DonA,
I'm at a similar elevation around 2800 ft. The #38 pilot screw was too large for me and I couldn't get it to operate properly, especially when riding higher elevation. Went back to the #35 and around 2.7 turns out in town. A kouba screw was installed and I'd drop it back a ways when riding elevation, maybe as far in as about 3/4 turn around 8000 ft.

 

Sweet thanks, Looks like it's goina snow on Monday ...We'll see then

 

Well it did snow , But I didn't get to it , Still waiting for adj thumb screw, Anyway Is there anythjng that can be done to the stock pipe to let it breath a little easier? On The KLR's some guy's drill out the tail pipe and put an after market tip on it ,Until one can afford and after market slip on ..And if there is, Doe's it effect the jetting from the stock instructions? thanks

 

No idea about DIY silencer gutting.. Just get one of the cheaper slipons - DG, Delkevic, etc.. or a slightly used FMF..

DJ instructions still apply - they will always apply unless you decide to go for max power with a lidless airbox + aftermarket exhaust (slipon or full system).. THAT requires a whole different use of the DJ carb kit(s)..

 

That was Fast Thanks ...I guess I'll have to pop for one .The FMF looks good What can do you recommend? I'll have to hold off on the header but if money was not a concern What header pipe do you recommend ? thanks

 

If you go back to the old posts you'll find a lot of folks tried drilling the OEM silencer. It made more noise but performance improvements were questionable at best. And it ruins the spark arrester.

The quietest aftermarket designed for our bikes is the FMF Q4 with quiet core. I found a used one in nice shape on ebay for nearly half of new.

Another option is to find a used KLX300 setup. Look for both the header and silencer.

 

Thanks That sound's like my plan ,Been looking havn't found any used ,either one ,But will keep looking

 

Here is where you start to open a "can of worms".. I own a Q4/Powerbomb system, a PC4/Megabomb system, and a full KLX300R exhaust system.

If you are certain that you will eventually buy a performance header to "augment" a performance slipon, there are things you should know right now.

1. Not all slipons will fit both the stock header and the aftermarket headers (FMF's or the FSW). The performance headers are a larger Dia. than the stock header. Improper mixing of a performance header and slipon is a total waste of time and money - Don't ask how I know(lol). One of my Dyno tests proved this point..

The FMF slipons (Q4 and PC4) correctly fit the stock header and correctly fit the FMF headers (Megabomb and Powerbomb). So, add a FMF header to a Q4 or a PC4 and additional gains in power are "available" - you must change the airbox config and carb setup to take full advantage of the "available" gains.

The FMF header(s) drawback is the lack of, and/or expense of, proper heat shields. Uline carbon fiber shields are about the only "good" shields for the Megabomb. "ARL" found a way to attach the stock shield to the FMF headers though..


2. Only the entire KLX300R system can be used on the KLX250 - you cannot piecemeal the KLX300R system onto the KLX250.. Performance available with the KLX300R system with performance end cap is same-as KLX250 header + slipon.

3. The Four Strokes Works (FSW) header: It will only correctly fit certain slipons - I believe it mates correctly to the FMF slipons..


4. The rule of thumb about slipon mating - If a slipon requires the stock seal in the stock headers' slip joint, it will not mate correctly to any performance header. Such slipons carry the exact same "nipple" size as the stock slipon. DG's, Delkevics, are like this. FMF's and some others will require the removal of the stock seal in the stock header bell - these are the slipons that will fit correctly to a performance header as well.

5. Performance header + matching slipon: Compared to stock header + slipon, this combo "offers" more TRQ higher in the RPM band (6.5k-10.5K) and less in the low/mid range.

6. Stock header + slipon: "Offers" more TRQ below 6.5-7k RPM than #5 and less above.

7. If MCM (Marcelino Cam Mod) is a future mod, it enhances TRQ below 6.5k and offers about the same TRQ above - compared to standard cam timings.

What I have just said saves you hours/days of research in here - but you can verify all with said research..

So, in summary, your choice now needs to be based on what you intend to do in the future. A DG is cheap compared to a FMF. I ran stock header + DGR + MCM + lidless airbox + lidless carb setup - It is a loud, crazy powerful TRQ monster that runs outta breath by 9k RPM. For over a year now, I am running Megabomb + PC4 + MCM + lidless airbox + lidless carb setup. This is power everywhere that pulls to redline. One member running the same has reported top speeds with stock sprockets @ over 100mph (Don't try that at home, he is a professional amateur..)


DGR is loud. DGO is pretty loud. PC4 is my favorite - quiet when driving "normal" , mean "howling" when terrorizing the hoods. Q4 is very quiet everywhere compared to all the others. Most all other slipons are reported to be pretty loud. The Delkevic is loud only once the baffle is removed. The stock KLX300R system with performance endcap is also fairly quiet - comparable to the stock header + Q4.

While adding a "quiet tip" can be done on most all the above, the net effect is to restrict/constrict the exhaust flow which defeats the whole purpose, and the money spent, on improving performance.

 

Klxster seem like a very knowledgeable guy.

I bought a used klx250s last year so I'm still a newbie. It came with a FMF slip on and stock header. I got a FMF clone for Christmas ($88 on ebay). It's a bigger diameter than stock, but I needed to get the connecting end expanded, at a local muffler shop, and cut 4 slits in it for it to fit through FMF. I rode last weekend and did notice some improvement in my throttle response, and possibly a slight increase in torque. I'm happy with it and it seems I was lucky with the setup, not being an expert. I also got the FMF heat shield which fit good.. So far, so good.

 

I have a 07 with the 2206 kit installed. Unfortunately i followed there instructions and drilled the slide hole. I jetted for klx300 with stock exhaust.

I'm at 650 ft elevation and run with a kdx220 intake but lid on (lots of deep water). It runs great on the road, but has a fat response if you crack the throttle on a hot days trail ride. I do ride it to work in the cold down to 10*C. Its fuel range went down considerable after the re-jet.

I'm currently in the 4th notch on the needle, do you recommend the 2nd or third for better performance.
thanks in advance!