Here in CA, I like to go an indicated 75mph on the freeways, and with OEM gearing it was revving at 8900 rpm at that speed. Now, with the 15t front sprocket, 75mph has me at 8150 RPM or so. Now, when I put on the 120/80/16 rear instead of the OEM 130/80/16, I should be around 8500 @ 75mph. Overall, so far so good. Took only 30 minutes. Would've been less, but I'm a perfectionist when it comes to chain slack =)

Did notice a slight loss in acceleration, but first gear is also taller, which is a benefit...depending on who you ask.

I have a 15T on mine and I love it. Hwy cruising is so much better. A very cheap and useful mod.

Question! Where do you go to get these sprockets, and what criteria must they meet to fit our bikes. I don't have an owners manual, so I don't know what the specs are. Thanks. :thumbup:

check out sprocketcenter.com

they have front and rear sprockets for ninja 250 1988-2009

i got my 13T front countershaft there (better pulling power from stoplights)

you can get them from Denniskirk.com or motorcycle-superstore.com

Around $15.

Rode again on the freeway and what a joy to use a stupid word. Bike is much qieter cruising at 8200rpm, than 9000. Very pleased with this mod. Acceleration isn't quite as brisk at freeway speeds, but everyone says mpg's are better with the 15t frt and 45 rear. If i notice a benefit, I'll leave it on there, if not, I'll think about taking it off. I use my bike a lot on the freeway and just prefer not to be revving so high all the time. Plus, this engine delops peak torque at 8500rpm, so cruising at an indicated 80(actual 75) puts me right around there with the 15t.