carbs won't rev up unless choke is on.

[toymechanic.]

Yes. If your battery is low, going south, or has a poor ground, ignition voltage can be insufficient at low or even midrange rpm. If coils are out of spec, the same thing will happen. Flat spots in rpm, hesitation, fouled plugs inability to idle, frequently are an electrical deficiency. The weak link in the GS is not the carbs, its the electrical system and operating with 25 year old components and wiring. The order I trouble shoot in is to verify:
1. Battery is in good condition and holding voltage
2. valves are adjusted correctly.
3. compression
4. ignition timing
5. electrical system, coils, plug caps, voltage drop in the system
6. petcock operation and flow
7. charging system, stator output and R/R output.
8. Carb adjustment and synch, induction boot seals and airbox seal and filter.

Until the 1st 6 items are correct, its not possible to properly adjust carbs.
(if item 7 is inoperative, it would not have any bearing until the battery was exhausted to the point of lacking capacity and voltage to support electrical requirements.)

Earl

UPDATE!1/22

I took the K&L 40 pilots jets and drilled out to .020 of an inch verus .0135 where they were, and my dead spot is almost gone. So tomorrow I'm going to drill them out to .o22 of an inch.

compression, schronize, spark plugs,battery, coils, timing, petcock, fuel flow and everything else checked out to be good. It still has a very small hesitation at 2500 RPMs. and I think the .022 will fis that.

I'll keep everyone informed with the progress!

 

[jgordon]

I took the K&L 40 pilots jets and drilled out to .020 of an inch verus .0135 where they were, and my dead spot is almost gone. So tomorrow I'm going to drill them out to .o22 of an inch.

compression, schronize, spark plugs,battery, coils, timing, petcock, fuel flow and everything else checked out to be good. It still has a very small hesitation at 2500 RPMs. and I think the .022 will fis that.

I'll keep everyone informed with the progress![/quote]

Drilling the jets is not as good as the factory jets, In my opinion. Buy the jets and swap them out until you get it running right. If you drill a lillte off center it will not be the same through the bore and will effect you jetting.

 

[toymechanic.]

Drilling the jets is not as good as the factory jets, In my opinion. Buy the jets and swap them out until you get it running right. If you drill a lillte off center it will not be the same through the bore and will effect you jetting.[/quote]

I'm a machinist so I'm not worried. Because the larger drill bit will follow the smaller hole and it would be as centered as the original hole.

But anyway this is all null and void as I have solve the mistery. Who ever had the carbs apart before didn't replace the air pilot jets in the rear of the carbs by the air inlet hoses. Today when I was removing the carbs I notice some threaded holes that were aparently missing something that screwed into them. So I looked at the GS1000GL parts bikes carbs and noticed it had jets in these holes, so I removed one and thought I remember the K&L kits had new ones, but my carbs when I disassembled them didn't have these jets. So I really didn't think any more about it back when I was rebuilding the carbs. I came in the house and looked at the microfiche today and the microfiche showed that the GS1100GL takes number 170 air pilot jets. So I screwed them in, reinstalled the air cleaner and the tank and took the bike for a ride and shusam the problem is fixed no more dead spot. But i did notice that it smells like it is idling rich, so I will take the carbs back off and put the original #40 pilot jets in.

 

[jgordon]

Glad you got it figured out. I use to have some drilled jets laying around but it gets a little confusing when the number on the jet says one thing and the bike is telling you something different

 

[toymechanic.]

Glad you got it figured out. I use to have some drilled jets laying around but it gets a little confusing when the number on the jet says one thing and the bike is telling you something different

Yeah I just engraved the holesize on the jets.

 

[toymechanic.]

After installing the air pilot jets, and put all stock parts back in I still had a bad hesitation again. So now I raised the needles up .125 again and now a very small hesitation. So I guess I will go in and increase the size of pilot jet again!

 

[jgordon]

After installing the air pilot jets, and put all stock parts back in I still had a bad hesitation again. So now I raised the needles up .125 again and now a very small hesitation. So I guess I will go in and increase the size of pilot jet again!

I think you are going to need a 45 pilot.

 

[Guest]

Before I went to pods I ran a K&N in my air filter box without a lid. Ran 47.5 pilot jets, 130 mains and 170 air jets, mikuni jets I should add. About one turn out on the pilot screws and shimmed my needles with two spacers(approx one notch) Bike ran great but a little rich on the main. Probably should of went with 125 mains or 127.5 but it all depends ,as jgordon says, your cam degree. Since then Jgordon degreed my cams and I'm running with a dynojet stage 3. Fifth slot down on needle, 132 dyno main(about 122.5 in mikuni land),170 air jet, 47.5 pilot jets, one turn out on pilot screws and K&N pods.

 

[Guest]

Oh yeah, 4-1 Kerker pipes.