gs 850 high idle

[mikesbikesmichael]

well i have looked through the posts and i have to first say what a great website. Now to my problem. I have a 80 gs850 and have cleaned the carbs, taken all the way down dipped and put together with all new o-rings. All the jets are clean and it appears to be properly put together. My problem is that the bike will start right up and run great untill it gets warm. After about 5min the idle will increase to about 5k. It sounds to me like a vacume leak so i installed new o-rings on the intakes and inspected the boots which were good, no help. The thing that has me baffled is the bike will run ok with the air box removed or if i create a vacume leake by opening the port for the fuel petcock it idles down. So i guess my question is if it were a vacume leake shouldnt adding more air make the idle even higher? any help would be wonderfull thanks.

[BassCliff]

Greetings and Salutations!!

Hi Mr. mikesbikesmichael,

Gee, I don't know what's going on. Did you reassemble the carbs properly? Have you adjusted the idle set screw? Did you make sure the new float bowl gaskets have the proper passages punched out? Are there any holes in the diaphragms?

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[nert]

sounds to me as if the 4 carbs are very poorly syncronized to each other. As you search the forum, you will learn you need to syncronize them with a special gauge(s). At the very least, you need to manually bench syncronize them. You should adjust them all so that a (lets say 1/8" drill bit) passes between the each throttle butterfly and the bore, using the drill bit like a feeler gauge. This would indicate that all (4) carburetors are roughly having an equal throttle position at the same time. where is your location?

[mikesbikesmichael]

Thanks ill try the sync i didnt mess with the settings so i didnt think i would have to worry about it. I have a good motion pro sync stick that i will use if i can get the idle down.

[mikesbikesmichael]

well i bench synced the carbs and it didnt help still the same issue, bike gets warm and the idle just climbs. could it be bad diaphrams on the slides? how would you test them? Im out of ideas. I did check the valves and they seemed to be ok, I couldnt belive how tight the tollerance were like .03-.08mm. my smallest gauge is .038 and it passed under all the intakes.

[BassCliff]

Hi,

The diaphrams have to be removed and visually inspected for pinholes or tears. Did you also check the exhaust valve clearances? Did you use the procedure on my website? DO NOT turn the motor if there are any shims missing or you will damage your cam lobes.

Did you also replace the intake boots? Are they old, dried out, cracked? How about the boots between the airbox and carbs? There should be no air leaks in the intake system. How about the boot clamps? Are they all tight? Is your airbox sealed with new weatherstripping? The same goes for the air filter cage. See my website for more details.

Are you sure the carbs are clean? Some members have had to clean their carbs two or three times to really get them clean. Keep us informed.


Thank you for your indulgence,

BassCliff

[mikesbikesmichael]

I should have been more clear all the clearences are ok, i used the procedures from a service manual. All my boots are in good shape no cracks, and not loose. The carbs are clean i have double checked. The bike starts right up and runs great so i dont think it would be dirty carbs. I visualy inspected the diaphrams and i didnt find any holes or tears. My airbox seals are all in good shape no tears or cracks. All my boot clamps are ok not bottomed out. The only thing i could see wrong were o-rings at the top outside of the diaphrams seem to be alittle flat. another thing in a earlyer post someone mentioned the corect hole is the float gaskets being punched out? I did not replace these gaskets so is it possible that they werent installed corectly before? Which holes would need to be open? Also there are small little o-rings in the float bowl gasket area, not the pilot plugs but actuly in the float bowl, these are not in the best shape what do they do and could that be the issue?

[mlbfish]

I feel your pain. My 82 550L does the same thing. It starts and runs perfect until it gets real warmed up. When it is warming up it idles at around 1100 RPM's. Then after a few minutes of riding the idle will often stay up around 3 grand. Some times it will idle down. If I find my problem I'll let you know. I'll be watching for your fix also.