All i can say is i am SERIOUSLY amazed at how much better the bike pulls on the high rpm range. It cruises and holds freeway speeds easier, and it feels "freed up" I did not think i would notice any change without a rejet but i was deffinately wrong.

Pro's; Shaved quite a bit of weight off the stock exhaust. Gained power on the top end by a very noticeable amount. Looks neat, and cars DEFFINATELY notice you alot more.

Cons, It is pretty loud especially without the spark arrestor plug (which i dont have in
My setup was apparently used for a year or two so i dont know the shape of the packing.
There is a very "FLAT" or soft spot where some tq was lost in the low rpm range lets say 3000-4500rpm...It was annoying at first but i just take off with a little more throttle and clutch a bit more.

Obviously rejetting out of the factory lean is going to help alot.


It also sounds like a true "thumper" at idle and up to 4000rpm now. I love it.

My first performance mod, but if a carb or big bore change the way the bike runs as much if not more...this thing has potential

 

+1

I wringed the neck on my bike in relatively stock (with free mods) form for two years before recently a full exhaust and rejet. What a difference. I can't believe I was looking at trading up not so long ago because I felt the bike was just not living up to my expectations.

I have a 300cc kit waiting to go in, but hooked on riding with my 'new' power at the moment.

 

The slip-on exhaust was by far the single best performance mod I have done to mine. I did it about two weeks before the dynojet kit and uni filter and I was amazed at the difference from stock. The jetting made it even better but not the big difference I saw just from the uncork. I then added the powerbomb and it was another step up.

 

Keep in mind that since you know the bike was lean in stock condition, and you are now flowing way more air, but the same amount of fuel, your bike is bound to be running very lean. My advice is for you to rejet as soon as possible, your bike will thank you for it by starting easier and warming up much quicker, and I think you'll probably take care of that flat spot too. When you do the rejet, you might as well order a new air filter from UNI or Twin-air, and at least pull the snorkle too, to get even more air flowing on the intake side.

 

Actually, im on the fence with the jetting...I can buy the jet kit for 40$ and deal with the PITA carb...and in the future upgrade to the tm36-68 everyone seems to like...frankly i think im going to dump the cash on the pumper carb and start there. No sense in hammering out the stock carb then jump to the pumper that does seem logical.

Also, has anyone upgraded the clutch on the klx? I would not mind one that engages harsher/faster. It feels "soft" compared to lets say a yz250f with a new basket and plates?

 

My experience with these bike and at least one other here with an afr meter was in stock condition these bike aren't lean just strangled, that is why they respond so well to just a slip-on. The instructions with my Powercore 4 said no jetting required but I did it any way and it did run better but I got no real performance increase with the proper jetting.

 

Everybody says every bike is lean from the factory, when in fact, most are not.

I still have the stock carb, and have no intention of changing it. I would work with the stock one for now. It's not that bad a job. Just research what you want to do, and do it all at once, and remove the backfire screen at the same time.

 

my first 5000 miles on my bike were with a two bros slip on and no jet kit. ran awesome with or without the kit. i did notice a little more power with the jet kit and the aifilter being at 500 ft. elevation. i think is why. i could live without the jet kit personally.