Okay. One step at a time. I read all the forums lately and still have some confusion, even with the nice diagram in one of the forums. And yes, I am a mechanical idiot diving into this but hope to learn something without breaking something!

Here is where I am after spending $400 bucks on my newly purchased used bike that had a serious water pump seal issue (now seems fixed).

Here is what I have so far on the 2009 KLX250S for 50/50 riding of dirt and road:
1) Power Bomb and FMF Power Core
2) KDX200 snorkle
3) Renthal 110mm rise bars (Jummy Buttons)
4) 13 Tooth Front, stock rear sprocket
5) MSR folding mirror
6) STOCK JETTING (dyno jet kit on way... it's on back order)


ISSUES I NEED HELP WITH:


FIRST ISSUE IS JETTING I THINK:
I have the stock jetting so I assume this is the issue. The bike runs like a champ but warms up after 10 seconds of choke as she's ready to go after that. She feels strong from bottom to red line, although when running an extended time at full throttle in 6th gear the bike will turn off and need restarted (either overheating or fuel starvation is my thinking).

The big thing is, on deceleration is pops like someone is shooting a gun at me!!! Confirmed no one was shooting at me, the exhaust pops that loud!!! Popping stops upon pulling in clutch, but with clutch out and no power loud popping again. If I keep just a slight throttle on deceleration, no popping.

I assume too lean. Way too lean. So I ordered Dyno jet Kit. Am I correct on this? Will the DJ kit fix this issue? Fingers crossed I can figure out how to do the jetting myself when the kit arrives.


SECOND ISSUE IS CONFUSED ON FREE MODS:
Okay. I removed one thing so far the seemed to just take up space and serve no purpose. I can not find info on it on this forum.

I removed the black canister on the left side of the bike. It said on it, PURGE TANK. It had 2 hoses that I removed with it. One hose went to the airbox, so I removed that hose too. The other hose went to some other little plastic thing with several hoses leading into and from that plastic thing.

Bike runs fine with it removed, so I assume there is no need for this big black piece of plastic called purge tank or the two hoses I removed with it.

Do I just plug that small airbox hole now or do I have to route that hose I took off somewhere else?

Also, do I just put a little cap on that little black plastic thing with many hoses going to and from it? I assume I just cap the little hole that is left on that thing.


THANKS FOR HELP SO FAR! Once I get this answered, next question will be this. Can I just remove all those hoses from that other black thing that has hoses to the carb and tank and such. Can someone tell me in idiot terms what to do? Do I just pull everything off and cap left over holes? Or is there something I need to route differently?

 

Start by pulling the spark plug and it will tell you if you're running lean or rich.

 

You are definitely running lean. Stock they are lean. Popping on deceleration is a sign of a lean condition. Yes the DJ kit will help. In fact I would not ride it until the DJ kit is installed. Or at the very least pull the brass plug and turn out the fuel mixture screw.

Purge tank? You must have a California model?

 

not sure if cali model. The purge tank thing connected to airbox and to some aparatus that has blue and red labled line coming from gas tank and then those exit to the front of the carb. Seems like i should be able to just eliminate all that stuff but not sure what it is all for.

 

It filters gas vapors out of the tank venting to prevent them from escaping to atmosphere. All cars have it these days, and Cali-spec bikes. It will not affect performance aside from being dead weight.

 

I got it all figured out. I removed everything and capped everything except the blue and red ports on the bottom of the fuel tank. I just routed hose with the other overflow hoses under the bike. I found out mine is a California model so it had all kinds of crap on it others don't have. It's all gone now. I just had to search this forum for 2009 California mods to find what I needed to confirm. Thanks for pointing out I probably had the CA model. Now I just wait for my DynoJet Kit and I'll be set!