OK, so I recently purchased a 2001 Scrambler 500 4x4. I did a search on the subject, but really was hoping to get a clearer picture of where I should start with jetting, and which airbox mods work. I know there are alot of Scrammy 500 experts out there, so your guidance is appreciated! Here's the deal....I just bought the Supertrapp IDS2 full system, and will be installing a Unifilter as soon as I can find one. I like the low engagement speed of the clutch, so will leave that alone (for now). I'm really only looking to pick up 2-4 ponies, so I think my expectations are realistic. Is a Dynojet kit worth the money? I was planning on removing the snorkle from the airbox, but should I be doing more like cutting holes? What minor mods (without getting inside the motor) have yielded results? PS, I went with this pipe after considering my expectations, sound levels, noise factors, and cost. It seems reviews of the pipe have been favorable. Thanks in advance!

 

The scrambler has a CV carb which requires a certain amount of vaccum to operate the slide in the carb properly. If you mod the airbox, you have to do more than just rejet. HPD has an airbox/carb mod kit. It costs about $110. Comes with a new aluminum scoop that you attach to your lib. Flows A LOT more air! Also comes with a new main jet, slide spring, and custom HPD modded needle jet tube. They did the research to make it work right. This will work with aftermarket and stock exhausts. But, if you dont want to go that route, I would first check your plug. If you are running a little lean, then try a 160 main jet and the pilot screw about 1.5-2 turns out. You may be able to get away without rejetting, but let your plug tell you that

 

If your gonna do airbox mods do not get the dynojet kit get the airbox mod kit from Hpd.
But if you plan on leaving the airbox stock the dynojet kit is not a bad value I noticed better throttle response.
I did some mods to my airbox and was running a 160 mainjet and the bike was running good plug was a perfect color bought a dynojet kit put it in noticed nothing because it is not designed for airbox mods. Put the airbox back to normal installed the dynojet again with the 155 mainjet the recommend because of my pipe And this time I did notice a diff and a little better on fuel also.
But if I had to do it all over again I probly would have bought the Hpd airbox mod because they did the research and dyno tested it so there it is
I guess the moral of the story is if the manufacture of the after maket parts dyno's andd does the research on them do not stray from the recommendations they lay down.

So hpd prob a little more power gained from there mod. And dynojet not as much power gained but a little better on fuel then the Hpd mod.

This all being said I am gonna get the HPD mod just waitng for the warmer weather I do not have an indoors location to work on my quad plus winter is my fav time to drive.