First, hi to you all. I'm new here, I have red a lot since laste week but I just decided to register tonight for one reason. I have a question for you guys, and I was wondering if you could help me.

By the way, as you can see, I'm french and living in Saguenay-Lac-Saint-Jean, Canada, Québec. So sorry for my bad english, and feel very free too correct my writing if ever it would really need. But I'll do my best, I swear. (It would also help me too improve my writing ah ah)


I stop walking around, here's my question. I plan to install some aftermarket stuff on my 09 klx 250 s this winter. But, I was wondering about CFM, I know a bit more car mechanic and I know that part about counting the hp vs cfm of an exauhst is very important. Are you considering that when you're doing your mods?

I was thinking about a setting like this;
Uni air filter
dynojet NEW 250 KAW 09 KLX250S 1 & 2 2152 $64.89
fmf powerbomb header
fmf q4 end exauhst

Would it be a nice setting worth my money? Or the parts won't fit together and I would loose some hp/torque. Or have I to spend my money in an other direction?

I would really appreciate if you could help me, I really don't know much about mechanic as you can easily see. Have a nice evening everyone!

 

That's what i would do, if i were to keep the stock bore.
You MAY have to change the pilot jet also. I too am researching that.

 

But in the dynojet kit, there is no pilot jet? What is the pilot jet doing if i'm not asking too much?

 

Salut et bienvenue sur le site!

You'll find more answers than you got questions here! Best forum I've found and believe me I've searched a lot.

M.

 

Thanks a lot!

 

It's not in the jet kit cause you most likely won't need it so don't stress over it. You'll only know if you need a larger pilot jet once you ride the bike after you do all your mod's.

 

the pilot jet is for mid range circuit.
if you have a rich or lean condition when cruising, you MAY need to change it.
Sometimes a change in the needle position will help but that is just a restriction of the main jet at part throttle.
If you get alot of popping on deceleration with a full exhaust, you are most likely lean in the pilot jet.

 

Don't bother with the Dynojet kit for the 09 KLX250S, get the one for the KLX300R (this one http://www.dynojet.com/pdf/2206.pdf. It gives better performance. Save your money and just buy the slip on Q4 exhaust, the PBomb header isn't really worth the extra cost IMHO if you're staying at 250cc (No big bore.)

Uni filter is a good choice.

Stick with the standard pilot until you've fitted the DJ kit and set it up.

 

Thanks a lot everyone, I really needed your advices.

 

ive got the q4 slip on, no p bomb, in my opinion its the best aftermarket exhaust for the bike. sounds good, not too loud.