82 gs850 wont run without choke

[RobC]

Ok quick question before I have to leave for work, I've been tinkering with this bike all morning.

Its a 82 GS850GL that I recently purchased not running. I have torn the carbs down and cleaned them, they recently had a rebuild kit installed but the previous owner didn't clean them well at all. I got the bike started with full choke but when even I try to turn the choke off or open the throttle ANY it dies.

I opened the air screws 1.5 turns, the float levels are within limits, and I did bench sync them. The airbox had some holes drilled in the top for a ghetto mount set up, I taped those up thinking they would allow too much of an air leak but that didn't help any. With the choke on it will crank up each and every time, seems to idle a bit high but not sure how many rpms ( tach cable is broken and new one hasnt gotten here yet)

I am new to motorcycles but I have worked on EFI engines a good bit and my carb experience has been limited to Cessnas, solo updraft carb is easy to work on.

With the choke pulled and running I did squirt a bit of carb cleaner around the boots and carbs with no noticable change in RPMS, so the boots dont appear to be leaking any.

Any ideas where to look next? Sorry if my question has been covered before, I tried to search but probably used the wrong parameters heh.

[BassCliff]

Hi Mr. RobC,

Yours sound like classic lean symptoms. Squirting stuff around the intake boots is not a reliable test. New intake boots and O-rings may be in order here. Do you have a new, lightly oiled air filter installed? Is the airbox properly sealed? Check the garage section here on this website and my webpage for more information. It's all here in my mega-welcome page. Keep us informed.

Thank you for your indulgence,

BassCliff

[Steve]

OK, elaborate just a bit on how you " [tore] the carbs down and cleaned them". Did you take them completely apart, then dip each carb body and its brass jets in Berryman's Carb Cleaner Dip overnight, then rinse it off and re-assemble with all new o-rings? If not, that might be part of your problem. You have already admitted that the previous owner "did not clean them well at all", so you know they were dirty to start with. If you sprayed some carb cleaner on the parts you can see, that's not enough. You have to dip them, and based on your limited description, overnight would be best.

Oh, and your "air screws"? They are actually "idle mixture adjustment screws" and they regulate a mixture of gas and air, not just air. When you put the carbs together, with all new o-rings, set the mixture screws to 2 full turns out, then, when the bike is properly warmed up, you can tweak from there.

And rest assured, your question has never been brought up before.

[psyguy]

i'd start by making sure that the intake boots are soft and pliable, and not cracked
and the orings are in order

your airbox has to be sealed with a slightly oiled filter in it

failing this, yeah, carb-tear-down time :sad:

[joshua]

Hey there, I'm no expert but I've recently been helping my friend get his gs850 up and running again after sitting a while, cleaning the carbs, replacing o-rings + seals and all that. We ran into the same problem as you, it would only run with full choke on, and stalled if we tried to throttle it. It turns out when we did the bench sync, we turned the idle speed adjustment screw(not the idle mixture screws) back down way too far. Whoops. I slowly turned it back up as it was running to raise the rpm's, and slowly eased the choke off to bring them back down - until the choke was all the way off the the idle was somewhere close to normal. Might be worth a shot. Good luck!

[RobC]

Ok I'm sorry for the limited description earlier.

I had soaked the carb's overnight( it wasnt berrymans though) and I did disassemble as per the mikuni repair manual I downloaded off of Basscliff's links (thank you for those). Even after soaking in the cleaner some of the smaller passages were still slightly plugged. At least the gunk was broken up enough that with a can of carb cleaner I could blow out the passages. Then let it soak for a few more hours before reinstalling everything. All the O-rings were still new and pliable so I just reused them when I put them back together.

The boots were also new and installed about 4 months ago, same as when the rebuild kit was thrown in.

The air filter is in good shape(not new though) and I washed it and sprayed the filter oil on it as per the Suzuki manual.

Thank you for the input I'll try both suggestions to see if it makes any difference.

[RobC]

Ok update I opened the Air mixture screws 2 full turns and tightened the idle screw up till it put some tension on the butterfly valves. She ran, although a bit rough I could get it to idle and I'll make more adjustments tomorrow, I ran out of time today. I couldn't resist I did take it for a spin around the yard and made 2 laps (about 2 acre side yard) in 1st before I sat her back on her stand and came in here to get ready for my real job. :-D

Well so far I have gone from a non running junker, to well at least a running junker lol. I do want to thank all of you guys for the info you have put into the site, I couldnt have made it this far without all the great info.

[BassCliff]

Hi Mr. RobC,

Hey! That's good news. Keep us informed.


Thank you for your indulgence,

BassCliff

[Steve]

[psyguy]

troubleshooting other than carbs

rob c, it sounds you're doing all the right things with the carbs, but she's still not running great - i wonder if you have checked the compression yet and if the valves have been adjusted

[RobC]

Ok Steve you want a pic here is the best I have taken of it, just remember the bike is really rough around the edges and you asked for it :grin:.


Maybe I should have clarified running rough a bit better, at idle it was running smooth but would occasionally hesitate when I would advance the throttle. The airbox is leaking some I do know, from the multiple holes he drilled in top for the ghetto mount set up. I had done a quick tape up job just to seal it as much as possible in the effort to get it running. I will make a better mount set up and seal it all up right before I ever try to put it on the road. Also I haven't made any tweaks to the air/fuel mixture yet, just the initial 2 turns out. The guy I bought it from still has the mufflers so I'm only running the headers at the moment. I'm hoping to catch up with him this weekend so I can get those installed.

I'm sure it wouldn't hurt to do the valves, but I have bigger issues I'm taking care of first. I'm trying to do one thing at a time to keep from getting overwhelmed, and my first has been accomplished.

Overall I have about $520 invested in it so far, I guess thats not too terribly bad.