My family has a pair of '87 honda 250x's.One has a cobra exhaust,13 teeth on countershaft and 36 teeth on rear.The other is completely stock except it is bored .10 over.My question is does boring that little equal a pipe and gearing,because they still run side by side?What else could we do to get the piped one to run faster?Within reason, we don't want to spend a fortune on a almost clasic machine.
thanks for you time and advice.
Shannon

 

Put a 14T front sproket on both of them and see how much better they run. The sproket should cost less than $15. The Corba exhausts are not very good exhausts, much noise and not much of a gain. I would guess that that exhaust is about equal to the 1st overbore that you have.

 

cobra pipes dont do anything boring it out wont do anything by a supertrapp pipe or just regear it again

 

boring it out wont do anything but increace displacment. it gives that one more cc

 

When was the last time the valves were adjusted? Dirty air filter?