GS850G 1981 with runaway throttle... scary.. whats wrong with it?

[jsandidge]

Maybe there is a member who is close to you that could loan you a carb synch tool, or maybe even help you use it and set the mixture screws. Why don't you put your location in your profile so it will appear in the upper right corner of your posts?

 

[04colyZQ8]

Maybe there is a member who is close to you that could loan you a carb synch tool, or maybe even help you use it and set the mixture screws. Why don't you put your location in your profile so it will appear in the upper right corner of your posts?

Great idea! Will do! I'll post up a generic oring size soon at Fluid seal

 

[Nessism]

If you dig through the archives the O-ring size is already there. You just gotta go find it.

Here is the info. It took me 1 min. to find...http://www.thegsresources.com/_forum/showthread.php?158099-o-ring-for-inlet-manifold

 

[Guest]

What ever.... way to discourage someone???? Go back to a time were you started working on bikes? And think of how this might have made you feel? If you have nothing good to say?? Maybe don't post at all?

Please have understanding for someone trying to learn a forum, and learn motorcycle mechanics at the same time!

I'm not trying to discourage you, I'll apologize for that post. But you seem to be ignoring or double guessing tbese guys and they know their stuff. Take their advice and you will not be dissapointed.

 

[04colyZQ8]

I'm not trying to discourage you, I'll apologize for that post. But you seem to be ignoring or double guessing tbese guys and they know their stuff. Take their advice and you will not be dissapointed.

Thanks accepted, and I understand, I'm following instructions now

intake orings replaced, float level adjusted, carb thread read, followed to the t! Pilots out 2.5 turns.

remote mounted gas tank, drilled out 4) 10-32 screws as nipples I installed in boots, 4) vacuum gauges disasembled them, Calibrated the gauges to each other looped lines and pinched with zap straps, unitill readings were smooth and not bouncy.


Adjusted the throttle stops matching them to carb #3. They are within 10% of ones other really close now, they were out for sure!

Adjusted pilots in 1/4" rpm lowered, adjust out 1/4, no change, 1/4 out again, Rpm rises, turn back 1/8 turn seems happy, carbs still in sink.

Adjust idle to 1200 rpm.

cant wait to test ride!

 

[Guest]

Good deal, man. Enjoy that bike.

 

[londonboards]

Sorry to hijack this thread but I have a question for Nessim regarding his comment about the pilot screw:

"The mixture screw setting is relatively unimportant. Just set them to 2.5 turns open from lightly seated and call it done. They only affect mixture at idle and tip in."

I'm always confused about the effect of the mixture / pilot / air screw. I've seen these diagrams and always assumed that even though the overall effect on the mixture is quite small (which affects the engine disproportionately at idle) it would still have an effect on the overall mixture as follows:

But since most of us only really use up to 1/4 throttle turn in normal everyday travel, the adjustment of this piece of the carb system is most critical.

Or have I missed something?

 

[04colyZQ8]

Interesting it apears to have an effect, all be it small but even at wot?

Sorry to hijack this thread but I have a question for Nessim regarding his comment about the pilot screw:

"The mixture screw setting is relatively unimportant. Just set them to 2.5 turns open from lightly seated and call it done. They only affect mixture at idle and tip in."

I'm always confused about the effect of the mixture / pilot / air screw. I've seen these diagrams and always assumed that even though the overall effect on the mixture is quite small (which affects the engine disproportionately at idle) it would still have an effect on the overall mixture as follows:

But since most of us only really use up to 1/4 throttle turn in normal everyday travel, the adjustment of this piece of the carb system is most critical.

Or have I missed something?

 

[Nessism]

Do an experiment for yourself: try setting your pilot screws at 2.5 turns open and go for a ride, then reset them at 2.0, 3.0, 3.5, and see if you can tell the difference. The biggest thing most people will notice is the smoothness of the idle. 2.5 turns open will provide a reasonably good idle for most bikes. The proper way to tune these screws is with the engine fully warm and then tweaking them until you achieve the highest idle speed. They will have a small effect just off the line too.

 

[04colyZQ8]

I just rembered something important! The seal between the air filter and box foam gasket is gone, can't find one anywhere, not sure what to do? Side rubberfrom box to chrome cover is also in poor shape! Right side muffler is blown! Non of these parts I can't find!! And it was running perfectly up untill last week?

 

[Nessism]

There are all kinds of older threads in the archives about how to repair the airbox foam and the foam on the air filter. Voids in any of these seals will affect how the bike runs.

Maintenance is a good thing.

Two different links that provide info about weatherstrip foam...http://www.thegsresources.com/_foru...-How-does-the-filter-seal-to-the-airbox/page2

http://members.dslextreme.com/users/cbsaunders/gs/air_intake_repair.pdf

 

[04colyZQ8]

Ok new plugs, gaped .30" new wires dug out ones, epoxied in new ones, in a spare set of coils, new Ngk plug boots, oil and filter change. Cleaned air filter with kn kit. Used weather striping sealed up air box, spent over an hour getting the bleeping boots which were new last year, onto the carbs they keep slipping off? They need to be 1/4" longer so frustrating! Anyways it's sealed as good as it will get!

Re balanced carbs.

Still high speed Miss at wot!!! So ****ed I want to light the bike on fire, I'm so lost!!!!!!

It sounds sorta low and clacking at idle, like or needs to be leaner? And or carb balance isn't perfect?


That being said since I'm having trouble at wot, I don't think ballance matters? What controls fuel at wot?

In any gear at wot, exactly at 8500-9000 rpm I get a dead miss, like someone yanked all 4 plug wires off at ounce, lean miss? Then it comes back and I accidentally over rev to 10000, it acels clean and so fast from 9000-10000, I usually never go past 9000, but the buck throughs me, I respond with holding it to long when it comes back.

Tell me what jet or office to drill out, somehow I think it needs more fuel! Do I try the pilots at 3.5-4turns? That should give more fuel? IM at 2.5-2.75 turns now

 

[04colyZQ8]

Valves were shimmed 5000kms or 3500ish miles ago, and ran great cleanly acelled to 9000 rpm, I'm confident it's not valve or motor related, I'm allmost 100% positive it's carb fuel related!

I had the run away throttle, pluged jet or vacuum leak, that's fixed but now I created a lean Miss at wot?

My next plan is to try another carb set. I have one off the same year bike. It's not as nice?

Only other thing is the right pipe mufflers loose and blown inside, but it's been that way for ever, and still ran great!

 

[londonboards]

Blimey have some respect for the old bike. These things aren't drag racers. The machine is trying to tell you to back off a little. Next time you hit 10K rpm expect some parts to drop out. Besides you are likely to come off driving at WOT.

 

[Steve]

Valves were shimmed 5000kms or 3500ish miles ago, and ran great cleanly acelled to 9000 rpm, I'm confident it's not valve or motor related, I'm allmost 100% positive it's carb fuel related!

Not that it will fix your problem, but Suzuki recommends checking valve clearance about every 5000 kms.

As others have mentioned, it's not a race bike. You don't need to hit 9000 RPM to get best performance out of the bike.

Since you are just about at the point of setting fire to the bike, I was going to express willingness to relieve you of your problem, then I realized you are talking in "kilometers", so are likely not within a practical distance to do so.

Nothing needs to be "drilled out". Yes, it might seem to be fuel related, but misses at high RPM can easily be ignition related. You say you replaced coils, wires and plugs, what about the pickups and the ignitor?

.

 

[04colyZQ8]

Not that it will fix your problem, but Suzuki recommends checking valve clearance about every 5000 kms.

As others have mentioned, it's not a race bike. You don't need to hit 9000 RPM to get best performance out of the bike.

Since you are just about at the point of setting fire to the bike, I was going to express willingness to relieve you of your problem, then I realized you are talking in "kilometers", so are likely not within a practical distance to do so.

Nothing needs to be "drilled out". Yes, it might seem to be fuel related, but misses at high RPM can easily be ignition related. You say you replaced coils, wires and plugs, what about the pickups and the ignitor?

.

Yes I should take it easy on her, I don't allways rev to 9000, but occasionally I do and it was fun when it ran good!
I'm wondering about the rectifier or some kind of ignition problem? I'm going to sound automotive here... I'm better with a lap top... if it was my truck I'd retard spark and give more fuel at wot, on my laptop. Is allmost like I'm hitting a rev limiter? Do these even have one? I've hit 11000 ounce before when it ran good, schooling Harley rider

what's common to go on the ignition? What do I check? I do have a clymer to help me as well, but you guys know common problems.. like I do for gm v8s and Colorado canyons.... not so much when it comes to old bikes

 

[Guest]

if the rubber plugs below the main jet are loose, missing or in the wrong location it will run like you describe.

 

[04colyZQ8]

if the rubber plugs below the main jet are loose, missing or in the wrong location it will run like you describe.

They are sorta loose and dry, didn't come with the kit were to buy? And what a pain to take the carbs off again

 

[Steve]

If you think THOSE carbs are a pain, you had better not look at any other GS, because you have the easiest ones of the bunch.

At the other end of the "pain" list would be any of the 550s or the '80 and newer 16-valve 750s and 1100s.

Seriously, you can have the carbs off your bike in about 5 minutes, and get them back on in another 7 or 8.
Yes, that includes loosening and tightening the airbox and throttle cables, too.

.

 

[jsandidge]

If you think THOSE carbs are a pain, you had better not look at any other GS, because you have the easiest ones of the bunch.

At the other end of the "pain" list would be any of the 550s or the '80 and newer 16-valve 750s and 1100s.


.

Ain't that the truth. My 850 is a breeze. The carbs on the 750E are a pain, but even worse is the airbox.