Stalling agian, and agian, and again

[Anonymous]

Here we go -
1981 GS550T, 16K on meter.

Symptoms-

1.Will start right up with choke pulled 3/4's way out, quickly goes up to apprx. 3-4K rpms.
2. Back choke down, can only get idle to stay at 1500 - 2000 rpms (even when warm), under that and bike stalls (ever so slowly, but will eventually die. Will not idle at 1000rpms at all.)
3. Related (maybe) symptom - Turn on lights (especially noticed with high beam, not at all with blinkers) and there is a 500 - 1000 drop in rpms, and as I always run with lights on, is especially troubling
4. Bike has good power, runs smooth, no problem if idle set at 2000rpms.

Have done already -
Cleaned all contacts, checked r/r (battery keeping charge/recharging, used fault finding checklist, system seems good). Changed plugs, tried adjusting idle knob (with engine warm and cold, lights on and off)
Spark plugs show running rich (excessive idleing?), but not fouled badly.
Person I bought it from said carbs done late last year. Ideas include -
Mal adjusted carb's, air leak in carb intakes, dirty carbs, bad connection somewhere I missed. Any help greatly appreciated - I love this bike, will be doing MAJOR overhaul this winter. Just want to enjoy the precious little riding time I have left this season, without having to gun it at the stop lights, or have it idleing at 2000+ rpm's all the time...

Thanks agian!!!! Lost without the TREMENDOUS amount of knowledge here!

Rob

 

[Anonymous]

Choke cable recently replaced also...

 

[earlfor]

I used to have that very same problem. Most likely cause is that a couple of the idle jets are not clean as thought to be and when the engine is idling, it is having to try to run on only two cylinders working. Once you get to a higher rpm range, the idle jets become less important. Once you can get it off choke, if you can keep it running at all at low rpm, put your hands on the pipes and I'll bet you find a couple that stay cold.

Earl

 

[Anonymous]

Thanks for the input!

Looks like a carb cleaning/repair is store for me then..

Would this cause the plug color to show a rich condition?

 

[Anonymous]

A 1 year bike makes you unique! Like having a Harley that won't mark it's spot :twisted: How clean is your air filter? That would give you a rich plug. When it starts to die, whack the throttle open and let us know what it does. Stumble or wind right up? Bob
The lights will affect the idle to a point. Something has to power the light and that is fuel.

 

[Anonymous]

Uniqueness is NOT good from a parts perspective...

Replaced filter element.

Whack the throttle open - For the first minute (and only for a minute) after starting (bike cold), engine hesitates and rpm's drop. After a minute or so of warming up, choke down as far as I can get it without bike stopping,(2000 rpms) bike responds well, rpms climb quickly.

Thanks

 

[Anonymous]

Stock filter? Have you checked all head pipes for even heating?

 

[Anonymous]

Stock filter, new filter element.

Just checked pipes this morning, seems like 2 out board pipes were a little cooler than 2 inboard ones. Could be my imagination..seems wierd though..

Rob

 

[Anonymous]

OK, now we have something to go on. Cylinders #1&4 share a set of points and a coil. Check your spark on these cyls compared to 2&3. If they seem to be lacking, check for 12V at the coil. Pull the connectors apart and clean along with cleaning ground. You may want to pull the cover off from the points and give them a little touch up. Check your point gap. Bob

 

[Anonymous]

Will do this weekend - Thanks for the info. Could it also be the carbs as suggested in an earlier post from earlfor? I will be rebuilding the carbs, so if it is them, I'll be doing it earlier than later...

Thnaks for all the input, much appreciated!

Rob

 

[Anonymous]

It could be the carbs as Earl suggested but having 2 cyls cold/cool would point me in the other direction. Having said that, I've stood corrected before also. Rather than burn hands I hit the pipes with a spray bottle and water or windex to find heat. But then I don't care for heat that well :lol: Bob

 

[Anonymous]

Will try your suggestion first off, then rebuild carbs after, as I will be having bike apart ot have the tank, side covers and fenders repainted soon..-

One last question on this note - any good places to buy the tools I need, to synch/balance the carbs with? Denniskirk, which is where I will be getting the rebuild kits..

Thanks a million..(small bills only, and you pick up - :lol:

Rob

 

[Anonymous]

JC Whitney, Dennis kirk, Motion Pre all have synchronizers. Look around this site for carb kits. Somebody(can't remember name) is selling all orings for 1 carb/$13+/- I can't see spending $25+ bucks on the same kit unless you need float needles and seats. Make sure you get the right adapters for your intakes. 5mm Bob

 

[earlfor]

Other than your rpm, that sounds normal. Its exactly like mine and for sure, for sure, ther aint NUTTIN wrong with my 750.

Earl

Whack the throttle open - For the first minute (and only for a minute) after starting (bike cold), engine hesitates and rpm's drop. After a minute or so of warming up, choke down as far as I can get it without bike stopping,(2000 rpms) bike responds well, rpms climb quickly.

Thanks

 

[Anonymous]

running condition

running condition

Rob,
Beforre you tear everything down ....another "test" you can do to check out the manifolds is spray the area of the manifolds where they attach to the head with soome contact cleaner....if you get a rise in engine idle they may be suspect. My 850 got to where you couldn't sysn carbs no matter how hard you tried....$100. later maniflods in hand problem solved...but its not that easy....for more e-mail me off list....

Rodm850g@aol.com