Gs1100GK hesitation when accelerating

[Rockman]

When I got this bike it ran on about 2 1/2 cylinders. After a bit of stuffing around I worked out that it was corroded connections on the coils. Cleaned these up, put in a new set of plugs and it runs on all four.
Took it for a ride. It will run well at a constant throttle but hesitates and mucks around when I try to accelerate. Still gets up to 160 kmh+ easily enough, but its not right.

So I took the carbies off and cleaned them out. They looked pretty good inside, except for some fine dirt. I cleaned them out and refitted them. Serviced the air filter etc. No change. Still idles well, holds a speed well, but wont accelerate properly. I squirted crc through every hole I could find when I cleaned the carbies.

My first thought is the carbies (diaphragms?), but I did notice that the spark appeared quite weak when I was fiddling around with the coils. My question is then, is the spark normally fairly strong, and my problem is weak spark, or should I chase up a carby kit?

The bike is a 1985 GS1100GK with 32000 km on it.

Thanks, Phil

[Larry D]

Welcome !!
Instead of just spraying out the carbs, this should be done.

http://www.thegsresources.com/gs_carbrebuild.htm

Don't forget to get new o-rings from Robert Barr at cycleorings.com. While you're in there make sure your pilot jets are the correct size. That was the problem with the hesitation in my bike. Put in the proper ones and the bike came alive.

[Steve]

I will second the suggestion to DIP the carbs, not just spray them. Keep in mind that a "dip" is for several hours. Depending on the overall condition of the carbs, you might get away with 4-6 hours, but many of us save the frustration and just do it for a full 24 hours right away. The first set of carbs that I did, I dipped for the maximum recommended time, which is "15-30 minutes". No improvemet, so I got desparate and dipped them for TWO hours. STILL no improvement, so I got REALLY desparate and went for 24. The bike then ran like the proverbial sexually-assaulted primate.

What to use for a "dip"? I don't know what chemicals you have available, but we like to use either Berryman's Carb Cleaner Dip or Gunk (brand) Carb Dip. It comes in a gallon-size can that has about three quarts of liquid (leaves room to immerse the parts) and a basket to hold the parts. When you remove the parts from the dip (do just one carb at a time, please, keep all the parts for one unit together), rinse them according to directions (Berryman's suggests warm water), then use some spray and some compressed air to free up all the passages, then dip the next carb. While you are cleaning, take a single strand of copper wire, poke it through all the holes in all the jets to make sure there is no crud left in them. Copper is softer than the brass jets, so it won't scratch them, possibly altering their fuel flow rate.

No need for "rebuild kits" from eBay or anywhere else. They contain brass pieces of questionable quality, and not nearly enough o-rings to do the job. What you will need is a set of o-rings for your bike from cycleorings.com. The owner of that little site is GSR member Robert Barr. He has kits that have ALL the o-rings for the carbs and the intake boots. When you change the o-rings on the intake boots, there is a good chance you will destroy the screws that hold the boots in place. No problem, he has new stainless Allen-head screws to put in there. Not sure about shipping costs to you, but everything from him will likely cost about the same as one inadequate "kit".

.

[willie]

In addition to the welcome and suggestions of Larry and Steve (especially with regard to the importance of a 24 hr dip) let me strongly recommend installation of a coil relay. I think you'll agree that its the best modification one can do for under $10USD.
Willie

[willie]

While you're in there make sure your pilot jets are the correct size. That was the problem with the hesitation in my bike. Put in the proper ones and the bike came alive.

Hey Larry D. Who did you get the proper pilot jets from?
Willie

[Larry D]

Hey Larry D. Who did you get the proper pilot jets from?
Willie

I got them from a member here who had some extras.

If I were going to get more, I'd probably get them from here.

http://preferredpowersports.com/catalog_keyword_search.asp?searchtype=keyword&keyword=needle+jets&Search=Search+Our+Site%21

[Steve]

Jets are also available from Z1 Enterprises and motorcyclecarbs.com (search for "suzuki pilot")

Not saying they are any better than Preferred Power Sports, just giving you more options.

Another source for some carb parts is Carb Kit Capital, but they don't carry the jets you are asking about.

.

[tkent02]

So I took the carbies off and cleaned them out. They looked pretty good inside, except for some fine dirt. I cleaned them out and refitted them. Serviced the air filter etc. No change. Still idles well, holds a speed well, but wont accelerate properly. I squirted crc through every hole I could find when I cleaned the carbies.

Did you take the needle jets out to clean all of the tiny holes in the jet and clean the bore in the carb body that the needle jet sits in?

Are you talking about full throttle acceleration or just opening the throttle a little bit?

[lucabond]

Do all the pipes get hot when idiling ? Did you set the mixture screws by the highest idle or just an equal # of turns. It will do what you described if the mixture screws arnt set by highest idle. Good luck

[Rockman]

Thanks for your suggestions. I did take the needle jets out and clean them and the holes they fit into. The only thing I didnt take out were the idle jets as these were stuck . Sounds like they will have to come out.
Since I'll probably end up wrecking the jets to get them out , what is the correct size? I havent seen carby cleaner dip around here, but that is probably because I havent been looking for it. If I can get some I'll do a 24 hour dip.

As for coil relays, is there a thread here somewhere on how to do this?

If all this fails, Ill just pull the carbies of the spares bike I have. It looks ugly but does run well.

cheers, Phil

[Steve]

I did take the needle jets out and clean them and the holes they fit into.

Actually, it's not the holes the needles go into that you need to clean. You need to take those tubes out and clean all the little holes in the sides of the tubes.

These are what you are cleaning on the needle jets:



Yes, guys, I polish my jets.

The only thing I didnt take out were the idle jets as these were stuck

When you say "idle jets" are you talking about the "pilot fuel jets" or the "idle mixture adjustment screws"?

These are the "pilot fuel jets" and you need to clean the holes in the sides (if yours have holes, not all of them do) and the hole in the end.

what is the correct size?

Look in the first post at the top of this forum. That is a carb "sticky" that contains most of the stock specifications. Since you have to scroll through several pages to find what you are looking for, it might be easier to go to BassCliff's site. Down the left column you will find a link called Carb Specs: Float Height/Jetting/Cleaning. Click on it (or the one I just gave you) and you will quickly see what should be in there.

As for coil relays, is there a thread here somewhere on how to do this?

There is an often-repeated answer for this: check BassCliff's site. Down the right side this time, you will see a link called Coil Relay Modification.

If you get stuck, holler. Somebody is bound to hear you.

.

[willie]

NICE pics, Steve!

[Rockman]

Aha - I didnt see the brass thingo. I'll pull them apart and have a look. I'm fairly sure the idle jets are ok. It starts almost instantly with a little choke, and idles well. Dont want to touch the idle jets if I dont have to as I will most likely bugger them (and I do mean the idle jets - I didnt touch the mixture screws - maybe I will next time in. Pull them out and clean inside.)

I found the coil relay thread thanks. Amazing thing that search button.

thanks for your help.
cheers, Phil

Actually, it's not the holes the needles go into that you need to clean. You need to take those tubes out and clean all the little holes in the sides of the tubes.

These are what you are cleaning on the needle jets:



Yes, guys, I polish my jets.



When you say "idle jets" are you talking about the "pilot fuel jets" or the "idle mixture adjustment screws"?

These are the "pilot fuel jets" and you need to clean the holes in the sides (if yours have holes, not all of them do) and the hole in the end.








Look in the first post at the top of this forum. That is a carb "sticky" that contains most of the stock specifications. Since you have to scroll through several pages to find what you are looking for, it might be easier to go to BassCliff's site. Down the left column you will find a link called Carb Specs: Float Height/Jetting/Cleaning. Click on it (or the one I just gave you) and you will quickly see what should be in there.




There is an often-repeated answer for this: check BassCliff's site. Down the right side this time, you will see a link called Coil Relay Modification.

If you get stuck, holler. Somebody is bound to hear you.

.