Motorcycle Repair: 4 wheeler, yamaha kodiak, bench test

Question
Chris,

I hope you know something about 4 wheelers. I have a Yamaha Kodiak that had been running great until it sat for about three weeks. Then we went out to ride and it started popping and bogging down and would barely run. I thought it just had water in the gas so I drained and check it but none to be found. I also cleaned the carb and replaced the plug but no luck. Do you have any ideas of what to try next?

Answer
Hi Bruce.
 Did you check the condition of the plugs when you changed them?  That would give you an indication of the problem that you are having.

If you appear to be running lean, then it could be a blockage of the fuel line, or when you cleaned the carb (if you did anything with the mixture screw), there could be a  problem with the mixture being too lean or something got missed in the ports and is blocking (complete or partial) the fuel flow through the carb.

If it is running rich, then the mixture, after the carb cleaning, could have been too rich or the ignition coil is beginning to fail, that could also account for the problem.

To bench test the coil, you will need the repair manual, which has the testing specs, and a multimeter.

You may also want to check the ignition timing and the valves, to see if they are out of adjustment.  You may also want to check the oil.  Is it due for changing?

Let me know what you find.
Good luck.
FALCON