Smoking on startup

[oicu812]

Just picked up a 1985 125m a few days ago. It smokes abit on start up. Previous owner says it is probably the valve seals. Is this an easy fix? It starts and runs great. The smoke is grayish, not really blue or black. Will I do major harm to the engine running it like this or is it more of just a nuisance thing? Is there a way to test to know for sure if this is the cause?

[arkantrike]

I've had the same problem with my '84 200s for about 5 years now. It started shortly after I bought it. At first I thought "oh, sh!t...I just bought it and already time for a rebuild. I talked to a trusted source at the local Honda shop and he told me as long as it didn't do it after it was at operating temp not to worry about it. The worst thing that can happen is it might foul your plug, but until it does - I would just ride it. Hell, it might even be a bit helpfull! :-D

[arkantrike]

Oh, yeah - it's still on the original motor and going strong. I run Honda GN4 10W-40 and change it whenever it gets good and discolored.

[chuck]

i remember from having this problem on a car it was the valve stem oil seals. when it sits the oil will leak through the worn out oil seals and get in to the cylinder and burn off at first start and then go away untill the next time it sits.

[oicu812]

It doesnt look like the seals cost much, is it a hard fix? All I have is the Haynes manual and it doesnt cover this ( or much else ). Can you tell Im not very happy having to translate "english" into American?

[chuck]

two ways i know of. get a air fiting that will fit the spark plug hole and apply air to the cylinder so you can take the valve spring retainers out with having the valve drop in the cylinder and replace the seals or take the head off and do it that way. i dont think it would be hard with a little mechanical know how.

[plkmonster2]

Also, Make sure that the piston is at TDC, and make sure it stays there. Then apply air, about 120 psi. You need to have something that will hold the piston at TDC. In many cars that we have done, the pressure will spin the motor over. :shock: once you get the spring off, you can put a rubber band around the valve for extra security, although, if it's at tdc, it shouldn't drop in. Good luck. Also, we used a compression tester hose to connect the cylinder to the air pump.

[oicu812]

OK, here's what Ive learned since I posted this question.
1. Theres only one oil seal and its on the exaust valve. (job is already half)
2. Exaust valve is the one facing down so it shouldnt fall into the cylinder.
3. I recalled a post from a while back where somebody was doing valve work. They removed the spark plug then stuffed some twine or cord into the cylinder then moved the piston up to compress the twine so the valve wouldnt slide into the cylinder. I dont have an air compressor to keep the valves in place so this trick may just work for me.
P.S. Dont suppose anybody has a scan from a clymer(or similar) manual with a blowup diagram of the valves/head?