Drive side oil seal - a pain but silver linings present!

[Donnie]

So, mates indian GP, been faultless for about 5 years since it had new bearings and italian race crank fitted after being run in. Literally never ridden in anger and has mainly done local runs other than 2 nationals in that time. Only modifications a reverse cone clubby.

So, it's apparantly burning a little gear oil, no plumes of smoke at all, no drips on the garage floor, but on topping up, it was shy about 200ml so definitely burning.

So, for a £3-5 seal it's basically a complete strip and rebuild - Boooo!

Silver lining 1 is that one of the lighting coils on the stator plate was starting to rattle loose - fixed
Silver lining 2 was the crank was twisted - fixed.
Silver lining 3 was checking the ring gaps which were beyond spec and obvious from the blowby - new rings sourced.

HOWEVER! Just fitted the rings to the piston, getting everything ready to refit and got two new piston circlips out of my stash to fit and found this! Can't believe I didn't notice the damn thing on disassembly! That'll be a new piston then!

[Toddy]

Whats caused that then ?

[Donnie]

good question, it's an indian 3 ring piston, dunno if they suffered quality issues at any point or not, but there's no scores in the barrel at all, so can only assume either it disintegrated slowly or if in chunks he was lucky enough that they escaped out the exhaust port!

[gaz_powell]

got one the same - 3 ring piston (cant remember what make) - it also hads small bits missing from between the first and second ring groove.

the barrel had slight scoring but nothing you would have worried about and head was perfect

was still running (a bit rough mind !)

[Donnie]

Got another from Bedlams but now having a right pain trying to get the squish right!

Seem to be getting a squish of 1.4mm with replacement standard base gasket and NO headgasket. Which is weird as the previous head gasket was over a 1mm thick!

This is messing with my head LOL

[Donnie]

I've ended up fitting another lapped head plus .7mm headgasket to get the squish to 1.3. Looking at the previous head it had a load of gasket face alloy on it so making it a large squish indeed. I guess the new base gaskets thicker than the old one but certainly didnt feel or appear much thicker at all.