KDXRIDER.NET

So I've totally rebuilt my 2003 220, did the RB Head mod and the carb mod. What else can I do to get more power. Ron is totally against an oversized piston, besides I read somewhere they don't make a oversized piston for that motor anymore.

What does "totally rebuilt" mean?

Anything different than stock besides R-B Designs head and carb mods?

Yeah, you really didn't give us a lot of info to tell you "what else"? Also, did you modify the stock 33mm carb or did you upgrade to a 35mm?

New pipe, RAD Valve/Vforce reed set up, air box mod, anti-friction coated piston, high compression piston, and porting are about it. You can also play with the ignition timing and power valve timing to move the power around but you still have the same overall power. You can get in to exotic mods/upgrades but it follows the old axiom of diminishing returns.

Lastly, why do you feel you need more power? If just because you do, that's cool but then the KDX is probably not the right bike for you. A 250cc or bigger bike might be a better option.

Have you put a FMF of Pro Circuit pipe on it? If you go FMF get the rev pipe. I did the mods the Ron recommend for his head/carb update. I got the reeds he recommended and removed the snorkel from the air box then drilled a bunch of holes into the cover. I also run a PC pipe/spark arrester and have no problems keeping up with my buddies on their 250 4t!!

All the power in the world is useless if the suspension is out. Spend some money on getting the suspension right. Best bang for the buck by far.

Sorry I was kind of veg, I do have a Gnarly pipe with the FMF spark arrester. Had the head shaved and carb bored and had the divider plate installed at RB Design and also used the suggested reeds. I leave the top on the air box but cut out that raised section where the snorkel is attached. The bike actually runs great I'm just use to more grunt. When I decided to take on a rebuild I looked all over for a blown 250 but this KDX just kept popping up, talked the guy down to $300 so picked it up and rebuilt the whole bike. I've had a couple KDX bikes through the years and always had fun on them, I just need to adjust my riding technique through certain sections of trail where I'm use to short shifting , I need to be on the pipe more.

Lack of grunt? My 220 (RAD Valve, FMF Desert pipe, RB head and carb, 13/48 gearing) pulls down low better than my buddies Millennium ported, 265cc KX250 with 13/50 gearing.

Something isn't right or you are just use to riding 4T's or 300+cc 2T's. Have you sorted your jetting? Played with your ignition timing? What gearing are you running? Also, I would totally ditch the lid off the air box as, even modified, it restricts air flow quite a bit.

A properly tuned and jetted 220 will not be lacking in low end grunt unless someone has screwed with the porting or you are comparing to 450 4 strokes. I'd go back to jetting and KIPS valve as a start, then check timing.

KDX250, no replacement for displacement.

Jason wrote:KDX250, no replacement for displacement.

That's it, wish I could turn this bike into a 250. The bike has good low end for Cow trailing and I like the close wheel base, I just need to get use to the bike. Actually it's the best running KDX I've had. Guess I was hoping someone would come on and say how they turned theirs into a 250 by using whatever piston from whatever bike. Lots of good info on this site from people that have experimented with these bikes so had to ask. When I got back into riding about 26 years ago in my 30's I bought a KDX and as my son progressed I bought him a KDX So kind of familiar with the bike. Since then I've been through some pretty badass bikes but I guess it's time to slow down. Not even sure if I'll be able to keep the bike, my doctor has me jumping through the hoops. Last few days I've had MRI's and things are not looking good. I might be at the end of my extreme life style.

Hopefully not. Perhaps the KDX will be just enough of a thrill for you.