I am having some problemswith my Keihin Carburetor and would appreciate any help I can get. The problems are:
1) The bike is difficult to start when the engine is cold. The procedure for starting has been ignition off, full throttle, no choke, kick it over 8-12 times, throttle back to idle, ignition on, and choke on. After 6-8 kicks, it might start. If not, all this is repeated again. Once it does start, it idles well.
After 10 min, the idle is very high and needs to be turned down manually on the idle adjustment. It seems when the engine is cold, it's hard to get gas through this carburetor. I say this because when the engine is ice cold, I can remove the spark plug, shoot some gas into the spark plug hole and quickly put the spark plug back in and do not have to go through the above procedures, and it starts. This indicates to me this bike has a hard time getting fuel to the engine intake when cold, due to this carburetor. I have tried to find a reason why it won't function, but I find nothing.
2) If I'm practicing 1.5-2 ft controlled wheelies, and if I do three or four in a row, the engine feels like it's going to cut out. It seems the engine is getting starved of gas, which makes me feel the float in the carburetor is not conducive to its angle being changed. Since this is an off-road dirtbike, you would think this carburetor is designed to tolerate small wheelies.
A few folks have told me the Keihin carburetor on this bike is not very good and I should switch to a Mikuni VM26. Getting an intake manifold to match up to the Mikuni is difficult because the original carburetor has a flange mount to the intake manifold. The new Mikuni does not have a flange mount. It is circular. Someone suggested using the intake manifold from a Honda CR150 and I ordered it. The intake diameter is 38mm. The diameter of the Mikuni carburetor is 35mm. Has anyone out there done any of these conversions?
Does anyone have a solution to the above problems? You can email me at spuntillo@paragonvideoandstereo.com or call at 608-251-1011. If you do not wish to phone me, I can call you back and save you the money. All help is appreciated.