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jawa-enfield wrote:
Mon Apr 04, 2022 11:14 am
Guys, the omgema accralite piston... 0,07 inch, about 0.10mm piston clearance, right??

There's 0.20mm play!!
did they make a mistake at the workshop?
Your figures don't stack up. If you mean 0.007" [which I would think is too much for piston to bore clearance], that would not equate to 0.10 mm, which is almost exactly 0.004". Your 0.2 mm play, is therefore in the region of 0.008". It might be best to stick with one unit of measurement or the other, or mistakes could be made.
12 months later and your no further forward.
You asked the same question back in April 2021.
4 or 5 thousands of an inch would be normal for a 500 barrel.
You say the Accralite requires a little more.
What clearance do you have with your barrel and piston?
Jawa-Enfield. Your piston-bore clearance is too great. My 535cc accralite instructions say 5.3-5.7 thou. NB: that is total clearance, NOT each side. Maybe you'll have to resleeve it - yes, it can be done with a 535cc barrel.
Check your ring-gap clearances – these should be as follows (also accralite instructions):
Top ring = 10-16thou, 2nd ring = 12-18thou and oil ring = 8-16thou, all located about midway down bore – use a piston to push the rings down AND keep them level.
Did you give the bore a proper plateau hone?
If your breather is not efficiently lowering crankcase pressure, your engine will piss oil out of every possible orifice – especially at high revs.
Good luck
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