Does anyone know how to lower rpms or raise the top speed on the klx250?

Should i try to change the sprockets?
-I was riding at 9k rpm doing 85mph on the way to San Diego & since it redlines at 11k i had to slow down.

 

You can try going up a tooth on the front sprocket, but it probably won't have enough power to pull it unless you do some engine mods.

 

Yea. Im curious about the same thing. I ride my SF mostly Highway and it Tachs out a lot.

 

There might not be enough room for a larger sprocket up front so you would have to go smaller at the back but again you might never get out of 5th gear (not enough power). The KLX is not intended as a freeway flyer you need a different bike; not a dual sport.

 

What about with Dready's mods?
-carb kit
-exhaust
-intake

Should be enough to change sprockets right?

 

85 indicated is about 76 mph on this bike, due to speedo error on the high end.

You'll need to increase your displacement; 250cc isn't enough for 15T. The KLX300 cylinder and piston will give you enough oomph to drive the higher gearing. A 15T front sprocket will fit. I'm running one right now, but I also have the KLX300 cylinder/Wiseco piston installed.

With this setup, you wont get that much of a higher top speed, but you can cruise at a noticably lower RPM. 250cc isn't enough...I'm repeating this because there has been at least one person who went ahead and tried the 250cc - 15T CS combo and found that you can't hold a decent cruising speed in 6th unless you have zero uphill slope and zero headwind. He did this even though I offered free advice based upon actual experience. Not that it's costly or hard to change the CS then change back, but why go through it all if it's not going to work.

P.S> To get a noticably higher top spend, you need to change the shape of the KLX power delivery curve by dumping lots of money into the top-end and turning it into a high RPM screamer. The bolt-on large bore kits raise the top speed marginally; not anything to worth taking note of. Not sure why anybody would want to do sustained speeds at 80MPH+ on this bike though. It's just not built for that...even in motard form. I have a D-tracker (Japanese version of factory motard KLX) BTW.

 

Nice Explanation! THANKS

 

I have a question, what rpm's are good to cruise @? Mine will cruise 65mph just around 7k. This is actual speed, not speedo speed. Is this hard on the motor to cruise around 7k sometimes going to 7500? What is a safe rpm to cruise extended periods of time?

I think @ 145lbs. I might be able to use the 15t. I will let you know. I have only made it to 70+ (1 or 2 over) very few times. The speedo was around 80. Besides worrying about the rpm's, the knobbies from the original tire start to sway. I need to do some mods this week. Pipe, jet, filter, whale tail delete, and fatty contour bars!