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Discussion Starter · #1 ·
Ok. I bought a 1999 gsf 600 on Friday. Problems with the bike then is when you start the bike it would run with full choke but as soon as you let off any choke or use any tiny bit of throttle the bike would cut off immediately. Saturday I took out the carbs cleaned the jets set the floats. Put everything back together cranked it up same issues. Sunday DAY took the carbs out cleaned them a second time. When I went to crank it, it just kept PUTT PUTT PUTT. But would not turn over. I went and got spark plugs thinking the plugs were bad. Spark plug on bank #3 was filled with water. Just where the plug sits not in the cylinder. Figured that spark #3 wasn't getting any spark. So I dried it out best I could put it back together and got it started again but cuts off as soon as you use throttle or let off choke. Sunday night I cleaned the carbs for a 3rd time but this time I decided to set the pilot jet screws. They were all at 2 turns out but out of all the forums I read online I read people are setting theirs to 1 3/8-2 turns out. So I decided to set mine at 1 3/4. OH! and this 3rd time of cleaning the carbs I went and got NEW gas. When I started it this time I am able to let off the choke about 1/2 way and it will idle about 1k but anything less than that it cuts off. Throttle I am able to use now but it wants to bog out when I do so. It isn't a clean rev at all. Any thoughts or suggestions would be great. I purchased this bike for $500 in hopes that it would be a great project bike and could get it on the streets and become a streetfighter member:rock:
 

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sounds like it runs lean as soon as you open the throttle.

check your fuel filter and lines for blockages, better yet, replace them. check to see if your slides are opening together. check the carb diaphrams for tears, along with the intake boots.

does it have any airbox mods? are you cranking it and trying to give it throttle without the stock airbox? (if so, try it again with the airbox and filter in place)

what do you mean plug 3 was filled with water? the cylinder? or just on top of motor around the plug?
 

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Discussion Starter · #4 ·


sounds like it runs lean as soon as you open the throttle.

check your fuel filter and lines for blockages, better yet, replace them. check to see if your slides are opening together. check the carb diaphrams for tears, along with the intake boots.

does it have any airbox mods? are you cranking it and trying to give it throttle without the stock airbox? (if so, try it again with the airbox and filter in place)

what do you mean plug 3 was filled with water? the cylinder? or just on top of motor around the plug?
My bike actually doesn't have a fuel filter, and I will replace the hoses.all the diaphrams and such looked good. Airbos is OEM and I only ever tried to run it with the airbox compeltely asssembeled. Filter is clean too. Water was just on top around the sprak plug not in the cyclinder itself.
 

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Discussion Starter · #5 ·
Classic symptom of plugged pilot jets. Nearly impossible to clean with solvent alone. Best thing is to run a thin piece of wire through them to clean out. Guitar string works great.

I actually did use guitar string all three times to clean them lol. Along with carb cleaner and compressed air to blow them out
 

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With it idling best it can, spray carb cleaner around the intake boots(not into the carbs) If it suddenly revs up or runs smoother, it's got an air leak causing the lean condition, and no amount of cleaning or jetting will resolve the issue until the manifold has a good seal.

If it has a petcock/reserve fuel valve, there's a strainer inside the tank attached to it. Virtually every bike has a filter or strainer somehwere.

If it really doesn't, I would get a generic one at napa or something. One little bit of crud from the tank can plug a pilot in no time.
 

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Discussion Starter · #7 ·
With it idling best it can, spray carb cleaner around the intake boots(not into the carbs) If it suddenly revs up or runs smoother, it's got an air leak causing the lean condition, and no amount of cleaning or jetting will resolve the issue until the manifold has a good seal.

If it has a petcock/reserve fuel valve, there's a strainer inside the tank attached to it. Virtually every bike has a filter or strainer somehwere.

If it really doesn't, I would get a generic one at napa or something. One little bit of crud from the tank can plug a pilot in no time.

I will try the intake manifolds tonight when I get home.

It does have a petcock/reserve valve so then assuming it has the strainer inside like you stated (my first bike sorry still learning everything). Is there a way to check that ? or do I just replace it? (if I can)
 

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I will try the intake manifolds tonight when I get home.

It does have a petcock/reserve valve so then assuming it has the strainer inside like you stated (my first bike sorry still learning everything). Is there a way to check that ? or do I just replace it? (if I can)
It's probably a vacuum-operated petcock, it's a safety feature that shuts off the gas whenever the engine stops (manifold vacuum pulls a diaphragm open to allow fuel flow). If it has a "prime" or "PRI" position, this manually opens that diaphragm to prime the carbs until the engine starts. You can remove it from the tank and rinse off the strainer, but I doubt that's your problem.

You can check that the carb bowls are full by attaching a small length of clear hose to the bowl drain nipple at the bottom. Hold the hose up vertically next to the carb and open the drain screw. The fuel level will show in the hose, it should be not quite to the bowl seam (some carbs have a index mark to indicate correct level).
 

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--Deleted incorrect info--

Something you may want to check is the valve clearances and make sure you don't have tight valves. Another thing may be that you just may need to sync the carbs up.

I'm a carb noob as well, but these are all things I had to do on my Kawi to get it to be able to idle smooth. It had 3 tight valves and one carb whose pilot jet was turned in too much.
 

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My money is still on an air leak if you have definitively ruled out the pilot circuits. The fuel petcock diaphragm is a common culprit. Pull the hose that goes to the back of the fuel valve and suck on it- if you can pull air through it, no good.

There may be nipples covered with rubber caps or screw plugs in the manifolds or extreme front of the carburetors(downstream of the throttle) that serve to sync the carburetors. Rubber caps can leak or screw plugs may not be in tightly. There may be a vacuum line to a charcoal can, or to the fuel tank to recover fuel vapors- check all these hoses for integrity and that they haven't slipped off.
 

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Discussion Starter · #19 ·
My money is still on an air leak if you have definitively ruled out the pilot circuits. The fuel petcock diaphragm is a common culprit. Pull the hose that goes to the back of the fuel valve and suck on it- if you can pull air through it, no good.

There may be nipples covered with rubber caps or screw plugs in the manifolds or extreme front of the carburetors(downstream of the throttle) that serve to sync the carburetors. Rubber caps can leak or screw plugs may not be in tightly. There may be a vacuum line to a charcoal can, or to the fuel tank to recover fuel vapors- check all these hoses for integrity and that they haven't slipped off.
we cleaned the carbs and set the pilot screws to 2 turns out and got the bike to idle with choke fully off. Now it is just throttle. Whenever you use ANY throttle it bogs backfires etc. Not repsonsive at all. And sometimes wants to fly to 4k+ idle after touching throttle.

I will check for air leaks this Saturday when I have time to work on it. thanks for all the help/advice
 
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