Hi, I am a newie to this great website! I am trying to help a friend out. The machine in question is a 2005 TRX 500FA Rubicon. When the ATV is placed in gear it lunges forward, "locks-up" and stalls. When placed in reverse it moves backwards until the brake is applied and then stalls. I checked out the angle sensor and it tested ok as per the manual. When I removed the motor ***'y, I noticed the gear (that controls the angle sensor?) wouldn't turn. I got it to turn freely by working the gear forward and backwards, however, I still have the orginal problem and the gear continues to lock-up every time I attempt to run the machine. I don't get any code message. I might add here that this problem appeared right after the piston and timing chain was replaced. Do I have a internal problem here or is something else wrong. Appreicate any help.

 

ok two things wrong here, one angle sensor the other is that someone put the sprag clutch in backwards on the centrifical clutch on the crankshaft.

 

Yes the sprag is backwards..

 

Thanks guys for the info! A few follow-up comments, questions if I may.

** Don't know if this makes any difference but I forgot to mention that when the rear wheels are jacked-up off the ground, I can shift the machine in forward & reverse and the wheels turn as if there was no problem.

** Can the angle sensor be bad even if it tested ok with a ohm/volt meter?

** Are there any special tools needed to get into the clutch assy? Thanks!