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I have a 1995 KDX 220 and am a weekend rider. First time on the forum and am a novice at working on bikes. I am looking for more top end power and have done a little research. I have gotten a FMF Desert pipe and I had heard that if I bore out my carb and shave the piston head that I will have more power. If so, are there certain specs I should shoot for. Is this true and if so is there someone who is "best in the business" to send it to. If this is a myth is there anything else I can do. Like I said I'm a weekend trail rider and not looking to buy a new bike just for a little more power. Thanks for your help.

Welcome to the forums.

Have you done much with the jetting?

Have you read up on adjusting the timing?

I don't think that shaving the "cylinder head" would be the way to go right now.

Thank you and I'll look into what you said.

Jason wrote:I don't think that shaving the "cylinder head" would be the way to go right now.

I think he is referring to RB's head mod.

OP, jetting will help a bit but the 220 doesn't have a whole lot of top unless you do the mods. You are on the right track. Desert pipe, Ron Black (http://www.rb-designs.com/) carb and head mods, some Boyeson power reeds or better, remove air box lid, and maybe playing with the timing a bit. More involved but the one cure for more top end is to have your cylinder ported for more mid to top end.

The 220 isn't a top end screamer but more of a low to mid range power horse.
However there are a few mods you can do to up the power , the FMF desert or Pro Circuit platinum pipe will help the top end but only if you alter the timing to give more over run which will help these pipes achieve a decent power curve toward the top end. Next I'd go for the 35mm carb off the kdx 200... Keep the 220 needle & pilot jet but install a 152 main & remove only the air box snorkel ... To help with the low end power I would go for the boyesen rad valve & dual stage reeds .... If you want even more power gains then a full port & head job will see a good power increase but you may need to fit a flywheel weight to ease the snap of all the extra HP
I've done all of the above except I run the FMF "woods" pipe & 36mm carb off a kx125 & even with my ported motor I have achieved a smooth yet powerful 40hp on the dyno at the rear wheel.

What have you done to your suspension? Really want to ride faster and fall less, go there first.

Thank you for all the suggestions. Will try them. as for the suspension I have not done anything yet. I weigh 230 pounds. Any suggestions

If the front and rear springs are stock, then you definitely could use some stiffer springs for your weight.

1st thing I would do is determine if you still have the stock piston. Just do a search for 220 piston and read the stories. It's a well documented issue.

if you are only using the kdx as a play bike ( trail riding ) then given your weight I would update the fork springs with XR 400 items with perhaps a heavier grade oil ( simple easy fix )... As for the rear shock I would just give the pre load a couple of turns to stiffen up the shock ... I'm slightly lighter than yourself but not by much & I find my rear shock with a few turns works for me .

What is the 10th digit of the vin number? The 220 didn't come out until 1997. A 220 will have 216L stamped on the lower right side of the cylinder. You may have to peek under the pipe to see it.

John_S wrote:What is the 10th digit of the vin number? The 220 didn't come out until 1997. A 220 will have 216L stamped on the lower right side of the cylinder. You may have to peek under the pipe to see it.

Yeah I was about to mention that as well. I have a 97 220, which is the first model year as you stated.

Check out the Boyesen RAD Valve. It is just a bolt on.

Here is a link that you can take a look at



jtranger_1

Definitely heavier springs in the front.

Sorry its a 2005. Dont know what I was thinking. Lots of great information

If you're just weekend trail riding, dump the OEM piston, then go ride and save your money for good gear, and beer and burgers after. If you have to have more performance, then properly spring the bike, desert pipe/spark arrestor, RB Carb/head mod, and jetting. That will get you into plenty of situations you don't want to be in.