Hi guys, been looking at a friends crankshaft recently whilst my engine is in pieces too, and I noticed that one of the "crank pin spacers" (the washers that go either side of the big end bearing) The engine was running pretty much fine, but we were just checking everything out and putting a new piston in.

As a result, the clearance to the crankshaft is well outside the specs but the bottom end bearing seems fine.

What will happen running the engine without this spacer? (it's a 400 2-stroke).

It's only for light farmyard use so won't be revved hard or raced... we both wish we'd never decided to put a new piston in now, as ignorance is bliss!

 

if the clearance is outside the alloted specification the crankcase will not seal properly....did you have any bearings replaced on the crank...?

 

Sorry, I thin I've given the wrong idea...

I mean the spacers either side of the connecting rod bottom end on the crank pin, not the ones on the actual crankshaft.

The crankcase seals fine, so I'm sure those ones are fine.

 

If this is out of tolerence i would highly suggest that you get the crank rebuilt.You are talking about the thrust washers.

 

POLARISUK if the shimm washers are worn on either dise of the con rod, its not a good idea to continue running it, even for light work. They are there to stop the rod from leaning over and creating a binding effect, this starts to agressivly wear the crank and the con rod. NOT GOOD. u should also be checking for excessive end play on the crank itself inside the cases, this can cause thos washers to wear . I would get it checked out, crank work theses days is not as limited and expensive as was in the past.. later

 

I've just told my friend the good news that he need his crank rebuilding and the quad is going to be sold soon, so it's being advertised ASAP!

Thanks for the advice guys.