As said before, only the gearing count, here's a nice calculator: Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator

I don't know if this is a dig at me or just light hearted joke. Nice work either way.

After actually thinking about it properly, only gearing changes will change it not HP increases. I asked a stupid question.

Hey, the world I live in beats its' drummer to a different tune..

Joke.. light hearted.. and also toward the responses - the "circling of the sharks when blood was smelt" - of the evil establishment.. LOL.. JK..

Naw, really, we all lookin to hep when weez can..

But the bike - Dats sum kinda DoPe A$$ bike!!! ( I think that's how you pay a complement now days?)

Another major factor to consider is the type of tire you run in the rear. I have a 330 with stock 14/42 gearing. I swap the rear tire to change up the gearing.

My Pirelli MT43 Trials Tire (4.00-18) has a circumference of 85.38" (stock Dunlop D605 is 85.45"). Bike runs comfortably at 70mph. I also run an IRC GP1 (4.60-18) and a Kenda TM760 (100/100-18). The circumferences of these are 81.63 and 81.29 respectively.

According to the Gearing Calculator mentioned in the post above, replacing the Pirelli with either the IRC or Kenda has the same effect as dropping to a 13T front sprocket. With the IRC I run about 6000rpm at 59mph which is very close to the gearing calculator's results.

He's ****ing with you.... Everyone gets it from someone, but no harm intended, these guys are good ****.... Wealth of knowledge here...

Stop scaring the new guys! 😀

Scary! You Cro-Mags, always "puttin down" us Neanderthals.. Go grow some hair..

LOL!!!! Crazy ****!

Yes, I now know the errors of my thinking. The bike will only move due to the piston moving the crank which then moves gears and chain to the rear wheel.

Thanks for the link it has been helpful. I have fitted the 15 tooth front sprocket and using that link inputted my current rear tyre size and I'm getting the equivalent of a 14/42 with standard sized tyres. Taken it for a ride with that setup and wouldn't want to gear it any taller as it is rather flat and lifeless at 110km/h. I don't think that the 351 kit would make too much difference at that sort of speed so I'll keep this bike until I am confident on the dirt then look at getting a DR650. I have an overnighter ride this weekend, so I'll see how the bike performs then.

I was in the same position as you, trying to decided whether to keep the bike or upgrade to something else with more HP. I decided to invest in the 351 kit and TM36 carb for a few reasons. First I like my klx250, it's light and nimble and so easy to ride off road. Second, didn't want the hassle of selling a perfectly good bike to then pay taxes on the new bIke purchase. Third, the KLX250 is a very cheap bike to insure. The last reason, the bike becomes a beast after and almost double the HP.