I just bought a new cam for my xr200, which is the same motor as the trx 200x and when i put it all back together, timed right. It ran like a champ forabout 2 hours. I shut it off to let it cool down and it fired really weak. i took it apart and saw that the cam skipped 4 teeth. when i looked at the tensioners and they show no strength on the timing chain. is there a way you can adjust em on this kind of bike. they said its a spring loaded tensioner. thanks

 

are u sure the chain is not streched... i would not ride your bike untell u figure this out i wish i could help more

 

There is only a couple things that can go wrong.

1. The spring tensioner is week or sticking (some years are adjustable)
2. Cam chain is stretched (how old is your current one?)
3. Cam / crank gears are worn
4. or the cam chain guides are bad. (this is usually the weak spot)

What year is your XR? For $40 you can get a new cam chain and guides.