Poor performance/too much fuel

[motorman]

Hi guys, It's me again, from N.E. Ohio, and in need of advice. I finally got my ignition problem cured by pulling and cleaning all of the yucky green crap from a lot of spade type connectors. Starting, either cold or hot, is nearly insantanious, and all electrical devices, except the low fuel warning light work very well.

My problem now seems to be a "rich" condition that I'm not sure how to attack. I'm getting what we used to call a "loading up" condition when I was still building race cars. This is when excessive fuel is dumped into the engine causing it to stumble or bobble until such time as increased RPM's will clear the cylinder. I am experiencing this condition between about 2000 & 2500 RPM's, and again between about 5500 & 7000. From 2500 to 5500 it performs flawlessly, and over 7000 it simply screams.

Spark plugs are pretty black arount the end of the shell, with #1 being the worst one of the four cylinders. I also seem to have a slight raw fuel smell at idle, can't smell it at speed.

Floats are all set at 1.020 and the needle clip is in slot #3. Since I prefer to only make one change at a time, what should I change fiirst? Lower the float level some, or drop the needle valve a notch?

[Snow]

What year and model is this bike and carbs? Are you running stock jets? Any exhaust or intake mods? Have you installed any carb kits, specifically, from K&L by chance?

You might consider adding your bike to your signature so you don't have to restate it everytime you have a question

[HobbyMan]

maby crank the idle mix screws down a bit

[Snow]

Originally posted by HobbyMan
maby crank the idle mix screws down a bit

Heh, I'd avoid saying it like that - cranking something down usually implies using force and any force will probably destroy idle mixture screws very quickly

[motorman]

Sorry about the lack of information. Here is what I have. !979 XS1100 SF - stock carbs and jets - individual aftermarket air filters - Mac 4 into two exhaust - Accel spark plug wires and coils from an '85 (I think) Gold Wing. Steve

[TopCatGr58]

Hey Motorman,

I'll play, even though I'm no carb/tuning guru!!

I'm surprised that you are getting a rich condition with both Indy filters and aftermarket pipes with stock jets??

However it does bring up the question about your Indy filters and whether they have that prominent lip around the inside where they mount to the carb??? IF so... that could be a big source of your problem. But, if not, then I would look at the float height first.

The first lag is very near the transition zone from pilot to mains, but the second one is harder to explain? Folks with the restrictive Indy filters reported problems around 5-6K or above.

Also, how's the vacuum and cent. advance and timing plate working? I don't remember what rpm max advance occurs? But perhaps the timing weights/plate is sticking??

The transition at lower rpms could be adjusted by lowering the slide needle a notch so that it should require more rpms before the slide raises to start providing so much fuel.

Okay, that's my stab, now let the real tuning gurus chime in!
T.C.

[pggg]

Moto, if there's even tiny, barely visible specks of debris on the float valve surfaces, you're gonna get a richer than normal condition when warmed up and running, black plugs and raw petrol smell are the usual symptoms of float valve problems too, just the usual carb strip and clean might fix things, but new fuel hoses wouldn't go amiss either if you're getting debris in there

[motorman]

Once again, thanks for your input. I am leaning toward lowering the float level some, about .020". and then test again. I will try to get that done tomorrow and let you know the results. Progress will be slow, since I work out of town 4 days a week, and volunteer at "my" boat on Saturdays.
If any of you are ever in the Cleveland area for a few hours stop and visit my boat on the north coast. For a preview of her you can go to www.usscod.org . If possible, I would be glad to show you through her. Steve.