This might be one of those 'Doh!' questions, but could someone kindly enlighten me as to how the choke operates on a GS? I've studied my Haynes manual in depth but it's not clear from the exploded view of the carbs what's actually going on. All I can see is a bar going through the intake throat.

I need to know because I'm having some problems now the weather has turned cold. In the morning, the bike starts fine with full choke but when it's warmed up and the choke goes off, it just dies. Eventually it gets warm enough to keep running but ~1000rpm. Riding it to work I get hesitation and surging, and an irregular muffled 'popping' sound from the exhaust. I pulled the spark plugs and the right is fine but the left was sooted right up so it's running rich on one side.

Riding it home again in the evening and it's fine again, so it's not like the mixture screw has fallen out. The bike has ~1600 miles from new and this happened overnight, so I'm suspecting the choke getting stuck 'on', maybe something to do with the cold. Does that sound feasible? I'm too chicken to take anything apart but if the problem persists then I want to take it back to the dealer and say "..... is broken - fix it!". 

The carbs are a mystery without more information. Suzuki calls the choke the "Starter System"




This is from the Suzuki factory service manual. Haynes and Clymer just don't get that detailed.

Just click on the image for the full size version.

In your case with a new bike, I would check the electrical connections for the wiring harness ground (earth) to make sure the ignition controller is not losing what it needs. Your bike also has a Throttle Position Sensor on the carbs to tell the Ignition Controller where the position of the butterfly position is.

I'd take it to the dealer because the warranty should still be in effect with such low mileage (kilometerage??).

So, you're wondering if one of the plungers gets stuck in the "choke on" position in the morning due to cold, but loosens up in the warmth of the afternoon?

I don't know how likely that would be, but it certainly sounds "feasible".  Either way, I agree about letting the dealer handle it while it's under warranty.

Quote from: starwalt on November 18, 2007, 02:20:39 PM
Just click on the image for the full size version.

Wow! Great pic, thanks man. Haynes doesn't even hint at that and I wouldn't have figured it out by myself. 

The bike ran bettter this morning (no hesitation or stalling) but still sounds louder and 'harder' than usual and it feels down on power, especially on standing starts. The left plug is still sooted, and with two knowledgeable posters now suggesting I take it back to the shop then that's what I'll do.

Thanks guys! 

Starwalt, where did you get that factory manual?  I want one.   

Don't tell me "the dealer", it can't be that easy.. 

Hi there,
I ordered my factory Suzuki shop manual for my 1991 GS500E at my dealer years ago.
That's where you get it.
Or order it through one of the discount Suzuki dealers in the magazine ads or online.
Yours,
Todd

I bought one on ebay for 7 bucks. It was sent to me on a CD in pdf form and I had it printed out at school, front and back, for free. Took it to Staples and had it bound for like 3 bucks. Works pretty good for 10 bucks. Lot better than the 65 bucks the dealer told me it was going to cost.

prafeston, can you upload that PDF to this thread?

You know that thing cost me 7 bucks...but I'm a nice guy so I could maybe hook some gstwin members up. It may take a week or so though. I'm on Thanksgiving Break.

If anyone wants the manual pm me your email and I'll just send it to you. I'm pretty sure it is the standard dealer manual.

Forgot to mention that the manuel is 1989-1999.

Quote from: GeeP on November 19, 2007, 06:08:04 AM
Starwalt, where did you get that factory manual?  I want one.   

Don't tell me "the dealer", it can't be that easy.. 

Ok, not "the dealer" but ebay. To tell the truth, I have 3 bona fide copies and one bootleg. Two of the bona fide cover 04 and 05, the other to around 96. The bootleg I haven't looked over much. It came with the second 90 GS I bought.

Suzuki rate from the dealer is around $60 US. Each new version of the manual documents the changes from the "base" unit. I have two types of this manual. Totally bound and hole-punched and the other is loose leaf hole-punched.

I am not certain that the CD version is up to date or even legal - Suzuki does have a copyright notification inside the cover of the printed version.  I don't plan to narc on anyone with one though I will wag a finger...      

Thanks to everyone who posted. The bike got a clean bill of health and has been running just fine...until this morning, when the temperature dipped below 0C last night. The more I think about it, the more I think I'm suffering from carb icing.

There's not much information on how to work around it on the GS500. I found plenty of info for the SV650 but it has carb heaters. Is there a solution for the GS, or should I get my wife's hairdryer playing over the carbs for 10 mins in the morning?

When the roads are icy and covered with salt grit, riding to work on a bike that's snatchy and won't idle just isn't fun. 

A bottle of carb "defroster" (no idea what its called in english) in the tank and the problem should clear in minutes.
Just had the same issue at ~3C

Quote from: TheTazZ on December 13, 2007, 02:35:08 PMA bottle of carb "defroster" (no idea what its called in english) in the tank and the problem should clear in minutes.

I imagine it would be called the same but I've not been able to find it. The only thing I can find is fuel additive/octane booster like Redex. 

By way of update, the bike is running worse and worse as the weather gets colder and is now back in the dealers workshop. The mechanic says it needs new jets and I won't get the bike back until the new year. No big deal - I won't be riding much over Christmas (got the whole week off  ) and the GS is a dog to ride in its current state anyway.

But if the bike gets rejetted for the cold weather, does that mean it'll be out if we have a decent summer? Bikes don't have summer and winter jets do they??

When you say " in english" do you mean British or umerikun? LOL

There is a product called " heat" wally world or any car parts store will have it.
It will take water out of a fuel sys.

It is an alcohol based product. I've used it in cars but not my bike.

BeSafe.

or it might work... take a small blanket and cover the carbs? idk if it will do the job, and if you try it, BE SURE to remove it before starting the bike

QuoteIt is an alcohol based product. I've used it in cars but not my bike.

Thats it lol

No joy with fuel additive, it makes no difference at all. Left spark plug is still sooting up and the bike snatches and surges on any throttle setting. Sometimes the problem magically goes away, especially if the bike has stood for a while, but then returns a little while after I get under way. It's like the wind chill makes it worse! 

I tried new plugs and no change. I've swapped over the ignition coils and no change. Now I'm thinking I'll swap the low-tension connections to the coils - it's wasted spark so I can do that, right? - and if the problem doesn't switch to the right cylinder then it must be the carburettor...

The stealership has given up on it, saying it's carb icing and there's nothing they can do about it. Suzuki GB don't want to get involved. I want to prove where the problem is before I take it back and say "That bit is broken, fix it. Oh, and here's my consultants bill..." 

Quote from: desilva on February 19, 2008, 10:23:28 AMNow I'm thinking I'll swap the low-tension connections to the coils - it's wasted spark so I can do that, right?

Hmmm ... it seems like that would only work if the plugs in both cylinders were normally fired at the same time.  For that to be the case, wouldn't the pistons have to be moving up and down together, with a compression & firing sequence that was either exactly in phase or 360* out-of-phase?

Does anyone know the crank offset between the cylinders?  I wouldn't recommend firing the plugs, say, 90* too soon or too late.