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I am turning wrenches on a friend of mine's 2005 KDX220 and I have opined that we can "open up" the green monster and get him a wider power band and more power. It is a brand new unit I found for him for $3000.00 so it does not need a rebuild. I am focusing on the reeds, the pipe and the silencer. I have already installed a JD Jetting Kit and resolved hard starting - I am not however, married to staying with the JD kit as I progress through enhancements.

The riding type is technical single track and this is the first motorcycle he has owned - I talked him out of riding 4-wheelers for safety concerns since we do mainly serious hill climbing. This bike will not need to be set up for racing.
he weighs 175 pounds.

With that backdrop, my question is can someone give me a good tried and true set of alteration suggestions for tweaks that are conservative and provide for good radeability with no poor side effects?

I have read and been told pipes make a difference and they make no difference. Same thing with the silencer. I think it is generally agreed that upgrades on reeds make sense. I have been told to can the carburetor and get one off of a KDX200 (larger CFM) before I do anything, then go to a new silencer. The owner has little patience for tweaking trial and error unlike me, so when I spend his money, I really need to hit the mark more for the convenience factor than the spend factor.

Since he wasn't used to a clutch, I installed a RevLoc and he may be moving away from that now that he can ride the bike without drama. Obviously, for the expense of the RevLoc he is not afraid to have me spend his money, he just doesn't want to be inconvenienced with the tweaking "process" so if we can move to tried and known improvements, that is what I am looking for advice to do.

The result I'd like to obtain is more power down low, a wider power band, and more overall torque/hp over the powerband spectrum. Sounds like an unrealistic target, but some say the KDX220 has all of that corked up inside of it. What say you???

Everything you seek is here

Yes, you can get loads more power from that bike. A FMF Rev pipe would be a good start. Silencer is nice for bling, but won't help you go faster so spend that money on something else. boyesen power reeds to replace the stockers, or a v-force reed cage. If you really want to do something with the carb, just send the stock 220 carb to RB along with the head and have them modded out. Specify what sort of gas you'll be running and where you want to focus the power gains.


Want my real 2 cents worth though? Don't bother with power mods yet. If he's never ridden a bike before this one, it is unlikely that that fresh 220 is lacking anything in the power department. Focus on the suspension first, since it's easier to go faster with better suspension. Make sure the suspension is absolutely tits and then decide where/if it needs to be any more powerful.

I say it does need a rebuild... pitch that genade of a stock piston immediately.

juliend wrote:Focus on the suspension first, since it's easier to go faster with better suspension. Make sure the suspension is absolutely tits and then decide where/if it needs to be any more powerful.

That right there.

Indawoods wrote:I say it does need a rebuild... pitch that genade of a stock piston immediately.

Oh yeah! I forgot to mention that bit. Inda's advice is very good. Replace the stock grenade for a Wiseco piston ASAP. An unexpected complete rebuild is never fun...

I'd go with a piston replacement and RBD head for a 220. When the jetting is spot on the motor will be really happy.

Suspension, suspension, suspension. I realize your customer does not want to tweak but you're going to have to get it dialed in. There is a lot to be gained in rider enjoyment by going through the linkage bearings, revalve the shock, oil change and springs up front, carefull sag and fork height adjustments. I'm not just saying that because I read it on the internet. I started with motor first and chassis second and ended up having to put the chassis first and realizing the motor never was an issue.

The result I'd like to obtain is more power down low, a wider power band, and more overall torque/hp over the powerband spectrum. Sounds like an unrealistic target, but some say the KDX220 has all of that corked up inside of it. What say you???

IMO the 220 is already there with just a few very inexpensive changes.

It is a brand new unit I found for him for $3000.00 so it does not need a rebuild.

Yes. It does.

..and doing anything before that is a waste of time, effort and money.

Inda wrote:I say it does need a rebuild... pitch that genade of a stock piston immediately.

That is the correct point of view.

And...

juliend wrote:Oh yeah! I forgot to mention that bit. Inda's advice is very good. Replace the stock grenade for a Wiseco piston ASAP

That's good, too.


You might think you're getting jumped on 'bout a whole lot of nuthin'.

Now...that would be an INcorrect point of view.

They're all doing you a big favor.

In this order:

Wiseco piston, proper lubrication of all suspension bearings, suspension setup/improvements (sounds like he might be OK if he's 175lbs but at least do some site searches on "preload" and get that right), pipe/reeds . . .

if he wants even more power (and probably will eventually) get the Ron Black suite of KDX improvements, he will NOT be disappointed . . .

then maybe start looking at a fork swap.

I think I have a good idea now of my approach. I've heard twice now about the suspension bearings and lubricatioon. Can someone elaborate so I can better understand?

Thanks.

Captn Kirk wrote:I think I have a good idea now of my approach. I've heard twice now about the suspension bearings and lubricatioon. Can someone elaborate so I can better understand?

Thanks.

You need a new piston

How many times you need to hear that?

You must put a new wiseco piston in that bike if you want to do any other work to the bike it all starts and ends at the piston when talking about the 220. The people on this forum know what they are talking about on this piston business and you would be wise to listen. I just had to deal with this same problem and got my piston out just in the nick of time. If your going to do anything good to your friends bike start with a piston, you, your friend and his bike will fair all the better for it.

I just Greased all the linkages and replaced the fork oil, (and ordered fork springs to replace the 130lb rider stock springs) I did all this while not riding it and waiting on my Wiseco Piston to arrive (which I just installed today) The grease was lacking and it needed it! The fork oil was OK but it looked a little thinner that its 5wt replacement. The shock isn't leaking so I didn't do anything to it other than adjust the sag.

(while I had the head and carb off for the top end I sent it to RB who said he as a2-3 day turn around time) so maybe I'll get it back the end of next week!)

1 week down isnt' bad for something that is supposed to be killer reliable and great power when its done!

Captn Kirk wrote:
I think I have a good idea now of my approach. I've heard twice now about the suspension bearings and lubricatioon. Can someone elaborate so I can better understand?

Thanks.

That set of linkages between the bottom of the shock and the frame/swingarm is probably in need of servicing. Sevicing involves dissasembly and re-grease and possibly bearing replacement. The bearing at the bottom of the shock is kind of skimpy and doesn't last long.

More than once I have been unhappy with my suspension performance and spent a month playing with clickers. I've finally given up and sent the shock off to a buddy for an oil change/valving change. While it was gone I thought I would look at the linkage bearings......

Did anyone mention that it might be wise to replace the OEM piston? Something about a cracking issue.......

I'm pretty clear that the piston needs pitching. Along with that I've talked to the owner and he has agreed top do the RB mods to the head, carb and slide.

I ned to find a suspension guy locally who can do the front and rear. Anyone know what I should expect to pay for revalving and respringing? When I did my '04 525EXC it ran about $700 for new springs front/rear, seals and valving. Is that what I should expect for this one as well? Is there a vendor you all know about that knows the KDX well enough to know what to do?

I used a fella on this board. Jason, maybe?
It was a while ago.

The front end is a whole 'nother kettle of fish.

We've come a long way from just opening it up a bit, eh?

Most of these changes and improvements are done incrementally.

Maybe carefully maintained and set up OEM suspension will work for him for now?