Ring gap on a four-stroke?

[hmmmnz]

well i have a curious wee encounter
the bike is a xr 200/250 (200 frame, and soon to be 250 engine)
i bought the engine as "going but smokes"
so i have stripped the top end,
the piston measures 73.87mm across it, (standard piston)
but the barrel measures 74.55mm
with a ring gap of about 2-3mm

hmmm
lol, the bore doesnt seem scored and i doubt that it would wear half a mm,
but who in there right mind would go to the hassle of a rebore to half a mm over size and still use the original piston???

so what say you savages??
a royal fuck up, or something else

should i go for the next rebore 74.75 and new piston and rings
or keep the bore the same and get 74.5mm piston and rings

[F5 Dave]

Hahaha classic! Maybe they thought it would swell to fit?

I once bought a 2 stroke engine that had supposedly been "reconditioned by (well known) bike shop" I popped the top off to be sure & the piston had internal plier type circlips instead of wire ones. Hmm, no mechanic has done that. Maybe they meant they bought some parts there. So I kept looking & there were no bottom end seals, just the dust covers on the main bearings, which shouldn't have been there anyway & they weren't C3 bearings anyway. Bet they tried to start it like that & gave up so sold it on. Was cheap enough so no drama & went fine once bogus parts replaced.

[hmmmnz]

i bought a smokey, that had the top end done by a bike shop, and not long after it stopped running,
when i got it home it didnt even have the circlip in place and the pin had scored a huge gouge in the bore, so much so, the barrel wasnt redeemable of course i had to buy another 2 bikes to get a barrel that was in ok condition, the joys of rare 2 strokes on the plus side i now have loads of spares

[F5 Dave]

A mate bought a FT400 ('orrible 'onda attempt at a flat-tracker with a XR type engine detuned to useless) & he went touring down south (two up would you believe?). Became concerned when it was using more oil than gas. From factory one circlip. Doh!

[thepom]

stranger from another planet,welcome to our hole..just strap on a guitar and we can play some rock and roll....