Cheap mods??!!

I am after a bit more power for my Rx12. would adjusting the lenght of the stock exhaust have any difference? is it possible to port the stock carb ( like on pocket bikes) or isnt it worth it? I was thinking a new filter, port the stock carb if its not to hard or if its possible, changing the stock exhaust or making a new one, would these mods have any decent performance gains? i got my rx12 to do 55.2mph with alot of carb tuning. what would my top speed be with any mods? would changing the sprocket be a good 'investment'??

Thanks alot for any help!!!

changing your front sprocket to a 16 if yours has a 14 will gain you 3mph or more on the top speed and with a 4 speed tranny you'll prolly not notice the loss on the bottom end. as for the exhaust thats a gamble on 4 strokes. but the x12 has a lot of excessive pipe and bends in the factory pipe so you might see a gain by figuring out a new pipe. maybe relocate the battery box so you can run the pipe over the motor and by chance maybe a nice BBR or FMF xr50 pipe will fit.

thanks for the help but, in a post by steven_d about some immortal problems some people said that changing JUST the rear sprocket will boost topspeed by 17kays???!! i wouldnt mind loosing a bit in acceleration because my 1st gear is a bit to close.

Thanks for the help!!!

Front:
More teeth(Taller) on the front sprocket = More top end, but less acceleration.
Less teeth(shorter) on the front sprocket = Less top end, but more acceleration.

Rear:
More teeth(Taller) on rear sprocket = Less top end, but more acceleration.
Less teeth(shorter) on rear sprocket = More top end, but less acceleration

You can mix and match, I would go with a 14 tooth like what Hot_rod said.

You see where i'm going with this?

-Adam

What teeth are the stock sprockets?

Thanks.

Mike

better edit your post adding teeth to the front has the same effect as removing them from the rear, and vice versa

on most mid bikes the effect of removing 1 tooth from the front is like adding 3 to the rear

on a cag every tooth on the front is like changing 10 on the rear, a

all you have to do is divide the front sprocket into the rear sprocket to get that ratio, that ratio is also your final drive ratio

I am missing what you say is wrong in his post? It looks like he has it right.
And the final drive ratio is taken from the diameter of the rear tire.

what his post says it that adding teeth to the front or rear will make the bike have more MPH, and vise versa

the truth is small on larger on front and smaller in rear = speed

smaller on front or larger on rear = pulling power

final driver raito is the number of teeth on the front sprocket divided by the number of teeth on the rear sprocket

example 6 teeth on the front and 68 teeth on the rear is a 11.33 to 1 gearing

that means the counter shaft (or shaft that holds the front sprocket) will turn 11.33 times for every one turn the tire makes.

tire diameter does effect the final drive, it will not numeraly change the gearing, but adding a taller tire will lower the effective gearing by adding the amount of distance traveled by each rotation of the rear tire. with that said

a taller tire will add speed and lower your torque (or pulling power)

a smaller tire will lower your top speed and make your bike pull harder.

hope this gives you a better understanding of how gearing works

And I do understand gearing. I have been around awhile. I was pointing out that the final ratio is relevant to tire diameter.
He has it right also....he is saying the same thing

Anybody have this info?

Thanks,

Mike

read the part where it says (taller) and (shorter) that is what he has screwed up. trival I know. ;-)how can more teeth on the front or rear make a taller gear?

Yeah gixxer I see now what you meant....he had it right except in that part of his terminology.