opinions, please - pull the head ? or try to do valve seals with the head on ?

[puttputt]

My second 200m, after some tinkering, is running like a rabbit - tons of power, great throttle response, good idle. But it's smoking quite a bit. As previously posted, since it has a lot of
compression, I'm thinking the smoke is valve seals.

I'm trying to decide whether to try to do the seals with the head
on, with an attachment for an air hose that goes into the plug
hole, to hold the valves in place while I replace the seals.

Or, I can just pull the head.

Which do you think would end up making more sense. The thing is running pretty good = real good, actually. Since I've never pulled the head on one of these, I don't know what I'm up against. I assume I can back out the bolt holding the cam sprocket onto the cam, and get the chain off ( after marking )
and then pull the head with the engine in the frame.

Which way is going to work out better, assuming a limited-knowledge mechanic and a limited ( ie basic tools only ) shop ??

thoughts ?

[Mr. Richard]

theres a better way,,,,,, take some 1/4" rope drop the piston down a little from T.D.C. stuff the rope in the plug hole then move the piston up till the rope pushes up against the valves ,,, then you don't have any worries about a valve dropping out,,, it works great when your done just pull it out and install the plug! ,,,,,,,,,,

[Fuzzy]

Does it smoke just when you start it or its warming up?. Or does it smoke all the time?.

Usally valve guides will leak when the engine is just sitting allowing oil to leak down in the cylinder. If it is smoking all the time then i would guess it is a bad ring.

It is possable to have a good compression ring and have good compression. But still need a set of rings. The best way to tell is to do a compression test on it. Check it once when you pull the plug out. And then put a couple of squirts of oil done the plug hole and try it again. If you see a increase in compression then it is time for rings and a hone job.

[puttputt]

It DOESN'T smoke when you first start it. But after running just a few seconds, it starts smoking considerably, and keeps smoking
during warmup and the whole time it's running, even fully hot.
Surprisingly, at least to me, it's not fouling plugs. At least, not
constantly. It probably smokes a little less when hot than during
warmup.

I guess the first thing I should do is that dry/wet compression test, and maybe check for a plugged oil drain hole on the head. . .
The crankcase beather, by the way, is not plugged.