I have a ty 125 with a ty 175 cylinder and piston (top end) fitted seems to run fine but after about 15-20 mins of trials riding it seems to be getting too hot and then starts to pink.

i got the bike in bits since then its had a full engine rebuild (mains seals rod piston re bore new points condenser ) carb is 125 one tried going up on the main jet a couple of different sizes but no different piolet jet is 25 std so i am going up on that when i get one. Any sugestions all welcome please help thanks

Check you have the correct plug fitted, then check your ignition timing.

You may need to retard it just a little.

What conditions of load, throttle, RPM is the motor under at the time the motor is pinking?

How can you tell it is getting too hot?

Is the bore/rings run in yet?

Is the carby getting enough fuel (blocked fuel tank vent?)

If you have still got the rubber silencer in the airbox lid and the big boxy muffler, the jetting will need to be 1N4 series TY175 rather than 525 series TY175.

I would think the jets are too small. Did you jet up on pilot and main when it was changed?

L

Its running weak and be careful you dont hole a piston, go up on pilot and needle

Dave

Maybe it is the condensor on the ignition.

Chrs:Mike

thanks for replys

running a b7es plug timing seems spot on i can only assume its running lean,going to try another carb i will let all know