Cylinder marking or piston marking?

[d2w]

Folk,

It's time (200hrs) to do a top-end job on my EC300, but I'm confused about which piston size to get.

The marking on the back of the cylinder is "A" while the marking on the OEM piston is "B" (22502-33).

I plan to buy a Wossner piston, but for which size?

I'm sorry (for me) but I don't have access to or own the preferred cylinder measuring tools. Consequently I have to make a "best guess" for the correct size.

Thanks for your advice.

Dale

 

[Zman]

Unless you want to guess, take it to a motorcycle shop or engine rebuild shop and have it measured. Can you feel any ridge at the top of they cylinder?

 

[n_green]

If the cylinder is stamped A and it is in good condition with lots of visible cross hatching and no detectable ridges or defects in the bore using your calibrated fingernail I'd say its pretty safe to order an A size piston

 

[Neil E.]

If it had a B piston in it from the factory it should be safe to put one in now. The actual difference is very small, not like the old days when liners were rebored and the steps were about .010" between sizes.

Either A or B would be OK. Use A if you're worried about it.