I purchased the bike last week, on the ride home I noticed the speedometer wasn't working and there was a occasional hesitation in the lower revs. I drained the tank, cleaned the carb and petcock. Afterwards it ran great. I then changed the speed sensor. After installing the sensor my bike didn't want to start and when it did it was only running on the back cylinder. I pulled the plugs. The front one looked brand new and the rear one had carbon on it. I tried another set of plugs and got the same results. Both cylinders are getting nice blue spark. I tried switching the plug wires around but the bike still only runs on the back cylinder. I also checked the battery voltage I'm getting 12.7v with the bike off and 13.8v with it running. Oh and the sensor didn't fix the speedometer either.

 

I just noticed that when I put the key to the run position without cranking the bike I get one quick spark on both the cylinders. I could be wrong but I don't think it's suppose to do that.

 

I just did a compression test. I'm getting 140psi on both cylinders. I'm really leaning towards it being a ignition problem. I just ordered a new ignition moduel hopefully that will solve my issue. The bike nolonger starts Alll im getting is a occasional 2 foot flame out of the exhaust. I'm thinking that I'm getting spark at the wrong time. I will continue to update this thread until I solve the issue in hopes I can help someone else out.

 

That spark is normal, have you looked at the pick up on the cam? They can get old and "leak" the sealant that is used in the cam sensor itself and become defective. It is the sensor that sends a signal to the ignition module to tell it to spark at the correct time.


It sounds like your having a timing issue, probably electronic related, likely that your cam sensor or ignition module is acting up. But it is odd that it ran fine before the speed sensor change, and now not running right after the change. Can you return the bike to its prior "running fine" state and see how it runs?


Your compression numbers are good. YD

 

I have tried to put the old sensor back in with no change. The bike still won't start. I tried a different ignition controll moduel. It's still not starting. I will look at the sensor.

 

If your getting fuel, then the other components to make an engine run are compression (yours is fine), then a spark at the correct time. You say your getting spark, so this then points spark at the correct time (timing). Are you sure your getting fuel? YD

 

Yesterday I took the bike to a local shop. After about a hour they called me saying they got it running. Apparently they need to replace a seal. I'm going to pickup the bike today. They also were able to determine that my speedometer is bad. I will be going to pickup my bike today and find out what seal they had to replace. I wish I would of brought them the bike from the start $120 out the door and it's running again.

 

Just got my bike home. Ended up being the intake gaskets and a clogged air filter. Now I just need to locate a speedometer.