front sprocket sizes

lol my frankenkaw, the only one I got

Godfrey wrote: yeah the tire is a 130/90 16, not a stock 650 rim

Actually, that is the stock tire size for a 1981 KZ650-H1 (CSR).

Godfrey wrote: lol my frankenkaw, the only one I got

Ok what do you see as the usable powerband of Frankie? Where is the lower end of the torque? You don't want to gear so tall that you can get across the intersection without smoking the tire. Also it is always a compromise. Lose accel, and gain speed/ cruising RPM lowers. Fuel mileage would increase, if a good selection is made. One thing about front sprockets is they are cheap enough to try one out. Then if it is to much your only out like $20. Could even be resold for near what it cost if you don't ride it long.

well I'll be, Ed, all I know is what my tach tells me, 5 k at 60 mph, 4500 at 55

Like I said, Motorhead, the 15 tooth is physically too big to run with the lil guard for the countershaft in place,so I am out $25, and so far unless I buy a custom back sprocket the smallest stock one is a 32, everywhere I've looked.

Well I did read that, and If you were trying to work out the ratio, could you run without said guard for a bit to see. The guard might be needed on an old chain sprocket set that's worn out, as it may come lose. Or if the counter shaft sprocket nut was not installed properly. I've yet to need one, although it is installed. Definitely up to you. Then with those conversions from the 630 to 530, maybe all fits nicely? I couldn't say. Whats a custom rear in your choice of teeth and chain go for?

ok I didn't really answer your question, with the stock gearing it pulls decent from idle right on up, ya hit 5 grand and if the throttles cranked , hold on, so I would say 5-10k. I just don't think 43-4500 at60 mph is that far off. But I been wrong before.

Well I would say I am about 4500 @65 with my 82 1000 LTD, with a 1 up counter shaft=15, and a one down on rear=38 with 630 chain. Then a 130/90-16 rear, that it requires some clutch slipping to get going. The off the line accel is of course effected. But since I like to get out of town and ride, and tour, been 11K' back to sea level, the Hi-way gears are what I prefer. I still have a smooth Idle and good low end, since the motor is stock with the 4-1 V&H. I would think that your bikes powerband would have moved up the RPM range a ways. So you would not really like these ratio's unless out on the road, the majority of time. But only you could be the judge of that, your Frankbike.

The whole objective of doin this transplant was to have a bike that would carry my fat ass 23 miles to work every mornin on the highway during the summer. I've considered swappin out the stock.308 lift cams from the 650 into this engine for a more useable powerband, just not sure what new problems I'd run into, and then this issue with gearing rears its head.

Godfrey wrote: well I'll be, Ed, all I know is what my tach tells me, 5 k at 60 mph, 4500 at 55

Since the tire and the 13/33 sprockets are stock size I wonder if there are some gear ratio differences within the 750 transmission that account for the high rpm at 60 mph? Or it could be the tach is not accurate, you may want to check it with a dwell meter tach or some other electronic tach. The speedo may not be accurate, but they generally read higher than actual, not lower. The other possibility is the clutch could be slipping a little. Ed

Trans are the same except for turbo.
I have a '78 KZ650sr/738cc,pipe,vm24s and pods with 16/38 sprockets(530).
It's a little weak off the line and top end is not improved that much.
13/33(630) = 2.538/1
16/40(530) = 2.5/1(most stock 650's)
16/38(530) = 2.375(tallest rear commonly available)
530 - 13 to 17,38 to 42 if I remember right

Well the books I have say 5th gear in the 650 is .89 and in the 750 .87 so not enough to make that much difference; the speedo could be off, and or the clutch could be slipping I suppose, not sure(not sayin it can't happen)I've ever heard of a mechanical tach bein off. Regardless, I put the 13 tooth sprocket back in and put it all back together, there doesn't look to be enough room for anything bigger.If I pursue this any further I will have to focus on a custom rear sprocket.