Carbs - leave them or tweak some more ?

[Guest]

OK Guys - I would like some GS opinion -

I've got an '83 GS1100ED, 4 into one header (unknown brand), and Stage 1 dynojetted carbs, mixture screws 2 1/2 turns out, with stock airbox.

Bike carburets well, when I start it up cold I have to work the choke for a minute or so to warm it up, throttle response is great, and it pulls hard to redline, even in 5th gear, which is insanely fast -

BUT - after a 30 minute ride down I-90, fully hot, the idle speeds up from 1000 rpm to about 1200 rpm, and there is a wisp of blue smoke from the pipe at idle, like it's running a touch rich.

And when I'm cruising along at 30 mph, in 3rd, and back the throttle off all the way and coast I get a little popping -

So what would you do - leave it alone, tweak the mixture screws, or something else ?

I'm leaning towards leaving it alone, because the thing is a real motor beast - runs strong.

Whaddya think ?

[7981GS]

Rich is always better than lean.
I would turn the mixture screws in just a tad myself.

Daniel

[hampshirehog]

You're symptoms are slightly contradictory. The rising tickover would normally indicate lean whereas the smoke normally indicates rich. Does it smell of petrol when you're just pottering around - approx 1/8 throttle setting, say 30-50 mph in top gear?

[rapidray]

FIRST, did you set your mixture screws to the "fastest idle" method? First, do that & then ride it again. If you are unsure of what that entails, call me at 714--356-7845. If the popping on decel is still there, put ONE shim under the needle clip to raise the needles 1/2 a clip groove position. Also, are the float heights all correct? Get back to us after these things. Ray.

[Montanaman]

I didn't set them to fastest idle - I set them at the 2 1/2 turns as per the DYNOJET instructions -

I was just in the carbs rejetting them down from DJ114's to DJ110's, with the needle in the third position, and the floats were all correct height & uniform.

I haven't noticed any raw gas smell though.

[Oakley]

Carbs-leave them or tweak some more

What altitude are you in at in Montana? I am also in the process of (re)jetting carbs on an 83 GS1100ESD running a V & H four into one pipe and K&N individual pods. I am at ~5000 feet in Colorado (Denver area). It was running a bit lean after carb service at local shop. Also having some difficulty and need to go back through them to recheck everything.

[Montanaman]

3211 ft in front of my house - 3600 ft where I do WOT runs -

[rapidray]

Adjust the mixture screws correctly using the fastest idle method. Ray.

[sedelen]

Blue Smoke, to me usually indicates oil burn, black too much gas.
What do your plugs looks like, carbon wise?
If lean indication I'd probably tweek the air screws out a little, and see
if it improves anything.

[Montanaman]

I just realized that I missed a step by not starting with fresh spark plugs, because who knows how long the previous owner had ridden it one step too rich, so I screwed in 4 new spark plugs, and drove it 40 miles at 75 mph, and it's not running lean - the plugs are running a medium brown/gray color - so Tuesday when I have a day off, I'll shim up the needles as was suggested, and see if I can't get rid of the popping on deceleration.

There is a fair amount of carbon dust inside the pipe, and I just realized that the little smoke I saw could have been from burning off carboned up pipes & combustion chamber.

[Big T]

You need to adjust with the high idle method first