Cold Start White Smoke and Engine Bogs Stutters Stalls when Starting from Stop

[herostar]

Hi GS friends! I have two questions in one, not sure if they're related...

Recently my '81 450e started blowing some white smoke from the shifter side exhaust pipe when I first fire it up from a cold start. After the bike warms up it seems to go away. I park it in a garage in dry colorado, and have searched and found that many think this might just be condensation but I want to get more opinions. Which brings me to my second question...

The bike bogs down really bad when I'm pulling away from a stop, then all of a sudden gets its mojo back once I'm going ~5mph. I've heard this could be an issue with the pilot jets, but I cleaned the carbs out this summer and didn't have any issues for a while until now. Thoughts?

Pertinent info:
Carbs & tank cleaned this summer
Premium fuel only
Stock intake, jets, exhaust
Starts first try, every time (really!)
Idles fine, and comes down to idle fine
Bike does not seem to be burning oil
Valve clearances adjusted ~2500 miles ago (3 yrs)

 

[herostar]

Spark plugs, the one on the left in the pictures is the one on the shifter side of the bike

 

[Steve]

I will just add my comments to your original post.

Pertinent info:
Carbs & tank cleaned this summer
When you "cleaned" the carbs, did you just spray out the jets or did you soak the bare bodies and replace ALL the o-rings?

Premium fuel only
Ditch the "premium" fuel. Your bike will run much better on "regular" fuel. In your area, that is probably 85 or 86 octane.

Stock intake, jets, exhaust
All good points.

Starts first try, every time (really!)
As it should, no surprises there.

Idles fine, and comes down to idle fine
By "comes down", you mean a nice, crisp, quick return to idle when you blip the throttle?

Bike does not seem to be burning oil
That's good, but really has no bearing on your current problem.

Valve clearances adjusted ~2500 miles ago (3 yrs)
Get ready to check them again, recommended interval is 3000 miles.

I did not see any mention of carb sync. If one carb is closed a bit too far, it will suddenly "get its mojo back" as it is opened up a bit off idle.

Cleaning the pilot jets was not a bad idea, but it's not usually the jets that cause the problems, it's the passages in the carb bodies between the jets.
That is why it is important to soak the carbs, not just spray them off.

.

 

[herostar]

Steve, Thanks for the insightful and fast response!

The carbs were soaked, synced, and re-o-ringed by a local shop that specializes in older/classic bikes. When the idle comes down it is crisp and quick, no bouncing or hanging (was doing this before I had them worked on).

Today the bike ran well on my way into work.
What I did in the last two days: full fuel tank of 87 octane no ethanol, added an appropriate amount of SeaFoam to the new gas, drove it a little to get the new gas through the carbs, then let it sit for a day.

As for the smoking issue... it has not occurred in the last couple days. I've been parking the bike on the center stand at night, as someone suggested that the cold Colorado night air was probably condensing inside the hot exhaust and was "pooling" in the shifter side exhaust pipe when the bike is parked on the kickstand. I can't confirm this, but will put the bike on the kickstand tonight to see what happens. I probably won't ride it tomorrow as it's supposed to snow, but I'll fire it up to see what happens!