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Join Date: Apr 2017
2008 Brute Force 650 Carb Questions
Newbie here... I recently purchased a used 2008 Brute Force 650 (KVF650E) which had been setting for at least a few months and, as expected, the gas went bad and plugged the carbs. The bike has about 300 miles on it. After some initial work (see below) I now have it starting easily and it accelerates well, but the engine won't idle -- it dies without the choke being partially open or with some help from the throttle. The A/F screw seems to have no effect (regardless of where I put it) and the idle adjustment hand screw is all the way in. The diaphragms appear to move smoothly under throttle. I can adjust the throttle cable to prevent the engine from dying, but it's idling way too high at that point.
So far I've:
1)Installed a carb rebuild jet with all new jets, a/f screw (gasket included), gaskets, diaphragm air jets. Main jets are sized at 142 and at 40 for the pilot for both carbs.
2)Cleaned the card multiple times.
3)Drained and refilled the tank with "real" gas.
4)Disassembled the carbs and soaked the bodies in cleaner
5)Checked/adjusted the valves
6)Installed new foam air filter/ (Kawasaki brand.)
7)Replaced the fuel filter -- which I'm now wondering if it's restricting field at low RPMs?
8)Inspected the boots at the top and bottom of the carbs and don't see any signs of cracks.
9)Replaced one diaphragm -- due to me damaging it
I think I still have a carb issue somewhere on the idle circuit, but I'm not finding it. With the carb disassembled, I can blow air through the pilot jet and have air coming from all sides. Ditto for both parts of the main jet. I can blow air through the A/F screw area and feel air on the other side for the carb body, choke uptake (correct name? -- round brass tube in the float bowl). Also, I can blow air from the side port (the small round covered area). The two short, small brass openings at the top allow air to pass downward. I've used a bread-twist wire to open most of these areas. I've sprayed carb cleaner all around the carb manifolds and haven't found any leaks.
I can tell that the previous owner had someone work on it because the main jet was missing from the rear carb, and the main jet for the front carb was setting in the bottom of the bowl -- in short, I'm not sure what all may need to be reviewed.
1) Someone has installed a fuel filter, which I replaced. It's one of those fine screen units. Do these typically present any fuel flow restriction?
2) I noticed that the pilot jet is shorter than the main jet, so is it possible that the float level would be set incorrectly where the main is getting fuel but not the pilot?
3) Any there any other air ways I can check for blockage?
What should I look at next?
Thanks for any help!