KDXRIDER.NET

Jaguar: Am I missing something? Doesn't this chart indicate significant improvement that would be noticeable?

Don't quote me on anything as I don't know nothing.

I'm still not 100% clear on how the resenator works with the disrupting bit but from what I can tell below 6000 rpm it absorbers some of the initial pressure wave as it leaves the cylinder (takes energy out of it then returning it as the body of the wave passes by and disrupts the flow. There is ignition timing involved in this as well. From this it slowes the pulse trying to act like the pipe is longer. A longer pipe more suited to bottom end. Above 6000 rpm the KIPS closes the resenator off and it's all normal pipe length control.
I suspect the relative small opening to the resenator is probably enough and making the resenator bigger may soak up more and delay the return pulse. So more disruption could equal more bottom end.

While my barrels are off I clean up the lips in the resenator passage in preparation for the day I play.

Please correct my if you think I'm wrong.

I extended my desert pipe by 20mm with an adapter because I did something eles to the pipe to make it act shorter. Made a big difference

Tioll, that does sound like a good explanation.
IDRIDR, what is the difference in the resonator space for those two graphs?

C George wrote:http://bdkraceeng.co.uk/tc/products.php?226

Jaguar: chart found here.

1 inch of increased header length lowers the powerband only 100 RPM

That's an interesting statement. When I raced karts we used headers/pipes designed to use a straight piece of pipe as the coupler. Pipe mfg would specify starting length of header from piston. 1/8" difference in this coupler would move the power up/down about 200rpm. Short=heat also.

that 100 RPM is just a generic number, from one open class motocross bike. Karts are very different in that their rev range is so long, in that they can go to 16,000. So at that high an rpm a short distance change makes a bigger than normal powerband change.
Concerning that graph showing a 9% power improvement, consider that it is from a place promoting those spacers, so they have reason to fudge the truth.

I'm sure it's very similar to the FRP torque ring , on some bikes , some people feel like it makes a difference.

FRP wouldn't have marketed it if it was total snake oil.

Another personal preference in engine tuning.

Try it and see if YOU like it. : )

I'm not selling em , I just enjoy tinkering.

C George,
Thank you for bringing this topic up. I learned some things and may give this one a try.
I find it interesting how some folks appear quite close-minded and yet know everything.

and some people are so foolish as to believe everything they read.
When there's money involved you have to be healthily skeptical.

Lets not end this with an argument as we're all entitled to our opinion.

Bottom line is some engineer far smarter than all of us felt the resonator had a purpose
to make the KIPS system work at it's best. All we're doing is tweeking his design slightly.

Enjoy The Holiday Weekend : )

Yes, I have come up with a theory on all this and the core is that dip in the graph. I have felt that dip and nearly tuned it out more incidentally than by design.

Depending on which exhaust you have will depend on your power curve. The ignition is supposed to flip at 6000 rpm into a more retarded mode. This may or may not be exactly 6000 if there are natural variations in the elotronics. I don't think playing with the advance / retard on the stater plate will change the 6000 value? The Power valves are supposed to open at 6000 ish which would be a even more variable as its govened by a balls, springs and washers then the resenator is a set size so will have a set sweet spot. Put all the variations togeather and that dip could be more or less depending on the natural variables. Fertil ground for tinkerers.

So my approach will be electrics unchangable for the flip but changeable for the amount.

Powervalves opening timing probably best left as a minor fine adjustment and more with shimming than complete washer changing. I'm still suspious that letting them open earlier is a trade off for smoothness over power.

The resonator is the starting point and finding the sweet spot then the ability to move it up or down as required is a start. My approach will be two spacers one twice as large as the one sold. And one the same size. First test is with both togeather to supposedly shoot way over the mark then smallest then mid. From that I should get a feeling for the effect. The rest will follow from that.

I must say though that tuning by the seat of the pants is very difficult with a trail bike the terrain is so variable and what is wheel spin going to tell you. Then if you go fast enough to get out of the wheel spin range its to fast. Ibottom ends not so bad and that RB carb. t takes me a hole day to get a feeling of direction. On a road track it relative easy as its more a formulated approach to riding your home track. Them I so out of it now this is only a toy for tinkering, it's what I enjoy.

After riding this bike and using a butt dyno , all I can say is , I don't believe it Hurt the power any . : ) I'm leaving it on.


The power valve opening earlier for smoothness is deffinetly a plus where we ride. The bikes are still plenty stong and you have
no sudden burst of power you don't need. Maybe a 200 rider would think different but a 220 has plenty to over come it.

And that's all you can ask for