22 replies to this topic

[ckendall]

The numbers on top of the piston were 21251+.060 if thats any help

[MRA]

With the pistons about mid way up/down the bore is there a lip at the top of the bore, ie if you run your finger up the bore does it suddenly deviate.... if there is a step then work may need to be done if not then I presume this engine used to run ok so what has changed ??

[Ethel]

The piston size is the bore size really, so you can measure the bore above the pistons with a bore gauge. If it's worn you wouldn't even need to know the size, it's extremely unlikely they'd wear evenly. Since it wasn't new I suppose there's the possibility that it was put together with second hand pistons.

Then again it could be any number of things, failing big ends rob power and rattle.

[ckendall]

I've just checked the bores and they all seem smooth all the way up ???

As for what changed no idea I bought the lump second hand it runs fine at tick over theres just no power when under load
and theres the rattle from the bottom end ??

[MRA]

rattles from the bottom end are never good news

[ckendall]

i know. Looks like I'll be taking the block out and sending it off to be looked at

Any idea of cost ??

[AndyMiniMad.]

Regrind on the crank £80-£90 and new shells...£60-£70. so £150...roughly...But you will need to take it apart and rebuild it yourself for that....If your sending the block away then I guess it would be wise to phone around and get some quotes..I think there is a phone number not that far away^^^^^^^^

Edited by AndyMiniMad., 16 September 2011 - 11:53 AM.

[ckendall]

Thanks Andy I'll be giving the above number a call soon