinion.

Ed from NJ

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Originally Posted by edunham
What does Triumph say about when it is time to overbore?

Hi Ed -

Factory manual calls for .0036" - .0042" clearance. I could probably get away with ~.0060" clearance (could adjust ring gap to help make up difference too). If I didn't have those vertical scores in the bore, I'd be inclined to try it, but at this point, between the condition of the bores and the excessive piston/bore clearance, I think a re-bore is prudent. I'm open to ideas. Just looking to make the machine mechanically sound so I can ride it!

Cheers,

Steve

IMG_3388.jpeg
Piston/Bore Tables

Last edited by JubeePrince; 02/01/22 7:40 pm.

'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

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And after reading this thread:

https://www.britbike.com/forums/ubb...true/piston-ring-gap-standard#Post532362

I'm once again paralyzed by the choices....maybe ~.060" piston to bore clearance is OK with a revision to the ring gap? Will the rings still seat with those vertical scores?

And.....discuss!

Cheers,

Steve


'77 T140J Silver Jubilee
'82 T140LE TMA Royal
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Hi Steve, There is more to it than clearance. What is out of round & taper.

The rule of thumb we used for scratches is, if you can catch a finger nail in it. Rebore. If not use it.

Obviously a rebore is the sure bet. You have so much $$ in this so far what’s another $400? Right?

So really it depends on what you want. Should it fail to break in, Or uses too much oil, you’re only out the gaskets.


If you don’t mind another tear down should it fail, give it a try.

I find taking top end off is very easy. My bike has push in pipes that are very hard to remove & install. Nothing wants to line up!!
Push over pipes are pretty easy. Problem is, once push in starts getting snug in head hard to rotate them. Kicker wants to hit muffler. Front pipe wants to contact oil pressure switch boot.

Personally if you are willing to put up with some piston rattle cold, I think it would work.

750 pistons are a fair amount shorter than 650 pistons so less forgiving of clearance & noise. T140 are so noisy anyway you may not notice it.

End of day do want safe bet, or willing to rebore later.

With the sublet labor for bore & C630 guide install my overhaul bill was $4500. That includes new lay shaft & some gears. All new bearings etc. Also includes the $100 I spent on CN bearing I couldn’t use. What’s wrong with power plant determines parts bill.
Don


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I agree with Don.
Does your thumbnail "catch" in the scratches?
If so then rebore.
But if not then you do not need top rebore.
Sometimes what look like scratches are stains.
Just my two cents worth of course.

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I've mentioned it before- Line to Line coatings will coat your existing pistons .020" or whatever you specify to get them back into spec.
If you're going to put off a rebore, this may buy a little (or a lot) of time on your existing parts.
As Don said, nothing but a rebore will fix out of round or tapered cylinders. But if the bike was running before, chances are good that it will run no worse than it did.

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Originally Posted by Tridentman
I agree with Don.
Does your thumbnail "catch" in the scratches?
If so then rebore.
But if not then you do not need top rebore.
Sometimes what look like scratches are stains.
Just my two cents worth of course.

Thanks Richard -

Can’t hook my nail on them, so they are either *very* shallow or stains as you said.

Steve


'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
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Originally Posted by Mike Baker
I've mentioned it before- Line to Line coatings will coat your existing pistons .020" or whatever you specify to get them back into spec.
If you're going to put off a rebore, this may buy a little (or a lot) of time on your existing parts.
As Don said, nothing but a rebore will fix out of round or tapered cylinders. But if the bike was running before, chances are good that it will run no worse than it did.

Thanks Mike. Might be worth looking into. I haven’t measured the bores 90 degrees out since the hone, but worth checking. If it’s not too bad, maybe a piston coating might be the fix.

Cheers,

Steve


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Looking at your photos, those vertical scratches don't look like much to me. I think they would have about as much effect as a slightly large ring gap. I would call Randy Long. 610-286-5870 74 Risbon Rd., Honey Brook, Pa 19344. He is not all that far from you. Those clearances you have cited from the manual are for new installations. They do not tell you when the cylinder has worn to the point that a re-bore is in order. I know that friends of mine back in the day would set Triumph 500s up with .005" clearance on fresh top ends to avoid seizures.

Ed from NJ

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I do not see any problem regarding oil and that vertical scratch however; may be the clearance is too much but what will be the use anyway?
That is the important factor.
I do not see many using these motorcycles as daily riders or being hard on the engines so what could be the problem? To use the bike at slow speeds and couple of days per month; you would not have any problem.
I have been using these old machines, many from the late 40s to take the road and the engines did the job always. The problems were for negligence of previous owners not due to a clearance of thousands...
By the way; I am not in the cheap side.

Last edited by reverb; 02/03/22 6:42 pm.
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Thanks for the feedback thus far.


I've been making progress, but life gets in the way too. Marzocchi Shocks are rebuild and installed.

As the bike was running before teardown, I'm going to try and break it in with the hone I gave the cylinders and new rings with existing pistons. Worst case scenario: the rings don't seat or it burns oil, then I take it back down and do the rebore then. Ring gap is checked and rings installed. Going to install pistons and cylinders in the next few days.

Rear brake is done, still need to get some parts for breather assembly, rebuild the MKII carbs (with UK jetting specs), get a stock exhaust system (I'll be putting the existing one up for sale in the garage sale forum soon) tidy up the wiring and electrical connections and, and, and.....

Progress, not perfection!

Cheers,

Steve

IMG_3602.jpeg
Last edited by JubeePrince; 03/14/22 11:33 pm.

'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
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The head on this bike was stripped of paint by the PO because he was concerned about engine overheating. crazy I decided to just hit it with some alum. primer and engine paint after soda blasting, then polished/sanded paint off the fins to bring the engine back to its original paint scheme (rocker boxes and tappet inspection covers are same scheme).

I'm going to use the existing valve train to break in engine. I lapped the valves and did a leak test with good results. Had to redo the timing side as there was a small leak of gas from the combustion chamber, so all good now. I'll probably redo the valves guides this fall after engine/cylinders/rings are broken in. Couple of valve tips are a bit hammered, but serviceable.

The more I delve into this bike, the more I'm amazed these things still run after their treatment by PO's. This bike had black silicone/construction adhesive (PO was a carpenter) EVERYwhere. Gasket surfaces on the primary, timing chest, starter, gearbox cover, instrument binnacles, on top of gaiters installed on the Marzocchi Shocks. It was even used to secure some wiring instead of zip ties or the like.

Happy to have saved this one from an uncertain future. After doing some research from the papers/receipts/correspondence etc the PO gave me, it appears that according to the VIN number, this is the very last TMA Royal model to leave the Meriden line. Supposedly there were only 50 TMA models made/exported, so it does make it a bit of a rare bird.

Steve

IMG_3678.jpeg IMG_3687.jpeg IMG_3688.jpeg IMG_3691.jpeg

'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

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Steve, any chance this bike will make it to the three state? I'm anxious to see it.


Hugh: Proof the Dodo is not extinct
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I hope so Hugh! My goal is to fire it up by the end of the month....

Cheers,

Steve


'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
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The things you find on these bikes...

When I took the bike apart, there were no O-rings in the top of the PRT tubes/head. Bit of a head scratcher, but I thought "I'll examine it closer" when it goes back together....

Installed the pistons and cylinder(s) yesterday and decided to put the head on to check PRT crush. Was a whopping ~.106"(!) Checked and rechecked everything (made sure PRTs and tappet guide blocks were correct), then I examined the PRTs a bit closer. I cleaned the PRTs in parts washer but did not paint or restore them (they're painted black on the TMA Royal model).

The PRT's had a "thick" shoulder on the top end of them, but being the later model version, I assumed this was by design. Upon closer examination, each shoulder had a black, plastic "spacer" or distance piece glued to the shoulder. This was why I could find no O-ring on the top end of the PRT's at disassembly. I guess the PO created a "QD" version of head removal so there was no need for O-rings at the top end...

It must have worked, b/c when I checked the head for warping it was only out about .006" and there were no signs of oil leaks. I cured the head warp by bolting it to the cylinder(s) and baking it in a 280F oven for an hour.

After getting rid of the plastic, I found the crush measured to ~.030". Progress, not perfection!

Cheers,

Steve

IMG_3698.jpeg
Head and barrel(s)

IMG_3697.jpeg
PRT


'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

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Fitting round pegs into square holes since 1961...
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...but 0.030 is excellent. Why you do not like that gap?
How did you checked the warp of the head?

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Fernando - just an expression or idiom. I’m very happy with .030”.

I checked the head with feeler gauges on a polished granite countertop. The gap was located inline with the PRTs and two 5/16” studs.

Steve


'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Joined: Nov 2005
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More progress…

9518AC91-0A42-41EB-9942-21C27F8E4140.jpeg

'77 T140J Silver Jubilee
'82 T140LE TMA Royal
‘69 BSA Rocket 3 (patiently awaiting it's turn)
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
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