I'm not slamming HPD in general here, just their airbox mod. I was under the impression that you couldn't remove the airbox lid on the 500 Scrammys without the engine running like crap. But just recently my one riding buddy pulled the lid on his KFX400, which also has a CV Mikuni carb, jetted it WAY up, and viola!! it ran awesome & had alot more throttle response & power. So, it got me thinking, if he can do it why can't I. So I pulled the lid off, jetted it way up and what a difference.

Anyone looking for way more hidden power for a 500 Scrambler, forget blowing $100+ on that airbox mod. 6 turns out on the pilot screw, raise needle 1 notch & a $2.50 170 Main jet and you're set. Now, these are my jetting specs. for roughly sea level, so these settings won't be right for higher altitudes of course. I have a K&N, and outerwares & don't run in deep mud or water.

 

I've tried it before. Although I did not jet up as high as you,I did not have good results. I would not suggest it.

 

Really?? Mine runs great. I guess to each his own, but from my experiences it sure beats a $100 dent in my wallet. And, if people do it on Z400 & KFX400s, that run the same carb, the Scrambler shouldn't be any different.[img]i/expressions/face-icon-small-confused.gif[/img]

 

I think there may be enough variables that in some instances performance may not be negatively impacted. The amount of oiling and type of filter, local humidity, air temp, altitude, distance from the filter inlet to carb, size of carb, etc.. will dictate on which carbs it may work on. For the price of a main jet it would be worth a shot. I know it made my quad sound like it was making more power, but it was not. Quite often louder sound is associated with more power.

 

Oh yes I totally agree that some people think that just because it's louder, it has to be making more power. But for my friends KFX400, after he pulled the lid & re-jetted he could pull 3rd gear wheelies just by nailing the throttle. Where as before, he would have to be in either 2nd or pull generously on the bars in 3rd to wheelie.

Now in the case of my Scrambler, all I know is it runs great & the pipe covers up the intake noise anyway. [img]i/expressions/face-icon-small-smile.gif[/img]