kz750 twin sprocket

I'm wanting to get my '80 kz750-g1 to run at a more comfortable rpm on the interstate. has anybody changed sprockets on one of these bikes with this in view (steell?)? any suggestions on what sprockets to use and where to get them? Thanks in advance guys.

17 tooth countershaft sprocket works well, many here (including me) use it.

Z1 Enterprises is where I buy mine.

Yep

jorn wrote:

I'm wanting to get my '80 kz750-g1 to run at a more comfortable rpm on the interstate. has anybody changed sprockets on one of these bikes with this in view (steell?)? any suggestions on what sprockets to use and where to get them? Thanks in advance guys.

I am running the 16T standard front with a 32T rear. 32T is the smallest you can go in the back. That gives a 2.00:1 ratio. If you go from 16T to 17T on the front, that's only about a 6% reduction in RPM and Id efinitely wanted more than that. Going from 38T to 32T in the back drops the RPM about 16%. For me, that dropped 70mph RPM from 5000 down to about 4200.

I didn't see any reason to buy two sprockets to change the gearing, so I just changed the back.

I am totally happy with the performance, but I weight 165 and don't hot rod much.

I recall I got mine from a place that had a name like "sprocket specialties" or maybe "sprocket specialists" or something that sounded like that. It is a hardened aluminum sprocket as opposed to steel but it wears forever so it must be good.

steell wrote:

17 tooth countershaft sprocket works well, many here (including me) use it.

Z1 Enterprises is where I buy mine.

(Including me, too.)

:laugh:

Guess I should clarify

I used a 17 tooth countershaft sprocket on all the 750 twins I have had, but they have all had 16" rear wheels, either Morris Mags or the G rear wheel. And Morris Mags use a 37 tooth rear sprocket stock.

ok. i'm using the stock mag, and she cruises at 75 at right around 6k rpm. it hurts me inside to run her like that.

i'm not sure how to calculate the rpm drop, but i was thinking about going with the 18-tooth countershaft to start out with and if that didn't drop it enough to try reducing my rear sprocket size. will the 18-tooth fit alright/

please pardon my broken shift keys. that sentence was meant to be a question :laugh:

17 is a fairly tight fit, to use an 18 you'd probably have to remove the guard in front of the sprocket.

75 mph has been the "sweet spot" (the speed at which everything just feels right) on my 750 twins with the 17/38 or 17/37 sprockets and 16" rear tires.

jorn wrote:

ok. i'm using the stock mag, and she cruises at 75 at right around 6k rpm. it hurts me inside to run her like that.

i'm not sure how to calculate the rpm drop, but i was thinking about going with the 18-tooth countershaft to start out with and if that didn't drop it enough to try reducing my rear sprocket size. will the 18-tooth fit alright/

please pardon my broken shift keys. that sentence was meant to be a question :laugh:

Easy to calculate the RPM drop: if you start with a 16T front and go up 1T, the RPM will drop by 1/16 or the final RPM will be 15/16 of the original.

If you start with a rear of 38T and go to 32T (like I did), the RMP will drop by 6/38, or final RPM will be 32/38 of original.

BTW, mine cranked 5000 @ 70MPH stock, so it dropped to about 4200 RPM @ 70MPH after changing the rear sprocket from 38T to 32T.

I don't think an 18T will fit on the front, I know a 32T fits on the back because I am running one now.