Ok finally got the last video done
KLX250SF mod Part 3 - Cujo Edmonds - Twitvid
It sums up the fast mode of the rejet. I didnt mention some things:
1: If you unknowingly knock out the needle jet and lose it beneath the picnic table and fail to re-install it, the bike runs really lean. I mean the bike 'not-runs' really lean. rookie mistake. Bought a new one and now it actually stays running. and runs well...
1A: the extra Gas from running extremely rich ends up in your crankcase. This now becomes the impetus to change the oil AND filter with some of that synthetic stuff. another rookie mistake...
2: If you move the hose clamps on the intake side of the carb all the way aft to the airbox, you can 'crush' the intake hose to the carb facilitating it's removal.
3: If you put one hand below the carb to push it up while guiding it out the hole with the other, the 'gymnastics' will stay on the TV and not in the shop.
4: You have to drill carefully the pilot jet cover so you do not hit the pilot jet itself when you break thru. I set the pilot to 2 3/4 turns out.
5: pay attention to the hose routing so that you dont burn them on your aftermarket pipe causing another $15.00 US to replace.
6: Rejetting is easy, dont be intimidated, this bike is hard to break.

 

For years I had a buddy who jetted all my stuff, I watched dozens of times as he pulled carbs apart and worked his magic. Finally I tried it on my own, I've been into auto and MC and boat carbs now and it isn't hard but the first one took some courage.

 

I'm thinking this is the pipe I'm gonna go with.

Quick questions for the Powercore 4 informed members here: Will this pipe melt the turn signals ala the Q4? That's kinda why I want this one, don't wanna have to fart around with melting plastic and such.

I would probably order the quiet core insert to go with it so it's not quite as obnoxious. Just wanna make sure this is the right one... FMF Power Core 4, Q4 Quiet Insert w/ Spark Arrestor - Dirt Bike Motocross - Motorcycle Superstore

Also would like to add a thanks to everyone here. The knowledge gained on this sight has saved a lot of worry and headaches.

 

Bump from the depths of page 2 for one more try.

Are you guys subtly telling me to just get a Q4 and stop with the Powercore nonsense?

 

I have the powercore 4. It is just a little shorter and that is why it will NOT melt the blinkers. That is the reason I bought it. It is a tad loud but that doesn't bother me. the Torque increase in the lower to mid range is great.

 

Thanks, cmott. So, you haven't felt the need to go with the quiet core insert? Just freeballin' with Powercore? I can respect that, but I'm not sure how loud it is, as it's hard to tell from youtube.

 

if you want something little louder than the q4....hmf is another good option....i do love the hmf and fmf megabomb combination...whisper quiet at idle...quiet cruising the streets...when you twist the throttle...brap!...

 

I would get the insert, just too lazy and broke to do so.

 

I just picked up a Q4 with insert from a member here. Unused and shiny. Going to replace the loud-a$$ HMF Performance Series can (with quiet core).

The HMF is still in good shape with a few scratches and scuffs. Repacked over winter with only a thousand miles at most since, and at least several hundred of those easy miles with the GF at the helm. If the Q4 goes well, the HMF will go up for sale.

 

I bought an old used PowercoreIV from e-bay. It was supposed to be a klx300 header and pipe, but only the header was from a 300. Decided to put it on anyway. It was LOUD! Loud enough that people were turning their heads to see what was coming down the road and loud enough to give me a headache! I'm planning on repacking it and putting in the quiet insert to see how it is. I need to re-jet when I do that as well.
I will say, despite the noise, there was an obvious increase in low end torque, even with the stock lean jetting. The sound was awesome, just wish it were somewhat more muffled, so I could use it off-road.
If I don't like it, I will try and find a 300 muffler and sell the Powercore. Quiet is key in the NE to maintain trail access and to get into most enduros.
If my klx was street only, I'd pull out the "Loud pipes save lives" attitude and just be a deaf in one ear hooligan.