Hi guys,

Can anyone help me with the standard piston bore size of the 240 (212cc) engine to the nearest mm. 

if anyone has a scrap piston available and has time I would also like to know the gudgeon pin diameter, crown height from pin center to piston crown

and the overall piston height. These can be just a ruler measurement. 

Thanks in advance,

Prelit

Edited January 3, 20206 yr by prelit

If it's Fantic 240 your after  69x56,5 mm

 

Edited January 3, 20206 yr by Bilko

Good source for info https://fantic240pro.pagesperso-orange.fr/ukindex.htm

Thanks for the info and link Bilko, much appreciated.

bore 69mm ,overall hieght 75mm, center pin to crown32mm, pin dia 18mm There is also letter stamped on crowm A to G

Thanks Midlife for taking the time to measure those dimensions for me.

I believe the the Fantic barrel was plated, has anyone got any experience with running the piston in a cast iron liner. I guess in theory the piston ring wouldn't be 100% compatible but 

can you get away with it?  I bit of premature wear doesn't bother me.

Cheers,

Prelit.

Why do you want to try a cast iron liner?is the cylinder deeply scored.Theres companies out there that can repair seriously damaged cylinders and replate them

Hi Huski,

I'm not wishing to run this piston in a Fantic barrel. I'm just after a 68mm to 70mm piston to run in an alloy barrel with a cast liner. 

Thanks,

Prelit.

I put 2 and 2 together and made 5.Cant see a problem with what you propose

Provided the piston rings are suitable. You can’t run chrome rings in a chrome bore, they’ll eat each other! You can run chrome rings in a cast iron bore. The top ring is usually chrome to deal with the high heat of combustion. 

Thanks for the prompt replies guys,

Does anyone know the material of the Fantic piston ring and if the barrel chrome, nikasil, plasma or something else?

Cheers,

Prelit.

Chrome rings will be shiny just like chrome. Plain rings will be greyish to polished grey where they rub against cylinder wall. Chrome bore will be easy to spot as it will be much shinier than cast iron bore. You will also see where the plating finishes on the bottom of the barrel/bore. Obviously chrome bores cannot be bored out, unlike a cast bore which can be oversized by reboring. Nikasil and other types of surface hardening processes are harder to define, try a Google search ?