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

[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/_forum...e-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

[derwood]

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.

[04colyZQ8]

I figured out my 8500rpm miss... bad grounds, not charging! Bike wouldn't restart hot, and then cold cranked over slow, anyway its back to its old self again..better then, its been since I've owned it.

Still has a miss right at 9000rpm I seemed to have moved it up, but I can live with that.

I still need to mess with the mixture screws, It doesn't respond well, your supposed to have the rpm raise or lower, I don't notice much difference? I tried 3-1/4 turns out, and all the pooping on decell went away, but it was kinda boggy. I turned it in a 1/4, still boggy, no decal popping. Now they are at 2-3/4 turn, and it pops a bit but not like it used too, and still seems sluggish from idle to mid range. I think it needs to go leaner still, am I right to assume turning in clockwise leans out the mix? You want pooping on decal correct?? BTW my right pipes baffles are blown to sh*t.

I have a motion pro carb balancer on the way too

[roeme]

Phew, your posts read like they've been written by a squirrel high on sugar.

I was going to recommend to take it a bit easier, do one thing at a time, be methodical, etc., but it looks like you're beginning to do that on your own.

You want pooping on decal correct??

I usually poop only I if I need to emergency brake because someone swerves into my lane...jokes aside, you meant to say popping on deceleration?
I don't think that should happen on a GS with stock pipes.

I think it needs to go leaner still

From what you describe, I'd say so as well...however...hm. Since you have the carb balancer on the way, do the balancing as a next step. If you get rid of the misses, great - but I don't think there's much chance for that. So, if you still have issues, it really is time to have a look at the valves. I saw that you did 5000 km's ago - but as per the manual, that's exactly the interval for checking the valves. So by the book, you'd need to look at them anyway.

I don't say this without reason; my brother's bike exhibited similar symptoms to what you describe: keeps missing at WOT, hesitating and bogging elsewhere. Kept fiddling with the carb, not to much avail (the issues at best just came back a little later). After we finally got the necessary stuff to do the valves properly, it was smooth sailing.

In any case, it's one thing you can cross off the list of things that could be wrong.

[04colyZQ8]

Phew, your posts read like they've been written by a squirrel high on sugar.

I was going to recommend to take it a bit easier, do one thing at a time, be methodical, etc., but it looks like you're beginning to do that on your own.



I usually poop only I if I need to emergency brake because someone swerves into my lane...jokes aside, you meant to say popping on deceleration?
I don't think that should happen on a GS with stock pipes.



From what you describe, I'd say so as well...however...hm. Since you have the carb balancer on the way, do the balancing as a next step. If you get rid of the misses, great - but I don't think there's much chance for that. So, if you still have issues, it really is time to have a look at the valves. I saw that you did 5000 km's ago - but as per the manual, that's exactly the interval for checking the valves. So by the book, you'd need to look at them anyway.

I don't say this without reason; my brother's bike exhibited similar symptoms to what you describe: keeps missing at WOT, hesitating and bogging elsewhere. Kept fiddling with the carb, not to much avail (the issues at best just came back a little later). After we finally got the necessary stuff to do the valves properly, it was smooth sailing.

In any case, it's one thing you can cross off the list of things that could be wrong.

Yes, I can be in a big hurray, and or posting to late at night.. I suppose your right, high maintance theese bikes are, I spend more time working on it then I do ridding it!!

Needs new tires again soon, just put them on 5000kms ago. Anyway I will shim the valves and try to fix the oil breather, and valve cover leaks! I've tried fixing those leaks three times now! One bolt on the breather is stripped. I will heli coil it, and I'm going to silicone the crap out off it, useless oem Suzuki gaskets are not sealing dry!!!! I have never had this much trouble with oil leaks in my life!

I prefer to get the shim tool, and shim kit, last time I removed the cams each time to pull shims, I also made three trips to the dealer getting proper shims! What tool and shim kit to you guys recommend? Are the aftermarket shims hardened properly?

[Steve]

I prefer to get the shim tool, and shim kit, last time I removed the cams each time to pull shims, I also made three trips to the dealer getting proper shims! What tool and shim kit to you guys recommend? Are the aftermarket shims hardened properly?

Some prefer the official shim tool, many of us prefer a zip-tie, it's your choice. I have both, but can never get the 'tool' to work properly and have never been shown by someone who knows how to use it properly.

As for a "shim kit", you will go broke if you buy multiples of all available shims, just to have them on-hand. Your best bet is to check your clearances (follow the Suzuki manual for the proper procedure, yes, it DOES make a difference), then remove your shims ONE AT A TIME (do not rotate the engine unless there is a shim in every bucket) to see what they are. Compare the shim size with the clearance to see what you need, then contact the GSR Shim Club and arrange to have those sizes sent to you. If you want a convenient way to record all this information, feel free to take advantage of the offer in my signature.

.

[04colyZQ8]

Some prefer the official shim tool, many of us prefer a zip-tie, it's your choice. I have both, but can never get the 'tool' to work properly and have never been shown by someone who knows how to use it properly.

As for a "shim kit", you will go broke if you buy multiples of all available shims, just to have them on-hand. Your best bet is to check your clearances (follow the Suzuki manual for the proper procedure, yes, it DOES make a difference), then remove your shims ONE AT A TIME (do not rotate the engine unless there is a shim in every bucket) to see what they are. Compare the shim size with the clearance to see what you need, then contact the GSR Shim Club and arrange to have those sizes sent to you. If you want a convenient way to record all this information, feel free to take advantage of the offer in my signature.

.

zip tie?? I'm so far off on my milleage! I did the shims 12-13000 kms ago!! I was at 2.65-2.45mm on a few last time;( getting down to the wire, probably need new valve seats or grind the tops of the valves, soon? Smallest is 2.20? I think I'll order 2.35, 2.40, 2.45, 2.50, times 8? That should be what I need? For the next 15-20000, kms then likely got to pull the head