rc_alan

How much fuel do you have through each??? What kind for break procedure did you use??? These motors are just as easy to tune as the old TR's... Check your motors compression, pull the plug out and check it's compression... If it's gone, get a new piston and sleeve set... If compression is ok, and you've checked for air leaks ie... exhaust, fuel tubing, carb leaks ect... If everything is ok, then go back to factory settings on both the high and the low speed needles.. Once the low speed needle is set, leave it alone and just tune the high speed needle... The OS is very easy to tune and holds it's tune very well... Remember, the TZ settings are not like a Sirio or Nova, so if someone tired to tune it like it's a Sirio or Nova, You'll have major problems... Go back to the base factory settings... Put the low speed needle at stock setting as per manuel/OS website and you might have to lean it one or two ticks at the most... Not knowing the temp in your area and the quailty of fuel you're using, it's hard to tune your motor without seeing it... This is just to get you into the ball park... Now, you should be rich still because your high speed needle is at the base/stock setting as well... Just lean the high speed needle one hour/tick at a time to get your settings right while the car is being run on the track and not in the pits... Once the motor is set, you're good to go... If your motor keeps having problems after that... You'll have to take the motor out and take it to your lhs or to someone that can inspect it more closely... As you can see, it's easy to get it right and alot can make it wrong... And without seeing the motor... But this should help get it right... PS... Don't remove any of the shims... Keep everything stock.. Run 20% nitro fuel at least, so go get some new fresh fuel and while you're at it, get some new fresh plugs and fuel tubing as well... Keep that air filter clean too... Goodluck.

RC_Alan