White smoke

[madoc]

1980 XS650G. Pretty much standard.

While running down a long hill, with plenty of twisties, my girl and my mate (behind me on their bikes) alerted me to the huge amount of white smoke I suddenly started generating.

Back home, the smoke seemed to be mainly on one side.
I did a compression check and found 150 and 155; so I assumed valve stem seals.

I found the method of changing the seals, using a little tool, on the various XS forums.
It took four hours (including making up the tool and running out for some tiny pliers) to change both seals on that one side, but it looked like problem solved.

..until a few miles out on a run the next day, when the smoke returned with a vengeance. I checked both the seals I put in.. and they are in place, together with the keeper springs.

It also appears to be smoking a little more on the other side now too ...

What else could cause this ?
failed rings ... but compression is fine ...?

 

[TwoManyXS1Bs]

The two other usual suspects are rings and weeping headgasket.
A failed compression test is definitive.
A passing compression test isn't...

 

[Paulrxs650]

Hi Madoc,

White smoke is usually indicative of oil. It sounds to me like rings. A compression test must be done at with the throttle wide open to get the correct readings. Even then, if there is oil passing the rings, that oil will create an effective seal, giving a misleading reading too. If you can, kick the bike over a few times with the plugs out and then get the piston near the top of its stroke and have a look in through the spark plug whole with a torch, or better still a bore inspector. If you can see oil congregating where the piston meets the bore wall, its looking more like rings - either cracked or worn out.

Paul

 

[madoc]

Update

I did some searching and reading.

My oil level was a little too high ...drained some but with no effect.
However, when I went to retorque the head nuts, I found them very loose. I torqued them back to the slightly higher spec, given elsewhere on this forum, and saw an immediate improvement.

I think I now need to ride and see whether we're now clear.

i retorque on my British bikes, ŵith solid copper head gaskets. they can start leaking and be sorted like that too. Dunno the situation with the xs head gasket .... I guess I will see.

 

[Paulrxs650]

Yep - a retorque ccan cure these bikes too - happy riding