Piston Play?

[SupsChad]

Back again to hopefully ask one last question so here we go. In this video here (LINK), you can see the piston has a fair amount of side to side play. It does not have any up/down or angular movement. I know the piston wont move like this in the cylinder, but from previous questions I have asked here, I have been trying to find the source of a "knocking" noise (LINK). So I would like to know if it could possibly have something to do with this. I honestly think this is fine but better to ask now then taking the engine apart again.

To be specific, the bike is a 1982 xs400s heritage special SOHC. I couldn't find any specs for this play in the manual on either the DOHC or SOHC versions.

 

[Berniesxs]

As far as I know that's normal enough. It's just the piston sliding back and over on the gudgeon pin. As long as there's no circular movement which would mean the pin was worn. Mabey someone will correct me.

 

[xschris]

Piston, pin and ring gaps/tolerances are covered on page 120 of the haynes manual. The actual yamaha shop manual would get more in depth with this stuff. https://www.ebay.com/itm/144023585764?hash=item21887983e4:g:B2oAAOSwQTJgigfq

 

[SupsChad]

Ok thank you