The New And Improved Unofficial R65 Forum V2
Technical Discussion => Discussion about "Lesser" makes, er, Non-BMW ;-) => Topic started by: Semper Gumby on November 18, 2008, 08:03:57 AM
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I realize that somewheres below the dreaded Oil Thread (ADOT) well below most political threads lies the Engine Break in Thread!!!!!
BUT I am just about finished with installing the A65 motor in the BSA Thunderbolt and am about to crank it up for the first time. I have been pointed to this persons website. What he says makes sense to me but I am thinking about what you guys/gals might say about this subject. Thanks in advance for your thoughts.
http://www.mototuneusa.com/break_in_secrets.htm
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I remember stumbling across this site several years ago and it is very similar to what was recommended to me a number of years back, "Break it in the way you are going to run it!". I think the most important things during breaking are to vary RPMs and don't "lug" the engine...
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Hmm, a restriced pornographic page? These net nannies are retarded.
Bill, what material of rings did you use and what grit was the final honing?
www.britbike.com is a good web site for British stuff. Of course, I never peruse the BSA section. ;D
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I agree withe the guys above, though I don't have huge experience in engine rebuilding. I wouldn't run it to redline at all the first 1000 miles, but you really don't want it "lugging" either, and do vary the speed/RPM frequently. Use the engine's compression while braking/slowing, too. I'd say, "don't use synthetic oil" for the first 2000 miles, but this is old british iron, after all - so you are most likely using pure dinosaurs in it. I would change the oil after the first couple hundred miles to look for metal bits, and hope that I didn't find much of anything.
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Copy that. Thanks all!
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200 miles and no breaking. I have switched to Voldemart 20W50 at 40 miles but still no joy. The bike doesn't smoke at speed but when it idles it smokes. Arrrgh. Burning a lot of oil!
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What did you lube the pistons/cylinder walls with upon assembly? I used to use oil but a wrench turned me on to using ATF for a quick ring-seat and it's worked pretty good on the past couple engines. If what you lubed them with was a bit too slippery maybe it's causing you problems.
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Perhaps a silly question, but you did check/set the ring gaps after installing the new rings ? What brand of rings/pistons are you using ?
Is this the first oversize set for the engine, or ?
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What did you lube the pistons/cylinder walls with upon assembly? I used to use oil but a wrench turned me on to using ATF for a quick ring-seat and it's worked pretty good on the past couple engines. If what you lubed them with was a bit too slippery maybe it's causing you problems.
The guy who did my R65 heads told me to use darn near nothing (two drops of oil on each piston/bore), but old Britbikes have different material pistons, bores, and probably rings. Come to think of it though, I think my Triumph was pretty dry inside the bores when I assembled it. I was more concerned with using assembly lube on the big and little ends and the main bearings.
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The motor was built by a local BSA guru using new pistons and rings. He wants me to try something before bringing it back. Which I will do after the new battery gets here. My SLA battery died while the motor was being rebuilt (even though it was on a trickle charger). One year and seven months. (sigh)
TTFN,
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The end of the story is end gap on the new rings was too large (Hepolite rings fixed that) and there was too much wear in the vlave guides.
All fixed. Oil runs clean and not burning a drop (leaking in various places but not burning). ;D
Joy.
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Woohoo !
It's time for a cold one, I think !
[smiley=beerchug.gif]
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Many beers consumed in Hiawassee GA at the Georgia Mountain Rally this last weekend. Rode the T-bolt to and From the GMR on Thursday.
Oil is running clean and is not going away!!! :)
Now about those leaks....
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"The motor was built by a local BSA guru using new pistons and rings."
"The end of the story is end gap on the new rings was too large "
is he still a guru?
seriously, what sort of "guru" (other than the local pub hero) would not check ring gap by installing into the piston top before installing into the piston.......basic, basic, basic, something like common sence that is being lost today.
It worries me......
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in a past life......
years ago I ran a motorcycle shop in Adelaide, Southern Honda, on main South Raod Morphettvale.
we all played boy racers then, and the fastest fella on the track was aguy named Grag Pretty. (I was Honda, he was Kawasaki, so he had 900, we had 750). Greg was always the fastest bike, but he would also talk to us all. On the straight, his Kwaka 9 would shoot past all the other Kwakas, no problems. He told me he takes a new bike from the crate to the track, no mucking about with it, runs two or three laps to warm it up, then redlines it every gear for the rest of the day....that was his secret, and he swears he never did any illegal inside work (we were proddy bike then)...there is NO DOUBT the difference was radical.
Did I ever do that....no.......did I ever win a race.....no.
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Last month I rebuilt my engine. Exhaust valve broke piston.
It was my first work and actually the engine run well, it has 600km. I think now I have finished break-in. I only had a trouble. Old pistons had 82mm of bore. Now new pistons had 82.5mm. I don't balance the weight. New and old pistons had same weight? How much is weight tolerance between that components? +-3grams? I have not good vibration at 2500 and 5000rpm... it's normal? is only after I did that work...
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Depending on brand/mfg of the piston, some of them are quite close out of the box, though they should be checked and "shaved" if out of tolerance - I don't have the factory tolerance for piston mass handy, but I'd be surprised if they were BMW pistons if they'd be more than a gram or two different, but I haven't actually rebored a BMW (all my experience is with Japanese bikes in this regard) Are you using the same connecting rods as before? Did you check the crank journals and bearings for play before installing new pistons?
Someone with more airhead re-bore experience than I will chime in soon..
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If your new pistons are .5 mm larger diameter, you have the second oversize pistons, did you get the correct piston rings ?
I just saw something in the BMW shop manual, that I didn't know before, but apparently there is a correct and an incorrect way to install the pistons.
There is a caution in the manual that states that : 'the installed direction of the piston, has the arrow and word 'vorn' face forward'.
Anybody have a piston out of their bike, to confirm this ?
It looks like the piston pin is offset from the center of the piston by 1.5 mm (.060 in.) .
I don't know if this will help or not, or just cause more confusion .
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Thank you! Yes that's second oversize pistons. Who gave me pistons gave correct rings and pin too. I think only different weight between old piston and new +0.5mm + 5-6grams. It's possible? I think to reopen engine and cut a little portion of new piston...
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There's no dealer who had a pair of pistons and measure difference between that?