I seized the RG at a test day on friday.
I Have taken the barrel off and determined it was the piston.
I have an old used but ok high kays piston I will prob put in for the next race while I sort a more permanent fix but I don't want to fuck that with whatever condition caused this still existing.
The powervalves look ok, they had a wee bit of what was probably sicky aluminium on them but no signs of impact or damage, just the bad wear that was there before. (its a bit flogged out)
I was initially worried it was powervalve related because I have been pissing about with them for ages trying to cure all the play in the pulley system from it being worn out, I thought I may have gone to far and made them drop too much.
I had previously thought this was impossible because the fork but that lifts them doesn't SEEM to ocate them and even with it disconnected they seem to stay in place.
Anyway, powervalves are probably clear of guilt coz they look fine.
What seems to have happend is the piston is munted and seized to the bore, it happend once and I let the clutch back out gently once I had slowed to walking speed and it must have broken a weak bond the piston and wall had made.
Gave it another blat. (Yes I know that was silly)
Bang, same thing happened.
Broke loose again too.
This time it has got thru my head that it really ain't right.
The piston and rings were relativley new, inserted into a standard bore that was measured to be within limits.
They had been gently broken in over time and altho still quite new have run fine in two meetings.
The air was COLD - It hailed just before I went out .
The bike was warmed up but not as much as it would normally get sitting on the dummygrid before a race.
There was plenty of oil in the tank and the oil was getting at least as far as the pump.
It has marks good and propper all around the piston, the main one where it has even rubbed over the rings is on the inlet side near the pegs.
The pegs are still in place.
So my Questions (finally!)
What is likley to have caused this?
Could it be that it was just too cold for such a constant thrashing and the piston expanded much faster than the bore?
Is the situation above what a "cold seize" is?
Am I correct in thinking I should warm it up much more now!?
Was that a stupidly lengthly read?
Bookmarks