Hey guys. I spent last 6 days reading through all the posts. Even though there is a ton of great information I still have a couple of questions. I am getting ready to do the bellow mods and would like a sanity check by people who already have done this exact combination of parts/mods.
First of all, I am trying to mod ‘09 KLX250S. A lot of the info I saw was for ‘06. Are things same between '06 and '09?
I will only ride it in the woods/trails in MN, WI and may be a little bit on the road to get to the trails. Here are my questions.

SPROCKETS
My understanding is that it is better to leave a 14T front sprocket and replace the rear. So, if I go with 47T rear from Rockymountainatvmc.com Part# 1022350066. (if there is a better choice, please give reference)
- What do I need to do with the chain? Can I use stock chain and make it longer/shorter?
- Or should I just order 514XK-13 – 13 tooth and the noise and wear is not an issue?

AIRBOX
- If I ONLY replace stock snorkel with the KDX200 high flow unit, do I need to do anything with the carb?

EXHAUST (please note, I am in Central Minnesota. According to my GPS I am at about 900’)
I am only looking to do a slip on. Thinking about getting HMF performance series:
http://hmfracing.com/shop/pipes/kawasaki/klx250-06-10
I saw the following write up for ‘06 model:
http://hmfracing.com/forums/showthread.php?t=1617
125 main jet.
40 pilot.
Shim needle .032
2.0 fuel screw.
- Can I apply all of it to my ‘09?
- Do I have to drill anything and if I don’t is it going to be OK?

If anybody modded your ’09 and willing to share I would love to hear whether parts from the “parts list” work for ’09 without any issues and what slip on / jet / kdx snorkel combination works for my area / elevation.
Thanks again.

 

Welcome to the forum. Congrats on getting the KLX. You'll love it. I can't comment on the sprocket but if you read and follow my signature, it will surely transform your bike into what you're looking for. Even at 900 feet, I'm sure my setup would be perfect.

 

i would say go with the 13 tooth, just because its easy to chnage back and forth pending what your riding then. other than that, looks like your set. i would probably say get a new air filter also.

 

Welcome to the forums, changing to the 13-45 setup will still allow you to keep the stock chain. It will also let you use the chain/mud guard if you want to although most of us have put that on the shelf along with the boat anchor of an exhaust. I'm really not sure on the carb similarities but I'm running the 132 and 40 jets, and the full muzzy, a slip on and a snorkel in your situation might be a good choice. Again welcome and post something in the new members area with an introduction so you won't be missed.

 

From what I've heard the hmf isn't as quiet as the FMF that I have. I run the stock sprockets and do just about 1000 rpm's per 10 mph in 6th gear. So at 60 mph, I'm running at 6000+- RPM's. I don't know what the RPM's are when you change to the 14 tooth sprocket up front. I know it will increase your low end torque, but I guess it depends on the type of riding. Now I'm dong 50% street and 50% trail and the 13 works for me. Has any body got any figures on what their rpm's are with the 14 sprocket compared to mine?

 

14 tooth is about 6000 at 60 indicated (about 54 in reality). i find the 13 tooth raise the revs 300-400 rpm, so 6400 at 60. right now, with a smaller rear tire (110/80), im running about 6800 at 60 with a 13. that would mean one step eather way on the profile would be about equal to a front tooth on the sprocket.

 

I have the HMF on my 09

 

The mods I've listed in my signature have worked great. I used the DJ 2206 kit for the KLX300 which requires drilling the slide (easily done) and where I am the elevation is within a few hun of where you are. The Q4 has a great sound and from what I've heard it's a bit quieter than other slip-on options.

 

Hey guys. Thank you everyone for posting your experiences.
I went ahead and ordered the following:
HMF slip on (6630410-001) -- from bike bandit
KDX200 snorkel (555342-001) ---//---
UNI Multi-Stage Competition Air Filter (7168664-001) ---//---
13T front sprocket (514XK-13) -- from www.sprocketspecialists.com/ -- is on back order for a while, so I ordered similar one from a local Kawasaki dealer
Kouba Fuelscrew (FS-2)-- from www.carlscycle.com
Dynojet kit (2152) -- from www.jcmotors.com/
Of course by the sound of it BikeBandit is going to take their sweet time on shipping my order, so I am sure it will be 2 weeks or more before I see my order. Which is ok, cause most of the trails in MN and WI are closed

Please let me know if there are any tricks or gotchas I should be aware of?

I will be following instructions from the http://hmfracing.com/forums/showthread.php?t=1617 but if there is anything else now would be a good time to speak out

Thanks again, definitely let you know how it all went

PS. I am not big fan of making permanent mods. I think if I understand correctly the reason for drilling the slide is to get a better throttle response. What if I don't do it, and what difference will that make? Or is is absolutely necessary?

 

I believe the DJ kit 2152 you are getting does not require the slide to be drilled. Only the 2206 kit I have. As others have said in previous threads, the kits for the 09-10 come with a different spring which will accomplish the same as drilling. The needle is not the same though.