Slightly modded '11 Kx450 Vs. Stock/remaped '11 Kx450

Hi there. I have a 2011 Kx450 with the following mods; ported head, hotcams stage 1 exh & intake cams, wiseco high comp piston, precision concepts efi remap & fmf megabomb/ 4.1 rct exhaust & 25/75 vp110/premium pump. My cousin has a 2011 Kx450 w/ MRD full exhaust (which I sold him) and a remap from Kawasaki in mammoth @ the track on premium pump. Gearing on his bike is 13/50 gearing on mine is 13/47. His bike pulls way harder than mine. I feel even with the slightly higher gearing my bike should outpull his given the mods. I have yet to switch out ecu's from both bikes. Any insight on my bikes lack of power compared to a pretty much stock bike of the same year?

That is quite a bit of difference in gearing.

HIs bike pulls harder because of the gear ratio. Since the you both have the same size front sprocket:

The more teeth on the back, the more torque/acceleration the bike will have.

The less teeth, the longer the gears will be.

More hours on your motor?

Gearing wins over minute power mods all day. Wanna beat him in a drag? Add 4 out back, or lose 1 up front. 





I have a 2011 Kx450 with the following mods; ported head, hotcams stage 1 exh & intake cams, wiseco high comp piston, precision concepts efi remap & fmf megabomb/ 4.1 rct exhaust & 25/75 vp110/premium pump

Geez, I thought mine was 'slightly modded' but apparently it's bone stock! 

Thanks for the replies, guys! I know that to get a true test between the two bikes I need to have equal gearing. I figured that with the mods, my machine would just pull the extra gearing with no problem. My bike currently has around 30-35 hrs on the rebuild, my cousins is sitting @ a whopping 110hrs! His maintenence is spot on, though. If he spanks me with equal gearing, I am contemplating running the OEM 2012 KX cams on my next top end. I am wondering if the stage 1 hotcams were a waste of money as I do not want to smooth the power out on this bike in any way. We drag race, drink beer & hill climb in the desert. After buying the bike new and researching things a bit more, I'm wishing I could have found a 2010 Kx450 instead with the more agressive map & cam. Anybody have luck getting a harder hit out of the 2011? Also, is the ratio 1 tooth counter shaft for 3 teeth rear sprocket or 1 tooth counter shaft for 4 teeth rear sprocket?

It's the gearing.big differance.need to try it with equal gearing.I run 13-51

The equivalence varies on the ratio of the bike: at 13:52 is right at 1:4, so 4 teeth rear per -1 tooth front changes are equivalent, at 13:49, is 1:3.78. And so on.

When you guys switch bikes and race, same results?

From the sounds of it it comes down to whoever drank more beer?

He always wins the drags. He is a far better rider than me. What i am talking about is 2nd to 5th gear roll on power. His bike pulls on mine by 3/4-full bike length by the time we are in the mid register of fifth gear. We have never dragged one another on the others bike although we have switched bikes and we both agree his definitely has more oomph. I will be dropping to a 12 countershaft and see where that gets me in the pissing contest. 

Thanks again for the ratio info! I had always thought it was 1 tooth in the front for every three in the rear...

A 12 is going to chew your chain slider like crazy. I would stick with a 13. I run 13/52 on my 07 in the woods and it power wheelies like a liter bike 1st-3rd messing around on asphalt.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now