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Cam Bearing caps

1K views 4 replies 4 participants last post by  voxmagna 
#1 ·
Had a leak on the cam chain cover so a good strip down to sort this out. Decided to check the valve clearance at the same time. Now its been a while since i have worked on a motor of any description so imagine my horror when the valve clearance was way small on most of the inlet. and yes thought i got it wrong so i checked them 3 times ....even with different feelers. this is what i got ...1a=.006 1b=.004 2a=.001 2b=.004 3a=.001 3b=.003 4a=.001 4b=.001. now with working on the bike its notited that you can tell someone has worked on it in the past. Anyway just took the cams out and the buckets ( most are 2.85 and 2 @ 2.8) but i have also noticed that the plonker who worked on it in the past has put the bearing caps on in the wrong order.....the inlet was put on the outlet and outlet put on the inlet. Thinking back now i remember when i took the cover off the first thing i noticed was the grounding spring was on the outlet bearing cap rather than the inlet!. Anyway back to my question. Is it possible that by putting the bearing caps on the wrong cam would this have any effect on the valve clearence???. if so would it would be wise for me to put everything back AS IT SHOULD BE and check the valve clearences again......non technical answers would be hugely welcome.lol
 
#3 ·
The US and England - two countries separated by a common language. :teeth

Probably the best bet here is to post a picture of a bearing cap in place. At which point, one or two people will say, "oh that!".
 
#5 ·
A camshaft bearing shell would be considered worn if it had a thou of wear. That's a very small percentage of any valve clearance you are measuring. BUT it is very bad practice to mix up the caps because the caps are usually assembled before the final machining of their bores which ensures the camshaft will align perfectly on all bearings. You don't get such an alignment issue with just one bearing at each end, but when you have a center bearing, alignment is critical.

I think your observation of misplaced caps just shows what a poor job was probably done on the bike and you shouldn't be surprised if the clearances are wrong. Perhaps the same person got the valve buckets all mixed up too?

You should put the camshaft back with the caps in the correct position and repeat the valve clearance checks. You say you checked 3 times, but you should be rotating the crank each time. You already have one set of measurements and if you re-measure and the figures are very different, something is sad with your camshaft. Let's assume they stay about the same. Now calculate what buckets you need or if it is possible to swap any over. Normally I would say you can often swap a couple of buckets and get away with buying one new. But in your case, if a plonker has mis calculated and fitted the wrong size buckets you may not be so lucky at re-using some in different places. When the valve clearances on these bikes is correctly set up, despite what the manual says, you can go 100 K miles and not find them too far out. Certainly nothing like the 1 thou clearances you are getting.



 
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