It was head gasket time on Saturday... the 450 has been weeping from there for a while and I was intending to replace it next service, however last weekend on our big ride it nearly let go altogether and I had a brief loss of compression in the left cylinder
I've re-torqued the head nuts on a few different occasions but it didn't help.
Everything looked pretty good when I tore it down, although there is some white caked on powdery stuff on the right exhaust valve which I'm 99% positive is ethanol related. Shell have stuff up there 98 octane about three different times and put ethanol in it and I've been in a couple of situations where that was the only fuel available, and I'm pretty sure I got some the way the bike ran on it a few times.
It may not show up terribly well in the photos, but you could definitely see where the head was wet with oil at the front and particularly the left side.
I expected the gasket itself to be brittle and falling apart but it still looked ok, just doesn't do a good job of keeping the oil in... and again I could see where the surfaces were wet with oil when they shouldn't have been:
Got out my new genuine gasket (still kicking myself for not doing this in the first place), cleaned all the gasket surfaces up and cleaned off some of the carbon (not a lot built up) and got it all back together with everything torqued up properly.
I also checked compression in both cylinders with the new gasket (150 yay) and re-sync'd the carbs as well.
Took it for a short test ride yesterday and while it wasn't far, I did get the rev's up as much as I could and so far all is oil tight.
Oh, incidentally, the motor has less than 28,000km's on it since the rebuild, so no way should a head gasket have gone in such a short period of time!
Comment