I didnt see that post about the rpms staying the same and the machine slowing down, good catch merryman.

Did you by chance do a oil change and not use wet clutch safe oil?

Maybe the clutch needs to be adjusted..

 

Very possible as this area needs a very tite seal. Also the airbox needs a good sea also, many try to go with an after market filter and open up the airbox for more air flow but the carb is jetted lean from the factory so any additional air flow will cause a loss of power!

 

What was the final reason for this issue? I am experiencing the same problem after recently replacing the CDI box. The new box is smaller than the original. Could this be a cause for loss of power / bogging down trying to climb hills?

 

Did you check your valve lash and intake boot? What caused you to install a new cdi? Was this happening with your old cdi?

 

I haven't checked the valve lash, but the intake boot is all good. I had to replace the CDI because a few weeks ago the ATV wouldn't start. After process of elimination, it was the CDI box had gone bad. I didn't seem to have this bogging down issue previously. On a ride yesterday, it would not climb a steep hill. It would make it halfway up and then bog down - the engine remained reved up, but wheels wouldn't spin. I was in 1st gear and even with a running start, it wouldn't make it up the hill.

 

What wheeler you working on?

So engine revs high but tires dont turn?

If thats the case the CDI inst responsible for your "bog".

Did you do a oil change and use non wet clutch safe (JASO certified oil)?

Sounds like clutch slipping due to it being shot or wrong oil used.

 

It's a 2000 Yamaha 250 Bear Tracker. I haven't done an oil change.

 

ok.. how about clutch slipping?

Engine revs tires dont turn is clutch or something in your drive train.

If its not engine bog id suggest you start a new thread where youll get new help vs reviving a 3 year old one.

Good luck

 

Thanks, Ajax. I'm going to change the oil since the guy I bought it from a couple of months ago had just changed the oil before I purchased it. I don't know what type of oil he used. It's possible he may not have used the correct oil.

 

Hi, did you solve the problem? I have exactly the same problem, my bear tracker loses power and can't go up hill