I too am new here and need some performance tips.I recently picked up a 1994 KLR 250 with only 690 miles on it.Now I want to give it little more oomf,if you know what I mean.

 

Anybody?

 

I guess I'll just figure it out on my own.

 

Start with opening up the airbox, then either pull the baffle (and some owners bore out the spark arrestor) or put on an aftermarket exhaust. On my '89 I have an extra 3"x3" opening in the top of the airbox and the snorkel is removed from the airbox (coarse filter material covers the holes), baffle is out, cone intact, tin can painted flat black with 3/4"-7/8" hole for exhaust cap (held on by hose clamp painted flat black). The needle was shimmed about 4mm, clipped about 2 - 2 1/4" off of the slide spring, had a 42 pilot jet and 127.5 main jet. I liked how it ran with that setup but my gas mileage took a big hit (from 60 to 45mpg). I think the MPG thing is due in part to the jets, part to a fluctuating idle (too fast most of the time) and more aggressive riding style this spring, but to try and resolve the MPG problem, today I dropped down to a 40 pilot and 125 main--will have to wait a tank or two to see how the MPG are. It still runs good this way but I think I lost a little MPH on the top end, and I didn't get enough of a ride in to check for flat spots on the throttle. I also took the shim on the needle down to about 3mm from 4mm. Oh, and I have a 14 tooth front spocket, which made the bike more fun to ride around town and off road. You lose some top end MPH this way but I think it's worth it, especially since I rarely go on the highway.

I found these mods on some other forums and websites--just search around there's plenty of info out there, and someone else will likely reply here as well. Good luck and enjoy the bike, I really like mine.

Chas

 

Thanks for the info.I had heard that the 127.5 was the way to go.I wasn't sure about the needle shim.I think I'm going to get the FMF Q2 muffler for it.Gotta come up with some "toy cash" first though.I need to throw some of my stuff on Ebay.Does anybody know if the KLX 250 exhaust fits on the KLR?There seems to be more options for that bike.Anyway,I'll get the carb parts ordered,which leads me to my next question.Where to get the 127.5?I've only been able to find 120-130.I guess a 127 or 128 would be close enough though huh?Thanks again!

 

Oh,and let me know how the mileage is affected.I love the 60 MPG but won't mind if it goes down to 50.It'll still be a heck of lot better than my car gets.Also,flat spots.Don't really want any of those.This is going to be fun as I haven't done any work on a bike in many years.Heck,I haven't even owned a bike in almost 20 years.I feel like a kid again..........

 

I'll get back to you on the MPG. Shuld be better because my idle is now staying in the 1400-1600 range instead of mostly around 2100 as it was before taking apart the carb on Sunday--plus the smaller jets on top of that. The 45mpg is getting old--you don't realize how good the 60 is until you have to hit the gas station 2-3 days earlier than when at 60mpg. I thought my MPG were close to 60 after the initial jet change but could never eliminate the fast idle to isolate the MPG problem, so who knows.

I got the first two jets (42pilot, 127.5 main) at a Suzuki dealership, just because it is the closest dealer to my house. I went in asking for a 40-42 pilot and 125-128 main and those were the only two they had for this carb. With these latest jets (40p, 125m) one came from the same Suzuki shop, the other from a Honda/Suzuki dealer not too far from my work--again, all they had on hand near the sizes that I requested. (The Kawasaki dealers here haven't had them in stock when I called, plus they are further away from home and work.) I can already tell that the smaller jets (maybe just the main?) have taken a little off of the performance but not too much, just noticeable. I'll be happy with it as is if the MPGs come back close to 60. Didn't notice any flats spots during today's commute (other than the usual 'short' 4th gear--have you noticed that 4th doesn't have much of a range/spread?).

One other thing, when you trim your slide spring do that by tying the coils together. I didn't see that tip until after I had already clipped my spring and may have got it a little too short. And for the needle shim, I used something I found in my bucket-o-bolts, some kind of cable stop from a mountain bike brake cable I think. It's now ground down to the same thickness as three #4 stainless steel washers. I didn't use the washers because the other thing has a narrower diameter, so I figured it is less likely to hang up on the plastic clip, but it sounds like most people use the washers ($0.17 each at Ace Hardware).

We are in the same boat bike ownership-wise, as I went almost 21 years between bikes (had to get out from under parental control to buy the first one).

Chas

 

Well I opened up my air box and guess what.IT RUNS LIKE CRAP!!!!!I'm guessing I need to rejet so I'll call Kawi tomorrow and see if they have the jets in stock.I'll also get a rebuild kit.Seems lean.Give it gas and it goes puh........then starts to go.I hope Kawai has them in stock or I won't be riding for a while.Don't want to hurt the engine running it lean.It's louder than it used to be too.Should it be?

 

You probably need to open the fuel-air mixture screw (idle screw) a bit to make it run better with the increased airflow. This site has some info and pics:

http://home.earthlink.net/~klr250inf...e/klrpower.htm

 

Well today I went to three different local dealers and not one of them had any jets for my bike.Well I think one of them probably does but I talked to some dumb *** kid with tats covering one arm and those stupid things in his ears that make a hole big enough to put your thumb through.You know the things I'm talking about?I think if I'd talked to a parts guy with a clue in life I'd have what I need right now.I did drill out the cap over the mixture screw and fattened it up a lot,but it didn't help much.Do you think that if I stuff a bunch of foam in the air box it will restrict it enough for me to ride it until I can get the jets I need?I still can't find any pilot jets on line.