Zilla needs a bigger carb??

[ReeperLT500]

I'm thinking that I may need a bigger carb on my 500. The jug is .80 over, ported and polished,reed spacer, pipe, silencer,reeds, and K&N. Here's the kicker, my idle jet is 40(yes 40) and my main is 450. It doesn't load up. I could ride trails all day and won't foul. When I ride hard and slow down it idles kinda high then after a few seconds it goes down to normal. I checked the plug and it's a black/brownish color. It's the stock carb I'm running. What does everyone think? Thanks. -Mark

[racezilla500]

You would definately benefit from going up a size or two. A lot of guys run the Keihin 39mm PWK. Some even run the 40mm. Look at DuncanRacing's website. Their is a good technical support section there and they will also help you if you call them. I called them and they helped me even though I didn't own one part of theirs. Good luck.

[flotek]

id opt for a PWK 39MM ,itll fit right in those stock boots its not much better than stock i thought mine reved quicker with the stocker ,problem is stock have aluminum flat slides and wear out prematurely and cause erratic throttle movement and lean conditions ,alot of co.say the 39pwk is like a +5 hp boost but i say b.s its a nice midrange improvemnet though ,go to hy-tech if you want the best price on your 39mm somewhere like 169$ good luck!!!

[ChuckZilla]

My 87' is doing the same thing. 080 over, FMF, V-Force reeds, 470 main, plug reads on the rich side.
It didn't do it right after the rebuild, but now it's doing it with 20hrs on the motor. I was thinking it's the main seals. Wish I had a leak down kit.