Sprocket size followup-Thanks Jeff@z1

Only took me seven months, but I'm following up on this post regarding my sprocket changover...

kzrider.com/forum/viewthread.php?tid=27733

Particularly Jeff's help here...

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For anyone looking up this post later, I ended up taking Jeff's advice below and went with the 15/40. I'll post performance once it's running.

Jeff wrote...
...13/41 seems too radical to make sense - you'd get great acceleration, but no highway speed...

The 13/33 with 84 link 630 chain is listed as stock - ratio is 2.54:1 - straight conversion would give 15.6T front (16T), 39.6T (40T) and 100.8 links.

Improving the performance, you'd drop the front size, or increase the rear....

Available sprocket sizes limit your choices.
15T & 16T on the front are available, 38T & 41T on the back (I can get others too - these are in stock).

15T front, 38T rear gives 2.53:1 - very similar to stock
16T front, 41T rear gives 2.56:1 - just slighter lower gearing
15T front, 41T rear gives 2.73:1 - lower gearing - if you do 4500 rpm at 60 mph, them it raises the RPM to 4836 rpm at 60 mph

I should be able to get you a 40T rear - this would be a little milder in the change (2.67:1) - the 4500 rpm raises to 4730 rpm at 60 mph.

With 15T on the front and 40T on the rear, a 100 link 530 chain would fit.

Approx cost:
Rear $22
Front $14
Chain $67
total = $113 + $10 or so shipping

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Now the followup, Jeff was right on. I'm getting 4500 RPM at 55 MPH, a bit higher at 60. Thanks again Jeff.

I bought a 530 conversion from Jeff for my 900. I like it but I think I'll go to a 130/90 18 rear tire instead of the 110/90 18 I have now. That should be a nice compromise between acceleration and freeway rpm.