1986 RM250 Big End (Video link)

[LegOwt]

Got a fair bit of sideways movement on this RM250 big end. Latter part of the vid I'm pulling vertically on the piston up and down and not much there which is how we want it but what does everyone reckon on the sideways movement, is that excessive??

https://vimeo.com/112006020

[sleepy]

If you can notice any up and down you are in trouble but the side ways is normal for one of those. If you test the side ways rock it should be less than 2 mm. The rock is the amount the top of the rod can move sideways without the bottom of the rod allowed to move. It is best to take the piston off to do any checking and if you are not sure find a motorcycle engineer to check it out. Sometimes even if they feel ok the pin or rod can be starting to pit quite badly, only 100% check is to press it apart.

[Lozza]

Completely normal with a top guided (thrust washers on the gudgeon)

[LegOwt]

Thanks fellas, appreciate your feedback.