piston clearance on a gs 160

[stevec]

What clearance should there be on a 58.2 mm GS 160 piston trying to reuse a nos vespa piston in an old 58.2 bore

Trying to avoid using a pattern piston.

Info is nowhere as easy to find as lambretta

I remember 4" thou for a lambretta,150cc can they run tighter being a less stressy engine

Does anyone have an NOS 58.2mm piston rings for sale

thanks


steve

[Smallframe]

Quote taken from international BBS scooterist forum . Hope it helps

This is a question for any GS160 owners out there....I still have the original small end bushing,and at certain RPM's have a small rattle from the top end.Top end is first oversize,and 2 thou. piston/wall clearance.
Tried 100 octane gas to see if it was a timing issue,and it is definitely not "pinging".Scoot runs great other than the "rattle" which I have ever eard on a Vespa engine before,so am thinking it is the top end bushing.It is more audible at mid-high rpm under load,and it is the original bush with 33k kilometers on it.
When rebuilding the top end,slid the piston pin in and the play did not seem excessive,and the rattle is still there just like it was before I rep