I just recently moded my end cap similar to the end cap mr horsepoer makes. A buddy of mine said that since I opened up the exhaust I will loose back pressure (True) and end up burning a hole in the top of the piston. Ive never heard of this. What do you all think ? D

 

nope you wont burn up anything its just like buying an aftermarket pipe just flows straight through the pipe and out the end

 

I just dynoed mine with out the end cap. It ran a little lean on top but nothing to worry about. If that is the only mod you're going to do, I wouldn't worry about it.

 

Thanks guys the only other mod will be a cdi Box. D

 

If in any doubt just jet a little richer as lean conditions can burn up pistons. (more so on two strokes) More flow of air needs more flow of fuel.

 

Do I have to re- jet? I read a post where you could change the clip inside the carb. If so what do you recommend and how is it done. Thanks, d

 

It may or may not be needed depending on your elavation.. Moving the clip on the needle will only afect the fuel mixture on mid throttle
full throttle is controlled by the main jet. if you take the four screws out that hold the bowl on the bottom of the carb you willl see a brass tube stick out you can fit a screw driver bit inside it to unscrew it, when it comes out you will be able to slide a small round headed brass screw out of it which has a hole in it with the number 165 on it this is your main jet. simply replace it with a 170 to be on the safe side.

moving the clip on the needle == moving the clip down towards the point of the needle will make it richer in the mid to 3/4 throttle range

richer = safer
leaner = not so safe
http://www.4strokes.com/
check out this link you might find some usfull stuff

Also the screws that hold the carb together are a real pain in the a#s get some new ones ready before you do battle with them
some one on this forum should be able to tel you which sizes to get.