80 GS1000 eratic idle

[Guest]

Hey to all. I have been struggling with an erratic idle for some time now. I cleaned the carbs and put new jet kits in them and put them on the bike. Runs great, it just wont idle consistently. If i set the idle high enough to keep bike running after i ride it wants to run at 3000 to 4000 rpm. So last winter I pulled the carbs again and replaced the butterfly valve shaft seals and put them back on. Same problem. I did find that the number 3 carb was not letting fuel through because at idle the #3 exhaust pipe was cold or colder than the others. So I pulled the carbs again to see if the slow jets were plugged. When I took them apart I found the #2 idle mixture screw was stuck. So I put brand new boots on the head using some honda bond to make sure they seal and put new airbox boots on the carb box. I put a spare set of carbs I had already cleaned and rebilt on the bike. When I synced and colortuned the carbs it idled fine. Took it out for a ride today and I am still having that same idle issue. I did check the diaphram on the slides and non of them have pin holes. So now im looking for any ideas where to continue troubleshooting this issue. I am at a loss as to why my bike just refuses to idle. I did go through the valves 1800 miles ago. So any help would be great

[Nessism]

Pilot screws should be at least 2.5 turns open.

Vacuum sync carbs.

Intake boot pipes sealed w/new O-rings at the head. NO junky sealer allowed.

Airbox to carb connection must be air tight. Get new airbox boots as needed. When you install the carbs to the airbox you must make sure there is no way for false air to enter the system.

An OEM air filter should be used inside the airbox. Airbox lid needed.

All jets in the carbs should be the original Mikuni parts. If you buy aftermarket they may or may not properly match. At minimum, compare the jet numbers against the OEM jet sizes in the factory Suzuki service manual.

Last thing is to make sure your petcock is working properly. Use clear tubing on the vacuum line to make sure there is no leakage working it's way backwards down the line and into the engine.

Last last thing is to check the Newbie Mistakes thread and Carb rebuild tutorial linked in my signature. Hopefully all items are know and addressed, but if not...

Oh, and if you have modified the bike with pod filters, header, or similar, all bets are off.

[blowerbike]

he stated that he installed jet kits..
did he?
or is he calling carb kits jet kits?

[bomber737]

The carb kits I installed are the same ones I have installed on 8 other sets of GS carbs I have done this year. They consist of float bowl gasket, new pilot jet, main jet, air compensation jets, fuel needle and seat, slide diaphram needle. My carbs are the only ones I have had a problem with, all the others have idled perfectly. Colortuning is for setting the idle mixture screw perfectly. I will be redoing that tonight to make sure they have not changed when I synced the carbs. The intake manifolds are brand new oem and the o-rings are to, I got new clamps with them. I put the honda bond to make sure there is an air tight seal. Thats the point of that stuff, remains flexable when cured and seals gaps and does not degrade with fuel exposure. I got brand new oem airbox manifolds also and new clamps. The air filter is new this year. The bike is completely stock. I replaced the rubber joint last year between the airbox and air divider. The only part I reused was the air compensation jets. The jets in the carbs were 190's and the jets that came with the carb kits had 170's and 200's so I cleaned them and stuck with the original ones. I looked at the spread sheet from bascliffs site and there is no specific air compensation jets size listed. I also checked the pilot and main jet size listed. unfortunately my bike is not listed in the spread sheet so I used the numbers from the 81 GS1000EX. All those numbers matched what I pulled out of the carbs. 40 pilot and 107.5 main jet. It probably depended on the flow rate of the carb with thich one they used. I got this bike from the original owner and he only put 3700 miles on it so I know these carbs had never been removed before I cleaned them. I am running a Pingle pet cock so I am not using the vacuum from the #2 carb, I have it blanked off. Your right, I miss spoke. i said jet kits and I meant to say carb kits.