GoodDayAll.
2007 KLX250s stock engine with a B.Blue TM33. And a Barker spark arrester. And I'm looking for 100mph. It did that speed ( by the meter ) when it was brand new and just broken in.
I used the " MotoTuneUSA.com method to break it in. Take moment to read the page.

I use that method because SPEED IS THE POINT OF THE WHOLE THING !

Finding my best power with a 147.5 or 150.0 main jet. I can get red line in 4th gear using the 147.5 and red line in 5th gear using the 150.0.
That said...
The rear sprocket is a 42 and the front is a 14.
The only real variable I can see is the fuel. That I can make better / more consistent wth some Boostane. I'll go for say... 95 octane. ( Or as they call it up here in the great white north a 95 anti-knock rating )
Bet I can get red line in 6th w/hot enough gasoline. But I don't want it to crumble under all that compression. ( NO, NO, NO to that ) YES,YES,YES to 100mph/160kph
So I'm thinking I'll go w/the 150.0 main jet. JTSprockets has 39 to 51 tooth rear sprockets available. So maybe the 44 or a 46 tooth. And some real hot fuel...

I ask you, my comrades to think of something I've missed. Or that your experience has taught you. And I missed out on.
ALSO....
What are you running for a main jet and what are your sprockets and top speed?
I want that 100mph back .
BeWell; M

 

the only time i was able to hit 100 was when i was going down a big hill, BUT it was pretty close to bone stock and i changed the sprockets for better highway gearing. i went up to a 15t front and down to a 39t rear (250SF sprocket, 42041-1507). since then i have gone back to a 42t rear but stayed with the 15t front. now i have done all the mods short of a big bore, most recently (last week) i installed a TM36-68 pumper. i was going to get the 33 from B.B but got a 36 instead because there's a little more info on here about it, plus its 2mm bigger than stock. so far from the very little riding ive done with the new carb, there is no doubt i can easily hit 100 if i go back to the 39t. with the 15t front and 42t rear im effortlessly at 90-95 at redline (10.5k). with the stock carb i could only get up to about 80 (tucked down for aero too) or so which put me at around 9k RPM in 6th. if your bike struggles to hit redline in 4th/5th now gearing is not the issue. i think there's something else going on, it could be the jetting is way off or something completely different. its really hard to say over the internet without seeing/hearing/feeling what the bike is actually doing. with the 14/42 gears i dont see how its possible you reached 100 when im maxed at 95 with 15/42. what are your speeds at those RPMs in 4th and 5th? with my TM the bike pulls hard to redline in every gear and i haven't even gotten it jetted to perfection yet. its close but needs improvement and its still 1000 times better than the stock CVK jetted with a DJ144. i assume your TM would be similar, or at least i hope so. its a 33 bored to a 34mm, correct?

 

Hello Scubiedoo22.

Does that TM 36 fit the stock boots?

Yes, it's a TM34. The pull in lower gears is way better than the stock carb.
100mph by the clock. In its first year. So, I had done nothing to it yet. Our pump gas is at best 86. And I usually boost it to about 90 ( Boostane ). 5th gear at/near 10.5k rpm is about 75mph on the clock. That's with the 150.0 main jet. It lacks the power to get to the red line in 6th. That was with regular gas and no boosting. I'm putting the 150.0 back in. the 147.5 has been tested in the different configs. I need to go through the configs with the 150.0 again. Because my memory is waisted. ( See the post on horticulture. )
I've got a 15. ( It might not fit behind my custom case saver. ) So maybe a 39 is the way to go. Instead of a 44.
Still I'll keep working on it.
BeWell; M

 

Here is the link Richard from JTSprockets.com [size=13px]sent to me regarding sprocket ratios.[/size]

See the link below...there is very good coverage in that tooth range.

JT Sprockets: Catalogue

Scroll down.
BeWell; M

 

yes, the TM36-68 was a direct swap. boots and cables fit perfectly, the only thing i needed to "modify" (if you even call it that) was trimming the fuel lines a tad going into the petcock and reroute the throttle cables. did not realize the pump gas up there is that bad, we have 93 at the pump and thats all ive ever used in the bike. that might have something to do with it. exactly what mods have you done to the bike? a list of every single modification including the TM settings when you installed it and what you changed would help since that has a lot to do with the jetting as im sure you know (exhaust, air filter, air box, etc.). when did you install the TM? you might be better off sticking with the stock gearing until the carb is properly jetted to get good AFR readings across the whole RPM range. once the carb is jetted properly you should have enough power to hit redline in all gears, unless the 34mm just isn't big enough. it is the same size as stock so it could just be maxed out on air flow.

a 39 rear would defiantly be better than a 44 if you are looking for top speed.
in general a bigger front sprocket will give you more top end speed at the sacrifice of acceleration, same with a smaller rear sprocket.
a smaller sprocket in the front will have the opposite effect. smaller front will give more acceleration at the expense of top speed, same with a bigger rear sprocket.
changing 1 tooth in the front is roughly equivalent to 3 teeth in the rear.

 

The carb was set by Bill B. We had a lot of trouble in the beginning getting the bike to rev at all. Till I went to , As Bill says the biggest main jet he ever heard used in this carb. A 145.0 I'm now in the 147.5 and 150.0 range. Open the air box. And go between the new Barker and the original w/drill holes. The bike idled very well from day one w/this carb.
I see TM36-68 for sale on Ebay. Between 200.00 and 400.00 USD There are both round and flat slide styles. Take a look and see what u think.
The sprockets I'm familiar with. I just remember my old 10 speed bike. So I know that I don't have the power to just slap in a 39 tooth rear. Hell; I could't get 70mph against the wind in 6th before I started Heavy octane BOOSTING.
The JT Sprocket graphic list of percentage differences when the ratios are applied has me seeing red means less power green means more power; less top speed. But that power should get me to 10K in 6th.
My custom case saver precludes the 15 tooth front. ( I have a 15 tooth. for the 351 kit I also have. But a 44 or 46 rear and a longer chain will I think give me the revs and higher speed only because I can use that last 1500rpm in 6th.
That 36-38 might be a better option. Please look at the adds ob Ebay and let me know which you like.
I was unaware of any other changes to the TM-33 that will allow better high gear performance. If u know of some... I'm always interested.
The sprockets and chain are about 150.. USD And I need tires, 300.00 more.
Now I'm thinking about my testing... I get best performance so far w/the 147.5 main jet and the stock spark arrester. So, I think it is maxed out for air flow
So ... ScubieDoo... " Where are you? " LOL. How much does the TM-36 cost 4 you to buy now?.. And where do I attempt to purchase it?
AnyONE else reading this? In Canada maybe. Hey Got a used TM-36 ????

My 4 legal plants are looking VERY sticky. Any other growers get that "blight" every one else did in my area. Good thing I'm A REAL gardener.
Want to know how I did it? Crowd source me the cash for the TM-36! LOL just kidding Mr. Moderator.

BeWell; M