I’ve just rebuilt a Montesa engine, but I seem to have a lot of end float on the little end/piston.

The little end bearing fits exactly between the bosses on the piston but there is a gap of about 2mm each side of the rod eye?

I’ve normally found the bearing is as wide as the rod and there are thrust washers, but its impossible to fit thrust washers due to the width of the bearing  

 

I think, if i understand your story well, thats normal/ The small end bearing you mean?

 

The piston should ''find'' its good direction, but its in a barrel so no problemo, and does not need to be forged into the correct place or so.

Edited June 9, 201511 yr by crazybond700

Thank you, thats what I was hoping

some montesas locate the rod centrally using the little end and some use the big end. Cota 348 is one that uses the little end of the rod. If that is your engine, 2mm each side is way too much and you should use a narrower bearing and spacers.

Hard to help more because you didn't say what Montesa engine you rebuilt