Forum

[Felix]

Just went to install new US-made Robbins piston and fresh-bored cylinder.
The only crown mark is 040 near one valve recess. Does it matter which way round?
No mention in the instruction label.
Thanks.

[ric]

No difference in valve cutout size or the presence of gudgeon pin offset ?

[Rattlebattle]

The closed end goes at the top....

[Alan R]

------unless it's an OE piston, in which case it'll be open at both ends, eventually !!

[Felix]

That's why I'm replacing that stock lump.
Still, I miss riding my bike while awaiting machine work. This is my sole bike, and I can see a role for a cheap and (hopefully) cheerful Sportster.