Tuesday, August 26, 2014

MODIFICATIONS: 48t to 44t Rear Sprocket

One of the complaints of my riding buddies with KLRs and VSTROMs is my lack of range on the ATK (~100 miles / tank), but another has been my comfort for running the 494 Rotax at 70 mph on the highway for any lengthy period of time (>20 minutes). I know this thing can go fast (I might have seen 95 mph before I cut back), but I just never liked the feel of running at such high RPMs for a long period of time (not only on the motor, but also on my ass). In looking at things I could do to improve my situation it looked like changing gear ratios might be the easiest and cheapest way to make 70 more comfortable.

As it was I was running 16t countershaft with a 48t rear sprocket. That equates to a exactly a 3:1 ratio. A 17t up front with a 48t in the rear would equate to a 2.82:1 ratio. A 16t countershaft with a 44t rear would be 2.75:1 ratio. A 17t countershaft with a 44 t rear would be a 2.58:1 ratio.

I decided to just go with the 44t rear sprocket to see how that affected low end torque before jumping to the 17t countershaft. From silly internet research and ZERO math I have come to understand that for every tooth increase in the front is worth 3 teeth in the rear. The 44t with my current setup would put me right at 2.75:1 ratio... That I can live with. Plus Lee told me not to mess around with a 17t, and that these bikes can do 90 all day wide open with stock gearing and why go any faster than that?

Artsy comparison of the 44t to the 48t

I will need to remove a link out of the chain since this pushed the rear axle all the way to the back of the drop out, but I am liking the speed in 5th at half throttle. I have not noticed any real change in the lower gears, torque in the corners persists despite the ratio change.

Probably won't be going to 12 o'clock any time soon, but look at that rear sprocket!!!

Rear 44t Talon Sprocket $59.99 + $15 Shipping = $74.99

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