Hey All,

I'm about to pull the trigger on a 351 kit from BB, for my 2009 KLX250sf. Going to follow some of the excellent guides on here. I think I should be ok. I did a big bore on an old 2 -stroke 125 many many yrs ago.

Anyway, needing some advice on the carb. I was just going to go with TM33/34 carb from BB as well as the 351 kit, thinking that I could just do a straight swap between that and the stock carb and be done. Basically in the hope that I wouldn't have to meddle with rejetting, and 'potentially' making a mess of things.

I've never done any kind of rejetting, and truthfully, I'm a little nervous about it. Maybe because I've not done it before? Perhaps it's simplier that what it seems? I seem to have it set in my mind, that i'll never get it right and it'll be a mess of flat spots.. Some things once you start messing, along with a lack of experience and no-one locally I know to help, it could go all wrong.

Anyway, doing a straight swap doesn't seem possible either. Bill replied to saying that with the TM33/34, you need remove the push cable from the throttle AND move the wire bundle from the right side of the frame to the left side.... Yikes.. That seems like it could be a lot of work !!!

So now I'm thinking OK, then perhaps I should re-consider a dynojet rejet on the existing carb, to compliment the 351. It'll be a lot less expensive after all.

My understanding is I need a DJ-2152 kit.

The only other mod i have on my bike at the moment is the FMF Q4 muffler. The header is stock. Bill also recommends the KDX200 snorkle.

So what is the deal between the TM33/34 cable removal, and swapping around of wires.. Is that easier than rejetting? How many of you rejetted without any experience and had success ! How many of you wish you never tried it..

Would it be feasible to take it somewhere with the kit and say, hey how much to fit and tune my carb for me? Or am I making this out to be more difficult that it actually is.

As I said, I'm far more comfortable with installing the 351, than re-jetting. Not cos I know what I'm doing, just cos there's guides that have given me some re-assurance.

I don't think I'll need to drill the starter jet out either, because I live in SW FLorida, which is at sea level for those who don't know. It's always warm, and cold start has never been an issue.. Mind you, I've only had my bike for 6weeks with just over 1000miles. So I could be wrong.

My other noob carb questions is, with a 351 and FMFQ4 and KDX200 snorkle, should I be looking at Stage1 or Stage 2?

Thanks for any tips you guys may throw my way.

 

Not exactly sure on the alteration needed for Bill Blue's carb, but I've not heard anyone say it was complicated at all. If you think that's complicated, perhaps you'd better not venture off into the realm of an off-the-shelf bigger carb. It's all doable, but it will probably be more challenging than BB's carb.

If you stay with the CV carb, I'd get the DJ kit for the KLX300 which is another number I can't recall right now. I think the one you're quoting here is for the '09 and later. Since you're going with a 351 kit, I think the 300 DJ kit and needle will be more suitable.

 

DynoJet #2206 kit for the KLX300 is the one TNC is referring to, I believe.

Don't be afraid of rejetting. Read the rejet threads a few times to gain a little comfort. If you can successfully remove the carb, the rejetting is not too bad at all. Give yourself some time and ask questions here if needed.

 

If you are mechanically minded enough to do the big bore install yourself then I would imagine that the carb jetting would be easy for you. Like IDRIDR said just read through the threads and gather the information you need on the rejet.

The CVK carb is easy to re-jet as you only play with the, pilot jet, main jet and needle + you can cheat and buy a jet kit. With pumper carbs you’ve got to play with air jets, pilot jet, main jet, needles, needle jets, acc pump timing, acc pump nozzles etc so pumpers are a little harder.

I would have through that there is probably someone in Florida with simmilar mods that could give you a ball park estimate on jetting.

 

This is the BB carb, notice the fuel screw.



I moved the wiring over and zip tied to the frame.



Looking down.



You can see the part Bill made to hold the cable. I ran the idle adjuster down by the brake master cyl.



I took the fuel screw that BB sent[T handle with taper like on left] and swapped it for the much cuter one on right. Bad Idea as it ran out of fuel on long up hill [logging roads]. I put the t handle back on and runs fine. That was before I had the 351 kit installed. It runs great with the 351, also have a K&N>



The sticker is the only way you can tell till you twist the throttle.





FMF Q~4 Power bomb, pre 351. I went with all BB because I figured he built the thing. I see some guys using the stock carb and exhaust. It don't have the power my KTM 520 but it is more useable. Just my thoughts, well worth the money.

Go with the stage II[2]

 

If you can do the big bore kit, you can rejet the carb.

Big bore kit has some things you have to be careful of. Cam chain timing is the biggest one. Only one way is the right way.

If you look around here you will find they almost all end up with the same jetting. Some of it is personal preference so you will be close anyhow. The pumper has many more options so it can be tuned more to your riding style. The stock CVK is a little more forgiving. Get the KDX snorkel or remove yours. Bigger cylinder needs to breathe more.

Stage II is what the 351 needs.

I didn't get any Bill Blue sticker on my cylinder. As far as anyone knows its still a 250. You won't believe the difference. Its the best place to put your money.

David

 

Rejet is really easy compared to doing a big bore. The hardest part is just getting the carb in and out.

I used DynoJet kit 2152 with my BB kit. Works great. No need to spend the money on a new carb IMO.

Good luck.

 

FWIW you don't need the pumper carb with the 351. The only advantage, (which is nice ), is a quicker throttle response. I have the 351 and stock CVK carb. Jetting went easy for me, after I gathered a bunch of other jetting set ups from people on here(look in peoples signature lines).
I think the moving the wires that Bill mentions doesn't require any unhooking or cutting, just pulling the bundle to one side, or the other, of where they are now. turnsleft pulled his down, but I think you can also pull them to the left of the carb .
Dan

 

351 with stock carb here and the thing is a Monster and runs like a beast.

 

Wow thanks for all the excellent replies. Wasn't expecting so much useful info. This is a fantastic community forum !!! Learnt a lot from this thread alone.

Sounds like the Bill Blue pumper for me, will be more work that i originally anticipated.

I will go down the rejet route.. Just need to figure out if I should go with a 2152 or the 2206.

The end result I'm looking for is the best rejet for a 351, in Florida at sea level, on a 2009klx250sf bike, with the following mods. 351, KDX200 snorkle and an FMF Q4 end can.

I already have the tail kit and can, which does pop a little on de-acceleration. Do need extra power though. I'll probably order the 351 today. can't wait !!!!