Hello all

I have a 1998 honda 300 trx. I have a web cam 40b cam rockers and springs, wisco 10.25 piston, the head is ported and polished. K@N filter with a cobra exhaust. I have jeted up to 145 main and still run lean to the point of detonation at higher head temperatures. No lean miss. The noise goes away with the choke on which leads me to belive that its still to lean. I run 93 octane, it helps but still have noise hot. My question is has anyone else run this combination and had detonation problems??

Thanks in advance

 

This is the 300EX right? These things run hot when you start messing with the engine. Heat will cause detonation. Only ride it in winter.....

 

Its a 300 trx Fourtrax. Four stoke 2 valve.

 

HAVE YOU TRIED CHANGEING THE NEEDLES OR GO TO DYNO JETS WEB SITE

 

Yes, sorry, I have also install dyno jet kit, thats where I have got the bigger jets from. I have the clip on the richest needle setting. The stock honda jet was a 125, I have increased to 145 and still need more. I have a carb off a blowen 420 ranch. It has a larger bore and may allow me to jet higher for more fuel. I may have to much air flow through the head for the stock carb?

 

yeah you may a 400ex carb will handle it to