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Piston ring end gap
Posted: Wed Oct 28, 2020 5:24 am
by Frunobulax
Hi all,
Regarding the piston ring end gap, the manual tells 0.15/0.30 mm for the top one.
What's your experience with those, do you think it's ok or too little?
Mine shows 0.15 mm.
Thanks
Re: Piston ring end gap
Posted: Thu Nov 12, 2020 11:25 am
by James P
This could be one of those topics of endless debate, a bit like fuel:oil ratios...
For many years I have used the '0.5% of bore size' (rounded up to the nearest 0.05mm) guideline for minimum ring end gap on all two-stroke engines with wire rings. In this case, it would be 0.30mm. I can say that I've never had any trouble with that gap being too small, BUT I can't say how much smaller it could be before trouble occurs.
It may be useful to hear from someone who has successfully and consistently used smaller gaps.
Sorry I can't offer any particularly useful insight!
Regards,
James
Re: Piston ring end gap
Posted: Thu Nov 12, 2020 2:27 pm
by Frunobulax
Many thanks for your reply James. The top ring is a Keystone type one, dunno if it make sence that the gap has to be such small then. Anyway it seems I will be the guy who will experience this first. I plan to do not cross the 6000 rpms for the first 1000 kms and then progressively open throttle for the 500 subsequent kms. I'll let you know if, unfortunately, the ring escapes straight into the exhaust...
