Engine overhaul

Sounds like a good idea. A wiki-style Howto section would be an excellent reference work...

very nice and clear post btw Chris.

Yeah, they reckoned it was all within spec and just honed it, although Walt did mention before about the rings being able to rock, but the gaps were all within spec so it's hopefully all ok

Nice work! Looks like Your engine was exactly like mine. I changed the cam chain as well as a precaution.
Were the valves tight? I had one exhaust leaking badly and a inlet leaking a bit so I had them all recut and lapped.

I did wonder about doing the cam chain but I was trying to do it all the cheap, and it should be good for a heck of a lot of miles yet.
I got the shop to clean the head up and leak test the valves for me and he reckoned they were fine.

Good, clear write-up Chris G.

I've had the top end of my '94 MKII rebuilt twice since last October. Last September the let hand pot blew a chunk of exhaust valve into the header..... After that rebuild the right pot did the same. Second time around most of the valve guides were replaced. Mine's still an oil burner though

For the benefit of myself... The oil consumption is considered to be ring/bore wear?

Nope I'd say this aint so. The few I have peered inside had rings with tolerance and no sig ovalling of bores (mkI's this is).

Mine wasn't just using it, it was burning it. People following reckoned it looked like I was on a 2 stroke when I accelerated. I worked out it was running at 50:1 fuel:oil mix, not sure about 2 smoke bikes that's what most chainsaws and strimmers run on! The usual suspects are apparently the valve seats or the piston rings. The compresion test gave me 1 bar more when I poked some oil down the barrels which is apparently a sure sign of a ring problem as the the oil enables it to make a better seal. It always used oil before it started burning it and I wouldn't mind betting by oil burning problems comes from it being run without enough oil in it at some point.

Due to moving house I've only done 65 miles since the rebuild so no idea about consumption yet.

There's a few threads on the old forum about people changing a seal on the gearbox output shaft (I think) which some claim has stopped the consumption problem and others claim made no difference.

Edited by ChrisG, 10 May 2006 - 07:59 pm.