just wondering if any of u have stock yfz that may be jetted wrong or something . my buddys head pipe gets cherry red within a min or 2. i have takin it apart and cleaned twice and still red. this quads all stock . he removed and through away the baffle would that have any thing to do with it .

 

taking off the baffle no that wouldnt have anything to do with it.

if you can take apart the engine and see if there are maybe scratch marks in the piston sleeve or anythign unusual(never know someone could have really messed up at the factory) just look for obvious things if that doesnt work take it to someone who knows what they are doing.

 

the header pipe glowing is normal they do run a lil lean from factory but the cherry red glow is normal for this bike

 

Hey Scumboy, Gills is right, they are a little lean from the factory and removing the baffle will lean it out even more. He will have to go up 3-4 sizes on the main and shim the needle (half clip) or move the clip down one full position. If he wants more power, tell him to remove the airbox lid, change the main to a 170 (if he is not to far above sea level) and raise the needle 1.5 -2 postions, retard the exhaust cam one tooth and put in a 2 deg advance key.
Makes 42rwhp on my Dyno from 36rwhp.
Dynoray

 

dam u guy r quick , i just double checked and the pistons and sleeve r good to go. now that u hooked me up on a few sizes im back in the ball park . thanx

 

Do searches please, there are many posts on this topic.

 

45 pilot, 168 main should take of it.