Scooterotica

Lads i will be fitting a honda 205 kit later and (dont laugh)cant figure out which way the piston goes the only marking on the piston are a faint 1M OR 1N ... now i guessed that it fits with the ring stops basically towards the exhaust port just want confirmation on this ... also gaskets i am assuming a base gasket for starters and do i fit a head gasket or a smear of gasket sealer ....Cheers Bill

Mine runs with the 'IN' towards the inlet (funnily enough ) ,a base gasket ,but no head gasket . I use red gasket (high temp) sealer or wellseal.

Cheers bud appreciate that never thought of it sayin "IN" lol ....still looks like 1N

If you mark the position of the ring pegs on the crown you should be able to tell easy enough if the ends run in the ports at all. You don't want that to happen.

I'd say you wont know if you need head or base gaskets till you dry fit and take some measurements. The main issue with giving straight answers is that machining of the gasket face height across 60 years of production is variable and what's right on one motor may not be right on yours.

Fit with no base gasket and see is the piston is out the top of the bore, if it is then you can use that as a guide to your base gasket / packer. If not out the top or level, then nip down the head and measure your squish. If squish measurement less the distance from the top of the cylinder to the piston <= 1.5 mm but > 1.0mm then you're probably OK with no head gasket if > 1.5mm then you'll need to use a thinner base gasket to drop the cylinder or have the head skimmed. If the squish is < 1.0mm then you need either to pack the cylinder up a little or use a head gasket to get the squish right.

Should be a matter of simple arithmetic.

You are 100% regarding the gasket face i have two casing with a difference of 1.5mm from the back of the crank to the gasket face the casing i am using is spot on and was measured against an innocenti SX200 casing also the kit was done apparently on a jig using innocenti measurements so hopefully shouldnt have to much mucking around to do but yes i will be measuring the squish as a matter of precaution ....Thanks for the input

yes ,deck heights on different cases need to be taken into account