As I mentioned before, my parts for the carb work came in this week and I just started on it later this evening and finished up with the transformation a just a little bit ago. I trained in the bmwhd-fu whose discipline demands a #125 jet, N1TC needle, clip on 2nd ring, drill slide hole to 7/64ths, air mixture screw out 2.5 turns, and increased airbox flow by using the KDX200 high flow snorkel. The other items are shared by many which instruct to drill the crank case vent to 3/8" and drill the first baffle of the tail piple 1/2".

Well, I didn't get it done until about 9pm so it was dark and pretty late and I didn't get much time to try things out. However, it fired up fine without any problems. I took a spin around the block a few times and noticed improved throttle response and harder acceleration. This mod certainly lives up to its reputation and allows our docile kitten to experience its feral wild side from which it came. It definitely has found some new attitude.

 

[sm=happybounce.gif][sm=bling.gif]

 

Ain't life on a KLX250S grand after getting those baseline mods done?

I find it simply amazing at how much the bike if bottle up by EPA compliance.

 

[sm=nxsmile.gif] Night and day difference. I put in about 60 miles today, both on and off road and to say the difference is noticable is a drastic understatement. The throttle response is wonderful - a little twist of the wrist and the bike responds immediately, no lag. And before the mods, in situations where I would normally gear down to the next lower gear to get some pick-up, not necessary now. The bike has plenty of pick-up now and can power out of places where it would previously bog. It is so much more fun to ride now. I can't imagine anyone not wanting to do this mod.

Also, I was expecting a drop on MPG, but instead I see my MPG has not diminished. Today I saw 70 MPG. I topped it off before I left, then put in 61 miles, then topped it off again and calculated the milage: 70.3 MPG. I did have a good bit of roads in there, though, typical speeds were 40 to 50 MPH. However, there was a good mix of trails in there also.

I think this may lend some credibility to my theory that the gearing reduction affects MPG more than the carb/airbox/tailpipe mods, especially on the road where you spend a lot of time in the top gear and thus running higher RPMs with the gearing changes to get up to speed.

 

Brian,

Actually the increase in fuel mileage does not surprise me. The engine is running more efficiently now, you don't have to whack the throttle wide open to get something to happen. The power comes on more quickly now, so you get the satisfaction of grunt. As you said, a downsift to a lower (read that higher engine rpm condition) is not needed now, a simple throttle twist takes care of it nicely.

So, more snap, less fuel and more fun.

I'd say that this mod package is something that everyone needs to install.

I'm now waiting for my 13 tooth sprocket to get here so I can fully enjoy the benefits!

 

I agree with the suggestion that everyone needs to do these modifications, they are great. I have been having a problem with mine latley though, only when it is in the warm up process. I have the Dyno Main jet 128, Dyno needle with E-clip in the 1st slot from base, drilled out 1/2" exhaust, and all the other goodies. I think I need to put the E-clip 3 slots down from the base because right now when I 1st start the engine and for the 1st 5 minutes its really unresponsive at 1/4 throttle, it sorta stumbles then it goes on up in RPMs. But this stumbling only happens in the low RPMs. After it warms up the stumbling is gone though. This is indicating that its too lean there right. Because after an engine warms up that means its running richer then when it was cold. So I think I need to raise the needle to get rid of the stumbling at the 1/4 throttle position.

I need to get a 45 rear sprocket and a 110 tooth chain too, that way the gearing will be pretty much right where I want it.

 

Do you have the choke on during this warm up stumble or does it last longer than the choke is needed?

Try moving the clip first. That may fix it. If not, verify the pilot screw setting once more. There shouldn't be any stumble (but you know that) so just keep experimenting until you find the problem. If you don't have any luck with the pilot screw, you may want to pull the pilot jet itself and verify it's not plugged with a bit of dirt.

 

Seems slightly counter-intuitive to me, but it's hard to argue with the results. I think my fuel economy stayed about the same, as opposed to getting better though, but that's a minor detail. Seems that if more power is available, that more fuel would be consumed. I guess it all comes down to how efficiently that fuel is consumed and where the power goes. So you must be right in that it is now being converted more efficiently and transferring that additional power where it counts, because there is an undeniable improvement in performance with no loss in fuel economy.

Which begs the question - isn't a more efficient engine that consumes the same amount of fuel yet provides more power better for the environment than one that is less so? At least, isn't it no worse? And if so, I wonder why Kawi doesn't ship it like this to begin with, assuming it's corked up from the factory for purposes of EPA restrictions and not some other reason?

Yes!

To anyone on the fence w/regard to this mod, take it from someone who was on the fence previously. This mod is a no brainer. Bmwhd supplied me the exact parts list and the procedure has been discussed quite often in this forum. Parts list here:

https://www.kawasakiforums.com/m_33703/tm.htm

Procedure w/photos here:

https://www.kawasakiforums.com/m_17800/tm.htm

(Todd, should the above thread be made sticky? Or maybe a new procedure update added to the "parts list" thread that is already sticky which is more concise - there's a lot of chatter in the "procedure" thread.)

Note that in the above "procedure" thread, Todd later switched to a #125 main jet, so just substitute #122 w/#125 for the latest recommendations. It should also be noted that the values are not an exact science - others are happily running other jet sizes and needle combinations. Since I can barely even spell carburetor, let alone tune one, I decided to stick closely with what was known to work as recommended by the experts (thanks Todd!).

I bought my parts from BikeBandit.com and they arrived in about a week. Just use the "Parts Wizard" on the left of the main page and cut and paste in the Kawasaki part numbers. Also, you can get all the parts you need here + the KDX200 high flow snorkel for less than the price of the KLX300 Stage 2 Dynojet kit which does not include the snorkel. Total cost from Bike Bandit is $59.70 which includes the rather expensive $25.89 KDX200 high flow snorkel. That's quite a savings over the DynoJet. The advantage of the DynoJet is that you get several main jet sizes if you wish to experiment.

 

I thought the same thing. Many years ago, right after getting married to my present wife of 33 years, I bought a 1973 AMC Gremlin X with the 258 cubic inch inline 6 cylinder motor. The car I was driving before the Gremlin was a 1971 'Cuda with a 440 cubic inch 6-pack V-8. Yes, the Gremlin was underpowered, but I was in love and the Gremlin got much better gasoline mileage, almost 18 mpg as opposed to the 'Cuda's 10 mpg.

After we moved to Florida, I was doing a lot of traveling and not being able to pass was getting to me. I ordered some parts from a company that specialized in inline 6 cylinder engines, Clifford Research. I ordered a set of headers, a 260 degree cam, a Mallory Rev-Pol distributor, a 4 barrel intake manifold and some other goodies. I took the engine down with 46,000 miles on it and did an angle mill of the head, fitted them with valves from a 290 AMC V-8, cleaned up the runners, port matched the heads to the intake manifold and exhaust headers and then bolted it all back together. Holy Cow, what a difference. Since I lived close to Gainesville Raceway, I took the car up there and made a few passes with it. It clocked 14.80's at 92 mph. This is with a six-banger and automatic transmission.

When I started driving it around some more I noticed something interesting. I was getting 21 to 22 mpg now, instead of 18 to 19 mpg. Guess it was the fact that the engine was making more power with the same amount of fuel. Kind of like the KLX250.

Of course, the EPA looks at burnt hydrocarbons and other things, not overall fuel efficiency. But what do I know?

 

I only use my choke for about 15-30 seconds and shut off choke when it reaches 4,000 RPMs. Then I just let it warm up for about 2 minutes while I throw on my helmet, gloves, etc... during this stage it does stumble alot in the bottom RPMs, and this is with the choke off. Its real sluggish in the response at 1/4 throttle. But after it warms up for about 4 minutes and I ride it about 10 seconds it dissapears. My bike is gonna be outta commission for a little while though, I have 1,350 miles on the stock dunlops and I will dare not drive another mile, the knobbies are completley worn in the middle of the rear tire, its looks like slicks with ***** on the sides now lol, the front tire is absolutley fine though. So I gotta wait for the 606 tires to be delivered and then I gotta learn how to change them.