Max piston size ?

[ISITME_LAPSED]

I've got the head and barrel off my 57 18S ( piston slap ) and can see the piston is already +40 with the ring gap 24 thou. Can I take it out any further and will there be a piston available to accommodate that ? I was thinking the company I get to rebore it would be able to supply a suitable piston but would it have to be a specific type of piston ?
Any advice and experience would be appreciated.

M

[dave16mct]

The club sells +60 500cc pistons.
Dave

[Greybeard]

Get the barrel measured up before buying any pistons. They'll tell you whether a +60 will take up the wear/rebore. They may also be able to advise whether a set of new rings would keep the engine going for a few thousand more miles. These old engines will keep going long after you think theyre 'worn out'
No reputable company will undertake the job without having the new piston to hand and unless its a place that routinely works on old stuff, the chances are you'll have to source your own piston.
If you can, try to locate a genuine Hepolite piston - Steve Surbey at AMC Classic Spares wont sell the currently available new replacements, though in the end it may be all you can get.

Steve

[Rob Harknett]

I agree with Steve, both rings and bores wear. No one ever seems to measure rings for wear. New rings may be all that is needed for 1,000 's of more miles.
P.S. When you submit a posting, give it time to upload. You made 3 postings.

[ISITME_LAPSED]

Thanks gentlemen, Paul at South Cerney Eng near me advised exactly that; get the barrel to us before you purchase a piston then they'll be able to tell me if the +60 will suffice. Every day's a school day !! Having seen the prices of pistons et al and not actually loosing / burning oil or having any sort of lip at the top of the bore, I think a new set of rings will be the answer.
It takes a while for a lifetime of jap bike mentality to understand the more laisses faire approach of these machines.
M
Oh, and to take your time when clicking a mouse. "Take a chill pill".

[Rob Harknett]

Thanks gentlemen, Paul at South Cerney Eng near me advised exactly that; get the barrel to us before you purchase a piston then they'll be able to tell me if the +60 will suffice. Every day's a school day !! Having seen the prices of pistons et al and not actually loosing / burning oil or having any sort of lip at the top of the bore, I think a new set of rings will be the answer.
It takes a while for a lifetime of jap bike mentality to understand the more laisses faire approach of these machines.
M
Oh, and to take your time when clicking a mouse. "Take a chill pill".

If you do have a small lip and only fit new rings remove the lip. I usualy DIY it using a scraper.