2006 klx250s

Picked up this 06 last summer for $2500 all stock with 4000k miles on it . Since then i have put an HMF pipe, K&N filter and jetted it .

I have a few questions reguarding gearing and chain length. Currently been running a 13/42 set up for trails and a 15/42 when i ride the road and the 106 link chain has worked good .
I want to run a 15/39 for road but i need to figure out chain length. I have found on here once that someone was running a 104 link chain with this set up. Can anyone confirm
I am running a set of Shinko trailmasters 120/80/18 rears and a 90/90/21 up front

Also for trail riding i want to run a 13/47 or a 13/45 because right now with the 13/42 first gear seems to low but second is two high
Can anyone confirm chain leath on a 13/47 (108) links?

I am a whole 135-140 pounds so i think ill be able to pull of the 15/39 just fine, any input would be nice THANKS!

 

OK, here we go, chain length made simple.
The 13/42 has 1/2 of each sprocket with a chain on it so it has 6.5/21 links for a total of 27.5 links hanging on the sprockets. The 15/39 has 7.5/19.5 links for a total of 27 links. Delta links is..... point 5 or 1/2 a link.
If you can run the 13/42, you can run the 15/39 by moving the rear wheel forward 1/4 a link (top and bottom added together).
My good deed for the day is done, is yours?

 

I had 14/47 with a 108, it was tight up to the front of the swinarm, but worked just fine. 13/47 will be good with a 108.

 

Awesome thank you on the chain tips i understand that now. i was a little confused because with the 13/42 my old chain was almost adjusted all the way back . but with the 15/42 it was only about half way back.
i will probably just end of running two differnt chains 15/39 with a 104 and a 13/47 with a 108

Thanks guys!

Prime, how was the 14/47 gearing ? i have been looking at the gear ratio chart and trying to figure out what to run that will give me a better gearing then a 13/42 (3.23 ratio)
how much of a difference is 3.46 and a 3.62 gear ratio and i going to feel that big of a difference between the two

 

So with this math right here in theory I can run. A 13/45 (29) and a 15/42 (28.5) on the same chain . 108 link chain if I am correct ?

 

was running 104 links for 13/39, 14/39 and 15/39....

running 106 links for 15/40...you can run 15/41 or 15/42...or, 13/42 or 14/42 also with 106 links....

i've been playing around with different sprockets and chains...

 

The 14/47 was great on the rocky, goat hill climbs we can run into around here. It let me use 2nd gear a lot more, 1st gear became pretty useless, except in the boulder fields that can pass for Class IV roads around here.
I think next time I change gearing, I'll go with a 45 out back, and have a 13, 14, and 15 front sprocket with a 106 link chain.
But for now I'm committed to going faster off-road(I need to get up to race speed), so stock will have to do.
It revved pretty high on the road with that gearing, btw.
And it almost felt like a fast bike, almost.

 

Awesome thanks prime ! I have seen A few posts that said running the 13/45 will require a 108 link chain . . Would it be that big of a difference between a 106 an a 108? The 106 I have now is the original chain and it is pretty stretched out but it easily fits the 15/42 and with the 13/42 the chain is pretty much extended all the way out

 

You are right, it should read 108. I was typing and not proof-reading.