I think we should all just meet up and drag race. Haha. That would settle everything.

 

Would have to be a "blind" test though. An impartial skilled rider with no affiliation to anyone in particular running all setups over the same course. Just to eliminate any differences between riders such as weight, skill, riding style etc. That test would be soley the bike's performance. But who wants to stand on the side and watch someone beat on their bike?

 

Okay, here is an exhaust discussion that I feel I could chime in on. From my understanding, the stock KLX250s silencer is almost identical to that of the 300r with the "butt-plug" on it. Unfortunately, your 250s exhaust doesn't have the removable end cap like the 300 does. The most power gained on the 300r, is by ditching the air box lid, replacing the air-filter with a high-flow one (twin-air, etc.), removing the "butt-plug" and rejetting accordingly. These mods alone give a VERY large power increase over stock, and the best part, they are almost free. Now, since the 250s end cap can't be removed, there is a lot of power to be had with a new silencer, BUT, I believe it would be very minimal difference going with an aftermarket unit or a stock 300 piece. The next step for power on a 300 with free mods, or a 250s with free mods and higher flow silencer, would be changing the head pipe and installing the Dynojet kit. The head pipe on both the 250s and 300 is essentially the same, although a have heard that the 250s one is a slightly different length. Anyways, both head pipes have a very cheap design flaw, and the weld on the head flange is on the inside of the pipe, instead of on the outside. Some people have had success with grinding down the weld and rewelding the flange on the outside of the pipe, or, a fourstroke works head pipe could be purchased. There is a noticeable power increase with the aftermarket head pipe and a high flow muffler (300 or aftermarket) than the stock header and a high flow muffler. The dynojet kit makes all of the above listed mods even more effective. I personally believe, with my experience with the 300, and other's experience with older 250r's, that the best bang for the buck would be the free mods listed on planetklx.com, a used klx300r muffler (no butt-plug) from ebay or someone on thumpertalk, a four stroke works head pipe, and a dynojet kit.
It won't sound the meanest or look the best, but there are significant money savings between that option and a full aftermarket system with a DJ kit (maybe $200+).

Oh, and BTW, I have tried a stock klx300 system, stroker head pipe (same as FSW) and stock 300 silencer, stroker and supertrapp muffler, stroker and fmf powercore, and full big gun race. The FMF and Supertrapp had little power gain far up top compared to the stock muffler (but sounded better), and the big gun race seemed to make a little more power everywhere compared to the others. Conclusion: An aftermarket headpipe makes more power everywhere with correct jetting.

Damn that was a lot of typing. I hope this helps somebody.

 

GreenKLX, what SM wheels are you getting?

 

Yea it was basically what you said but from my experiences with the 300's. I do beleive that removing the buttplug and airbox lid, then jetting accordingly adds 5hp. Stroker used to have dyno sheets to show stuff like this, also had one for the crankcase breather mod, it had a 1/2hp increase.


I should update my sig, I have had a set of green excels for quite a while now. I got them while I had my bike apart, so I threw them on my Dad's KLX and had some fun.

My old man's bike with my SM wheels on it.

And here is my KLX that I just recently finished, but I haven't put my SM setup on it yet.

 

Sweeeeeet. I got the black ones off the D-Tracker

 

I ordered my HMF slip-on after alot of thought about all the exhaust systems out there. It was supposed to be in my hands today, but it was delayed at customs, so I will have it tormorrow. Out of all the mods I have done this is certainly the most expensive, but also the most exciting. The slip-on is really going to compliment my snorkel, airbox, air filter, and carb mods.

I will let you guys know my opinion after my first ride with the HMF. I try the quiet core insert as well. See if it changes the performance.

 

Interesting comment on the jetting as opposed to new exhaust. I have just put on the 13 tooth suntour and see some improvement in low end but it will not stand the bike up with a throttle twist. How much gain might I see with just going to a 128 jet?
Thanks,
Pete