Need more top end power

[notenuftoys]

I have a '01 200, with a FMF woods/torque pipe and the airbox lid removed. While the bike will tractor up hills like a 4-stroke, it seems to run out of power at the top end. From about mid-high revs on up, it doesn't make much more power.

I've read through some old posts about Platinum II pipes, which seem to offer some better top end, but are there any suggestions about how to make power through the entire rev range? What about an RB carb port?

PS. I don't want to lose the bottom end power that I have. It comes in handy quite often.

Thanks...

 

[cadjocky]

How about the FMF desert pipe? You'll probably lose bottom end though. I have one on my 1998, but it still doesn't have much top end. The ports must be too small or something on the KDX's.

 

[powerchord1989]

RB carb mod would do exactly what you want more top without losing bottem

 

[Rhodester]

The FMF rev pipe (-30) will indeed make more top end power than the torque (-35) pipe, but you'll have to live with a hit in the power band as well as a little weaker bottom end. That wasn't a good trade off for me. I'm not too sure that the -30 will actually achieve more revs than the -35 will (my opinion based on top speed tests I ran against an XR250 with the two different pipes). Unless I was racing, the -35 produces more than enough top end for my riding style, but I'm not riding on the KIPS all that much.

 

[domino dave]

Boysen power reeds

 

[motoxdude]

im using the fmf fatty gold series pipe and it works great. i still have low end but it gives you more high end and broadens the power band. look into it.

 

[Canadian Dave]

If you are looking for more top end ensure your main jet is properly sized, that your silencer packing is in good condition and your filter is clean. If your plug reading suggest that your jetting is good and you have ruled out any mechanical problems like a damaged KIPS shaft etc then I'd look to reeds, rev pipe and/or cylinder porting. Personally I'd be temped to start with porting if you want to extend top end power. Look to someone with a good deal of KDX experience like Jeff Fredette or Eric Gorr for your cylinder work.

Mechanical Problems - You can easily check the operation of your KIPS system by pulling back the rubber boot on the side of your engine and ensure that the shaft is rotating as your rev the motor. If the top end has been apart the KIPS valves may also be out of time, there is an error in many Kawasaki manuals that wrongly identifies the location of the KIPS sub-port valves. See the JustKDX web site for more details.

A rev pipe will give you more power through the entire rev range over stock. It will have almost as much bottom end as the pipe you have now with more mid and top end. The lack of strong power delivery at higher rpms is to be expected with a torque pipe but from what you are saying I expect there is more going on here than just the profile of a pipe . . . see machanical problems.

The RB carb mod was never intended to increase top end performance but rather improve throttle response and power delivery at lower to mid throttle settings while minimizing the loss of any top end power.

David

 

[Jim Crenca]

I agree about RB carb mod.
My 94 with FMF torque pipe, air box, V Force reeds, etc. did not gain top end with carb mod but did gain a HUGE amount of tractability.
Needless to say flywheel weight didn't change top end power either.
IMO, porting and head work is the key to top end power but I doubt that you will achieve much without a loss at the bottom.

 

[Wolf]

I agree with CD. Assuming your bike is jetted right, and there are no mechanical problems, porting is the way to go...and if you are still looking for more, turn it into a 225 (I've had great success with Eric Gorrs engine work)....still not enough?....go orange;)

 

[notenuftoys]

Thanks!

Thanks for the feedback, guys. And Wolf, don't tempt me to go orange! ;)

When I had my bike apart this weekend, I noticed the filter definitely needs cleaning/replacing. So that's the first order of business. And I'll check out the KIPS system. But the problem seems to feel more like it just runs out of breath as the revs increase to the top end. So a clean/new filter, repacking the silencer, and double-checking the jetting may be the solution.

Then, maybe a rev pipe, cylinder porting, carb mod.... To many mods, not enough $$$. Of course, there's always the orange option (D'oh, did I really say that?!) :laugh:

 

[DirtRoller]

Canadian Dave, has some good points, once you rule out any problems then move onto mods. That being said, building trackable power I would think would be the key(see Jim Crenca post).
I have only done basic mods to this bike and find that the trails that I ride don't require much more top end power. The power delivery is very trackable.
There might be a horsepower to weight ratio that I'm not taking into account. I only weigh 160lbs.
Just think you have 3000 bucks to play with before you should have bought one of these. :joke:
http://www.freeridesouth.com/pics/pictures/3988.jpg