I think I bought the same sprocket from RMATV. I didn't notice it was rubbing the engine case until I took the sprocket off. It had only rubbed a little bit. If you had the tools at your disposal you could make an additonal spacer to get the clearance you need. I took the 12t off because I didn't like the way it felt. It had a little quicker snap to it, but then nothing to back it up. The ratio of a 12/42 (3.5:1)and a 13/45 (3.46:1) is nearly the same. A lot of factors come into play finding the gearing that works for you. I know form running the 12/42 that I wouldn't like the 13/45. Deej is a bigger guy, maybe the 13/45 gearing feels the same to him as the 13/42 feels to me. I would try to find a spacer for your 12t to see if you like the feel before you spend a bunch of money on a chain and a 45t to get the same ratio as the 12/42. For me my money is on the 13/42.
Also, I wouldn't get my panties in a twist worrying about the smaller dia of the 121t. Put it on, run it, and see if you wear out a chain a lot faster. Sure it's technically harder on the chain, but is it that much harder on it? Your chain has to deal with things that do more damage than a small sprocket will.
Dan

 

Thanks for all the responses! You guys have talked me into the new chain and rear sprocket route. I ordered a 108 link chain and a 47t rear sprocket from RMATV. That way I figure I can use the 14/47 combo for the limited street riding that I do, and 13/47 for the dirt. I would have gone for a 46 if I could find one for less than $55.

My issue with gearing hasn't been with grunt as much as stall speed. Last time I was riding tight dirt trails with the 13/42 combo I felt like I didn't get out of first gear all day, and I was doing a lot of clutch feathering. So I need more of a granny gear, especially for downhill sections.

maninthesea: I'm not ready to give up my stock 42 just yet, but if I do it's yours.

 

Sorry to burst your bubble but no-one said you need a 108 for that combo, it was a 108 for the 45 rear, for the 47 you will need a 110

 

According to this post by The Mekon
https://www.kawasakiforums.com/forum...=sprocket+gear
a 108 will work for 13/47 and 14/47, the "magic number" for the 108 chain being 60 +/-1.

Is this incorrect?

 

Hmm, that would be close but should just fit. I ran a 14/49 w/110 link and had lots of room....now I run a 14/45 with a 108 ...... the 108 may fit a 47.

Ok who's done it? Post up

 

when and where are you riding?

 

Gobius
Thanks for putting me in line. It looke like I will be getting a new sprocket soon. I can see wear on my rear.
Cheers Jim

 

Walker Valley and Tahuya mostly. This time of year Walker is pretty snotty and therefore a bit technical for me (I'm pretty much a noob in the dirt), so I prefer Tahuya. Only problem there is the giant water holes. I hope to be getting out a lot more often after the quail season closes over on the dry side.

 

Count the links? Who has time for that?

I have 14/47, but I just installed the chain, set the axle alignment, and cut off the excess when I was satisfied with the chain slack and axle alignment. I always see these posts about folks buying new chains and wanting to know the exact chain link number. I buy a chain that I know is longer and then just bench grinder the excess length. The slightly longer chains don't cost any more that I've seen. Am I missing something?

 

I guess if it works, I selected to buy the tool that presses the chain apart.
pretty soon I'll have an extra chain