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Hi all! I'm hoping you guys can help me in Wisconsin. I have a 1999 Classic Touring 500 F/C and just wondering why it seems like it's starving for fuel on the high end? I back off the throttle and she becomes responsive. I did replace the fuel filter. Did a quick inspections of the carbs. ie removed float bowl and make sure wasn't gummed up around the inlet jet, but didn't remove any jets though. Also split apart the fuel pump and cleaned it. looked cleaned. Still didn't matter. All gas lines look OK. I even changed to a brand new belt and plugs. What gives?? As a last resort I drained all the gas. I plan on really cleaning up the carbs and getting into them more thorough and getting a pump rebuild kit and putting new gas in. OR.. am I wasting my time as its a bigger, underlying issue that I'm not aware of. Thanks to any and all that chime in on this thread!!:dunno:
 

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You seem to have covered most of the bases. I would clean the jets, just to rule those out as an issue. Another thing to check would be the carb vent lines and the fuel tank vent lines. A kinked line can create a top-end fuel starvation. Make sure all the vents are clear.

Next time it happens, kill the engine and pull the plugs. Are they dry? What color?
 

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Discussion Starter #3
Thanks BC Dan for the reply. Where would the gas tank vent line be located, if you know? Something visually that stands out? TIA.
 

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Discussion Starter #4
I found a manual on line and it appears the vent line is attached around handle bars somewhere. I'm sure I'll see it.
 

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Welcome!
It will be attached to a fitting on top of the tank.
Also verify your float is set at 'Level'!
A piece of fuel hose on the inlet and blow into it with your mouth.
Raise the float till it shuts off.
That is your float level.
It should stop as it becomes 'Level' with carb body!
 

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Discussion Starter #6
Welcome!
It will be attached to a fitting on top of the tank.
Also verify your float is set at 'Level'!
A piece of fuel hose on the inlet and blow into it with your mouth.
Raise the float till it shuts off.
That is your float level.
It should stop as it becomes 'Level' with carb body!
Thanks KCcats for the heads up. I'll give the shut off check a go. I would think that if the inlet was not shutting off with the floats, it would be getting too much gas and flooding out at idle?
 

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Discussion Starter #8
Well..back to square one guys, but NOW.. it's boggy at low end and takes off like a bat out of hell after a few minutes of bogginess. I cleaned the carbs completely, inspected all jets by removal and checked that floats are parallel when shutting off by blowing into a hose. New gas and crankcase hoses. I cracked fuel pump apart. Cleaned it and it looked OK. Nothing obvious. Gas tank venting checks out. New gas, plugs and fuel filter. WTF?? I'm wondering if its just the fuel pump all along. Thanks to anyone that can give me another solution.
 

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OK try working in and out with the air screws.
Also just for kicks check the center to center on the clutches.
Give them a good cleaning too!
 

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Discussion Starter #10
KC, you gonna have to clue me in on the center to center thing on the clutches. I also move air screw in 1/4 and out the same from the 1 turn out and it didn't really matter. Maybe the clutches are sticking? Also, what do you like to use to clean them? Some sort of spray? TIA!
 

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OK
The center to center is critical because it will change the Ratio of the clutches.
Very seldom is it too far, the belt will squeal.
With the torque of the motor it will PULL the motor closer to the driven.
Remove the driven clutch.
Take a tape measure from the center of the jack shaft to the center of the drive clutch.
I don't know what your dimension is (Cat is 10.2 or 12.2")
You can add shims or washers to the rear mount?

Don't spray anything on the clutches, sand cloth or scotch bright, and blow them out real good!
 

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Discussion Starter #12
I guess i'll have to check that out. I did put a new belt on and it does squeal at times. not sure if that's good or bad. could I just take belt off and see if the engine winds up and the primary moves in an out? Also, had thought that secondary is not coming back in when I slow down and maybe that's why no power on low end? Remember my initial post of bogging on high end. Could be clutches sticking all along??
 

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My 'Cat was doing that along with other symptoms. I finally figured out from research and reading the plugs that it was running lean. I turned the mixture screws in 1/2 a turn and after 2 weeks of riding, it's running perfectly. It seems that many times, we over-analyze things when it turns out to be something simple.
 

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Discussion Starter #14
Factory settings are 1 turn out from seat. If its running rich, then I need to back it out some more? Like a 1/4 turn at a time? Also, what does the c clip on the needle slide actually do? Factory set is said to be 3 notches from the top. When I first pulled them apart, the c clip was set at the second spot from the top and.. the sled did run fine like that at one time. So, maybe just leave it at the second notch. IDK..
 

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For a richer mixture you turn it in, out for lean, which adds more air to the fuel. Mine was missing at high rpm and sometimes backfiring and refusing to accelerate unless I let it idle for a minute, Since I turned the mixture screw in a half turn, it is running perfectly.

As for the needle slide part, someone else will have to answer that.
 

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The cheap easy way that I test fuel pumps is to unhook a fuel line from a carb and crank over the engine with the recoil. 1 or 2 cranks should pump a lot of gas; way more than a Mikuni bowl full. I think your problem is the clutches. The cheap easy way I evaluate clutches is to raise the rear of the sled on a stand and watch the clutches work. The front clutch is closing smoothly as the rear clutch is opening smoothly. If something is terribly wrong it should be obvious from watching it. Eventually you are going to have to invest in a manual and service this stuff yourself because it does need periodic maintenance.
 

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Discussion Starter #18
Its been a bit until I could work on the sled and this is what I found. After all things mentioned above, Clutches are working fin, fuel pump, new plugs. The thing screamed for a while then went back to bogging at low end. It was high end BEFORE I cleaned carbs. Now this. What i did see was a wet and dry plugs after the bog. The one next to the cd box was wet and other one dry and brown. Also noticed that the carb vent line on that side had gas and was bubbling. I think that side the float is sticking?? Is it the float on that side?? Sticking and flooding that side out?? Please help.. This has me againts the ropes but know its something with the carb on that side. I did think it was the CD box. Like when it gets warm and cuts that side. IDK.. Frustrated in wisconsin..
 

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You should not see fuel in the vent line. I am dealing with float troubles that floods my engine with gas but nothing in the vent lines. You may have found your problem. I am going to set my floats a little lower than spec to be sure it is low enough this time (3rd time).
 

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Discussion Starter #20
Thanks Cadillac. I figured it might be something with the floats. Could it be the inlet Needle valve sticking? I did clean that area and it seemed like it worked. Never really had to adjust the metal part that the floats push from factory.
 
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