1983 GS550 plugs #1 and #2 fouling out

[Anonymous]

My father let his bike sit in the garage for three years and didn’t start it once. When he did start it he neglected to drain the tank and the carbs. I have since drained the fuel, replaced the plugs, cleaned the carbs (I sprayed all the jets with carb cleaner and compressed air) and replaced the air filter. The bike will run great right after I clean the plugs, ride it for about 30 minutes and plugs #1 and #2 foul up (this model has duel carbs)and the bike starts reving up and will not idle correctly. This is the same problem it was having prior to me doing anything to it when he pulled it out of storage. I also noticed a build up of gas in the air box. I have been doing some reading on your site and I also noticed some of the posts about the petcock position. He has PRIME, ON, and RESERVE. I think he has been leaving it on prime (I know this bike works on a vacume system) and just letting it flow. Where should he leave the position when not driving, and any suggestions about the plugs? Any help is greatly appreciated I am sooooo tired of beating around the problem. HELP!

[Anonymous]

Don't use Prime unless you are trying to get it to fill the carburetor bowls.


Tim

[Anonymous]

I agree do not use prime unless you are trying to fill the bowls.
Leave the petcock "ON" for normal use.

The gas in the air box points to a sticky float needle in one or more of the carbs (#1 and #2 ??) and or a bad petcock.

The fouled plugs are from the carbs running to rich. This could be caused from the above issue, or the airscrew slow jet that control idle to 1/4 throttle. Check the adjustment of these, and make sure the carbs are synchronized.

The ?revving? issue could be caused from having a sticky throttle cable, loose vacuum hose, or plugged journal in the carburetor (or an unplugged journal in the carburetor that should be).

Also be careful when using compressed air with carburetors, you can permanently lodge particles in the carburetor journals, or blow out journal plugs.

[Anonymous]

Personal experience says there's no substitute for totally disassembling the carbs and soaking all the parts, then blowing them out with compressed air...don't forget, the carb bodies have some little channels too.

When you pull the carbs to check for sticky float needles, have a good look at the float needle seats too. We had a bad one, which was letting gas leak around the float needle.

Basically, if you've been leaving the petcock in the 'on' position, and have gas in the airbox, you probably have a bad petcock and float needle valve(s)/seat(s). If you've been leaving it in prime (yep, bad idea) then it may only indicate a needle valve problem.

And, if you have gas in the airbox, chances are you have gas in the oil too...so you might want to fix the problem real soon, and change your oil!

I'd guess the revving and bad idle are more a result of the plugs fouling than anything else at this point, and it you haven't completely disassembled the carbs and soaked them, I'd try that.

Good luck with the gremlins!

[Anonymous]

Um Bikermouse did you read my reply?

Tim here is some more info for you.

idle - 1/4 throttle = air screw slow jet
1/4 - 3/4 throttle = mostly needle clip and taper *
3/4 - full throttle = mostly main jet *

* there is some overlap between the needle clip/taper and the main jet 1/2 -3/4 throttle

[Anonymous]

Um Bikermouse did you read my reply?

Ahh, the written word has failed me again!


Yes Steve, I did read your reply. I was essentially trying to agree with you, while strongly suggesting that he make sure the carbs are truely clean before changing the adjustments.

I was also trying to add the suggestion that his revving issue may be a result of the fouled plugs, not as a result of an additional problem, as we experienced a similiar revving situation while doing battle with carbs that were running way to rich.

Hope this clears up what I was trying to say

[Anonymous]

what are your pilot screws set at, if the plugs covering them have been removed. I need the baseline for my bike (also a twin carb TSCC 550 engine-1986). In the midst of trying to track down a problem they were "asjusted" and now I need to know the factory setting. Thanks all.

Pete