I have odd one here. I have a Yamaha Moto4 I think it is late 80s early 90s. It has issues starting. The engine will turn over fine when I try to start it, but then it slows down like something is dragging. I have tried multiple batteries so I know it is not the battery dieing. So then I tried to pull start it with another 4wheeler. I can get the engine to turn over and run, but as soon as I try to shift to neutral the engine dies. Also when I am in gear and the engine is running it seems I am getting no power to the tires at all. This one just has me so confused.

 

As silly as it sounds check and make sure the emergency break isn't stuck in any way. I had similar problems and tore the 4 wheeler apart to find out that they are notorious for the emergency break to stick.

 

Do you mean the parking bread on the handle bars? If so that is not on. the 4wheeler is easy to push it does not feel like any break in engaged.

 

You may have several problems. Possibly a draggy starter, or poor/dirty connections between the battery, solenoid, and starter....or a corroded ground wire. You may also have a problem with the clutch....improperly adjusted, or possibly worn out.

 

Keep after it. they are great once they're running! I took mine out today.