GS1000 Pilot screw Help - With Videos

[Guest]

Guys,

https://www.youtube.com/watch?v=KE7gBvnxZMo

I cannot figure out what to set the air and fuel pilot screws to get my bike running back to normal. I probably need a carb sync but have no idea how to do it on the bench.

Any help is much appreciated and will be given credit once I get another video up.

Thanks!!
CafeRob81

[chuck hahn]

The bottom ones ( pilot screws) are usually at 3/4 from the factory..but at 7/8 you should be right. These only effect idle to about 1/8 throttle then your on the needles and the main circuit.

The side ( Mixture screws) are usually around 1 1/2 to 2 to start with pods your tuning problems are gonna be more on what size jets your running..NOT anything to do with the screws. At 3 out on the bottom pilot screws your overloading the circuit and your gonna get nothing but black sooty plugs and if you stand behind it the fumes will be burning your eyes out from being so rich.


With the screws at 3 and 3 in the video your idle circuit is way too rich and at 3 on the mixture screws your way too lean when your on the needles. All that stuttering and popping is because its so lean it can hardly make good combustion and actually make the engine run right.

You set the bottom ones and WALK AWAY AND FORGET THEM!!!!!! ALL tuning is done via the pilot and main jets. The fuel to air mixture is done with the side air ( mixture ) screws.

VM carbs respond expertly when using Colortune to adjust the Mixture screws.

https://www.youtube.com/watch?v=9mKQvWM0nMg&t=273s

[chuck hahn]

Pull the plugs after all your fiddling and see if they are sooted up.. I think they will be.

[chuck hahn]

Carb section starts on page 8-2 here. Read about each circuit and then youll find the vacuum sync procedure further down.

http://zeus.mtsac.edu/~cliff/storage/gs/GS1000.pdf

[chuck hahn]

Jet reference chart.

http://www.jockeyjournal.com/forum/showthread.php?t=64769

[Big T]

so what jets do you have installed?

main should around 120, pilot typically stays at 15, but you might need 17.5

You should probably sync the carbs

[azr]

You should probably start here

http://www.thegsresources.com/_forum/showthread.php?171846-Top-10-Newbie-Mistakes

then go here

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

and while you're at it have a good look around here

http://members.dslextreme.com/users/bikecliff/

[Caferob]

so what jets do you have installed?

main should around 120, pilot typically stays at 15, but you might need 17.5

You should probably sync the carbs

Ill be pulling the carbs later today to re clean and check jet numbers.

[chuck hahn]

GENTLY seat the bottom pilot screws and turn them out 7/8 of a turn. Set them and walk away..like i said they only effect idle to about 1/8 throttle. If all 4 pipes get hot at idle then they are open enough....walk away and forget about them.

Set the side mixture screws at 1 1/2 to 2 and use these to fine tune the fuel to air mixtures for each cylinder...and if you had a colortune you'de see that each cylinders screws setting is gonna be different across the rack. One way to kind of of get the air screws close is to set the RPMs at 1500 and then start turning the mixture screws out on each carb slowly..like 1/8 turn increments at a time and then wait a few seconds so the cylinder rebalances itself....which is LEANING out the mixture. As the mixture leans out youll start to hear the exhaust pop and if you lay your fingers on top of the carbs you'll actually feel the carb shudder as it goes lean and pops.

When it starts acting up you turn the screw IN and start RICHENING the cylinder till it doesnt pop and shudder. Try it on one of the outside carbs when you get it back running and you'll see what i mean.

[Steve]

You should probably sync the carbs

Forget the "probably", you DEFINITELY need to sync the carb first.

Why? You need to ensure that each cylinder is at least breathing. You expressed in your first post that you did not know how to sync carb on the bench. The easiest way is to look through them. Adjust the idle screw so there is just a bare sliver of light coming through the bottom of the slide, compare the size of that sliver of light. Adjust the sync screws so it's as close as you can get.

Now that you know that all the cylinders are at least breathing, you can know that fuel mixture adjustments might work. If you don't sync the carbs, one of them might be closed off, which is the way your video sounds. Your video could also sound that way if one carb was WAY too lean, but you won't have any idea which adjustment to make. If your mixture adjustments don't make any difference in the way the engine runs, then it's obvious that 'mixture' is not your problem. Synching the carbs first will eliminate one variable to narrow down the problem.

.

[chuck hahn]

Or use a paper clip wire bewteen the bottom of the slide and venturi ( from the engine side ). Turn the adjusters till they ( the slides ) contact then wire gently and then ever so slowly relieve the slides till the wire comes out. This will be a very very close bench sync starting point.

[Steve]

Or use a paper clip wire bewteen the bottom of the slide and venturi ( from the engine side ). ...

I have tried that method, but found the "sliver of light" method to be quicker, easier and more consistent. Keeping in mind that the size of the opening is not consistent across the width, you have to be sure to place your paper clip in EXACTLY the same spot in each carb. If you go to either side a millimeter or two, you are setting a different part of the opening to that setting. I find it easier to just look through the carbs than to scrouge around to find a paper clip. I am also a bit hesitant to drag hard metal objects through the carb, risking the possibility of scratching the parts.

.

[chuck hahn]

Im the same way Steve. Ive done so many I know what im supposed to see. But the new guy without a clue needs props. Funny thing i have noticed between Suzuki and Kawasaki manuals is that the Kawi manuals actually have a picture of the paper clip method.

[chuck hahn]

Page 18 in the Kawi 650 manual shows the paper clip method..

https://www.dropbox.com/s/ielbey7s4nwqc96/Z650%20B1%201976%20Kawasaki%20Service%20Manual.pdf

[Caferob]

I cleaned the gs1000 carbs, chem dipped them and cleaned out with guitar string. Bench synced the carbs via GSR forum using a 1/16th drill bit on the 3rd carb then matched the rest.

**Idle to 1/4 is good, 1/4-3/4 sputters and hesitates to climb then full throttle gets full power.

I found out I need to shim the needles and haven't done this on a Mikuni Carb yet. Should be interesting.