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Hi Tony
If it was broken on assembly would it not have been smoking earlier than at 100 miles ?

I'm not questioning your opinion, just curious and would like to know more behind your thinking on this ?

Thanks
Drew
ya, you're right. but we don't know if it smoked or how much it smoked on start-up.
We may never know how the ring got broken, it's not very improtant now, the guy want to ride so he needs another set of rings.
It is important not to do the same thing again.
 

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Discussion Starter · #22 · (Edited)
The very first start up it blew out a bit smoke, which I figured that was assembly lube and such. Had some carb issues so it was running rich. sorted that out. Timed it with the gun and set the valves. Ran strong, real strong. I put the kick stand on a block to keep the bike level. The times that I didn't it would puff a bit of smoke but would go away immediately. It could have started earlier but only noticed when I had it running in the garage and sun was shining in the back door highlighting the smoke. It really was not that much, well enough for to shut it down and investigate. I do need to say that this bike is a monster. Granted it has drag pipes but no shit you can feel the concrete in my garage vibrate when it fires up. And far as off the line, forget about it. I can't wait to get it on a track of any kind. The original owner said the bike was "special". Now I'm starting to see why.
 

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Thanks Guys
I really find this stuff interesting, there is lots of build info around, but not much in the way of diagnostics so I like to take note of this stuff. Not many guys left here in Oz still doing Brit Bikes, a lot of valuable experience and knowledge lost.
As Tony said, the important thing is to get it running again not spend hours investigating the failure.

You gotta video your desert ride and put it up here !
Cheers
 

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Double check the piston size to the bore size... You need .0045 clearance.. I have seen a bunch of cylinders bored incorrectly with .002 and its simply not enough clearance.... Also had a bunch of bad rings with too big a gap.. Make sure the bevel is on top of the compression rings when you install them... Looks like it got a little tight, so I would get the mic out and check, double and triple check, then have it corrected by a reputable machinist... BTW whats the piston look like??
 

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In all my motors I've lubed the cylinder walls, because they sit. However they are all car motors, I have never run into an issue seating my rings. I also have my own break in procedure of acceleration, downshifting, and multiple speeds for about 20 miles. Oil change, she's a runner... Good luck on the fix
 

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On a Triumph, it has to be assembled with the rings dry.. These are not car motors, they are air cooled high revving racing engines.. Tony and I discussed this and he was the one who informed me of the machinists boring the cylinders with the car measurement of .002... Its not enough for an air cooled engine.. Aluminum expands when it gets hot, and you might get 50-60 miles on the bike without a problem, but once you take it out, and get on it they seize up quicker than shit... Its like pulling teeth to get a machinist to bore .0045 clearance because they think its all sorts of wrong...
 

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On a Triumph, it has to be assembled with the rings dry.. These are not car motors, they are air cooled high revving racing engines.. Tony and I discussed this and he was the one who informed me of the machinists boring the cylinders with the car measurement of .002... Its not enough for an air cooled engine.. Aluminum expands when it gets hot, and you might get 50-60 miles on the bike without a problem, but once you take it out, and get on it they seize up quicker than shit... Its like pulling teeth to get a machinist to bore .0045 clearance because they think its all sorts of wrong...
Nice to know! What about ring gap? The motors I've put together are all turbo'd so depending on the bore size I'm usually between .024-.026. (first ring) .028-.030 (second ring) (4 inch bore). So on a triumph motor because of air cooling and heat is it recommended to gap the rings wider to reduce the chance of butting?

Thanks for the info I put together a BSA motor recent, and was't aware. I may have to re-open the top end and redo!
 

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General rule to follow is .004 for every inch of bore... Normally on a 650 I like them at .011-.012 but thats not always possible depending on the rings, size of piston, and size of bore.. Have to make due with what you got...
 

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Discussion Starter · #33 ·
Everything looks fine. The guy that did the machine work is highly reputable and is a performance motorcycle machinist and I think he used to work for Triumph. He had the pistons for measuring when he did the cylinders. As for the kickstand thing, As said previously I keep the stand on a block to prevent that. I'm not going to lie to you. When I felt that it was pretty much dialed in, I did not baby the bike and I'm not going to either. Maybe that was what cracked the ring, who knows. I'm a nut for getting the most out of something. Which is why "Can't leave well enough alone". Hopefully round 2 will have better results. OK so, no oil on the rings for install. Ring gap no more than .014 and no less than .012? No fancy pants oil. Carb is dialed in way better than when originally fired up so that should save some grief. I did the timing with a gun last week but will definitely double check. Reset the valves and off into the sunset. Thanks for all the input. This place is a plethora of info.
 

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Wow I've put together several motors with the rings oiled, and it worked out fine. I'll try doing this dry from now on but I figured the cylinder wall and rings need some oil for startup.
If oiled rings work for you, don't change your assembly technique. It's always worked for me too. There is no oil with a film strength adequate to resist the unit area pressure created by the peaks and valleys of freshly machined parts, so an oil film on start up is certainly not going to interfere with ring seating if everything else was done correctly. Besides, after a few seconds running the crank has slung oil on the cylinder walls anyway, even in a dry sump engine. If oil on the cylinder walls was a problem, no rings would ever seat.

Bob
 

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when it come to putting rings in a motor two things change from the 1960's, the rings and the oils.
as for me, what used to work back then doesn't work anymore.
there are certain oils and oil additives that have warnings about using them on new engines because the anti-friction additives will not let motors run in.
at my shop we do 3 or 4 motors or top end rebuilds every month,
about 4 years ago we were having issues with rings seating, and we found out other people were saying the same thing. the only cure was to put the rings in there dry with only a little oil on the piston skirt. A misfiring plug or a badly adjusted carb, and timing has a lot to do with how well the rings seat. The first 60 seconds of running is where most of the seating takes place and once that cylinder gets glazed the rings have a real hard time ever seating.
as for the piston to cylinder clearance we use .0045 other people set them up at .002, we found some engines set up that tight have seized pistons on a hot summer day.
all I can say is what works for us using todays rings and oils and the clearances we use.


another thing you should do is wash your cylinders in soap and water after they are bored or honed.
 

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Discussion Starter · #36 ·
Sorry if this oil line question is redundant. I'm having a hard time wrapping my head around the custom tank thing and yes this tank is plumbed on the inside for a Triumph. Can I run a line from the the crankcase breather to the breather tube (the middle one) and tap into the froth tower nub at the top of the tank and run a line to where ever from there? As it stands right now the "nub" has no opening and that middle tube is my vent to the atmosphere. Just asking.

 

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Discussion Starter · #37 · (Edited)
Got it all back together. New rings gapped at .012. Little booties for the intake valves. I had a gander at the Jet needle. rolled it on my 1/2"piece of glass. It was wonko. Got a new one. Static timed it as I have done in the past. In get a few pops like it wants to start but it just won't commit. At least I've got my cardio out of the way for the next six months. Help, I only have a few days left before the big move and desperately want to get this out in the desert.

By the way double checked timing, double checked for air leaks, annealed the head gasket, new rocker box gaskets new intake port gaskets. The valves are set to 6 on the exhaust and 4 on the intake as instructed for the first initial start....if I get it to start!
 

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Starting an engine with no oil on the rings is a bad idea. You want the rings to spin in the bore, and with no oil they can micro-weld and cause damage. No oil on the cylinder walls is fine, but you should have at least a light oil in the ring grooves so they will be able to rotate during break in. This is just my opinion, some guys throw bon ami into their carb to seat the rings. Whatever works for you, but it won't ever matter unless your cylinder is round and straight, and is finished properly.
 
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