Smoke from left exhaust at start up from cold

[gshead]

I have an 81 GS650G,18000 miles. When the bike is started from sitting overnight, there is a lot of smoke from the left exhaust. It clears up after a few minutes and then no smoke during riding. It doesnt smoke when restarted after the engine has recently been running. All of the spark plugs look good except for #1, its black.

Would I be correct in assuming that the valve stem seals at the #1cyl are bad? Are the difficult to replace? Thanks

 

[Guest]

Hi, I think you are probably correct about the seals, if they are the original they are most likely very brittle by now. Replacing them requires removing the head and disassembling the valves, quite a bit of labor but not difficult. Doesn't sound like a problem with rings since it only occurs on cold start, but it is still a good idea to check the compression to double check. Would be a pain to do that much work and then discover something only a little more involved than the seal work. Ray

 

[Guy]

Is bike parked on sidestand?
Oil is pooling around the inlet valve on number one cyl getting past the valve guide seal(s) and burning away quickly once the motor's running.
Not uncommon and not a big deal, but ya need to pull the head to sort it, and that means gaskets, o rings, oil seals, valve lapping etc. If compression is good, and it's running ok, I'd live with it.

 

[gshead]

It Is parked on the sidestand, I may try parking it on the centerstand and see if the problem clears.

As far as changing the seals, isnt there a way to pressurize the cylinder with air so the valves wont fall?

Thank you for the info.

 

[Guy]

Haven't tried it myself, but I've heard of it being done that way.

 

[CincinnatiKid]

i'm experiencing this same issue on my 81 1100E. just started a few weeks back.
cylinder 1 has some smoke coming from the exhaust header joint, and it clears up once the oil (i assume) burns off.

1) i guess i need to look closer at my exhaust header gaskets and seals, though i have a aftermarket racing exhaust with the springs and slip fit, so it's not a particularly robust air seal.

2) valve guides were replaced back in april 2019, about 1.5 yr ago, by a reputable shop outside Chicago. seems like the valve seals should have lasted longer than this. i typically do all my own service work, but had them do new valve seals and springs while they had the head and cylinders for a recut/hone job. is this an appropriate situation to try and ask about warranty? not that any was expressly indicated, and i don't want to seem like an entitled problem customer, but i wonder what the shop would say if i brought it to their attention.

 

[gustovh]

Is the smoke white or blue. White..water vapor, blue..oil.

V

 

[CincinnatiKid]

thank you gustov.
i would see this smoke coming from the engine on startup, and only since it's been cooler in Chicago. almost always, i am on my way somewhere and don't have a lot of time for careful observation. yesterday i fired it up from cold and took some video, turns out it's white smoke. must be condensation in the cylinder, perhaps from a valve being open while sitting?

curious as to why i only see it on cylinder 1.... but perhaps cylinders 2,3,4 are just making a tighter seal at the header flange, and any white smoke is coming out the tailpipe.

 

[bwringer]

Chances are that it's just completely normal and completely harmless water condensation.

Over on the V-Strom forum, there's a rash of similar posts every fall from new V-Strom DL1000 owners. "OMFG I need a new engine! There's SMOKE coming from the LEFT SIDE?!!!??!?!?!"

Water is a normal product of combustion. With the bike parked on the kickstand, condensation collects on the left downhill side. On many bikes with dual exhausts, you then get visible steam exiting the left side. After a few minutes, the exhaust system warms up enough that the water can't condense and the visible steam goes away. It's more pronounced when the bike is cold, like a chilly fall morning.