choosing sprockets

got a question for those more knowledgeable than me.
81 kz650 csr h1.
currently have 13 front sprocket and 33 rear sprocket with original chain. going to put new chain on.
but need to know what sprockets to put on as well.
this bike is going to be mainly (90%) highway. and want to set up for best economy possible.

thanks
jim

I'm doing kinda the opposite, wouldnt it be less teeth, smaller gear for more highway, and more teeth bigger gear for more torque? Gets confusing
Ed

If you want better economy on the highway, go for a larger front or smaller rear sprocket.

If you want to do wheelies all day, do the opposite.

Contact Jeff at Z1 Enterprises , tell him what you have and what you want it to do, and he'll hook you up.

13 33 is a 2.53 ratio
14 33 is a 2.35 ratio
13 32 is a 2.46 ratio
14 32 is a 2.28 ratio
13 34 2.61
12 33 2.75
12 34 2.83
you get the idea. for top end, bigger on the front, smaller on the back for bottom end, smaller on the front, bigger on the back

My bike runs a 16/42 combo for a 2.63 ratio. About 10 years ago I dropped 1 tooth on the front (15/42) It was a noticable difference! Bike pulled much stronger through the gears. Taking off, second gear comes up REAL fast. My rpm's went up about 500 @ 70mph. I have since went back to stock and the bike is still fast but much more civil to ride. Next time I will go UP 1 tooth on front for better highway cruising.

jccwall, 13/33? I would think having a small sprocket (front) like that would promote rapid chain wear. Your owners, Clymer or FSM will tell what it had stock. It might have been changed.

Also, if you're going to change sprockets (and chain, presumably), you should go ahead and switch to 530 (if you haven't already).

13/33, 12/34, etc is a 630 chain
16/42 is 530

I have a 630 chain and sprockets and I am 16/41. What are you saying G.G.?

You have a 16 tooth 630 sprocket on the front? That things got to be huge! Bet it's a tight fit!

How did you get it to fit? I tried a 15 tooth 630 sprocket on a 80 750 four motor and it was to big.

Why did you switch it to 630 anyway? Seems like a giant step backwards to me.

The 650's had 530 chain stock until they switched to 630 in 1981.

If you are talking about your 1000, then they did come with the 630, but I don't think a 16 tooth 630 would fit on it either, but I haven't tried it.

Post edited by: steell, at: 2008/02/24 00:09

Im so confused... Whats the difference between a 530 and 630 chain? I think I have 42 teeth on my rear sprocket, but I probably miscounted. If I wanted a little more torque witout making too big of a change, what should I do chain and sprocket wise? Thanks,
-Ed

CptEDIV wrote:

Im so confused... Whats the difference between a 530 and 630 chain?

630 to 530 chain conversion guide

Chain type and size guide

Changing sprocket sizes guide

I think I have 42 teeth on my rear sprocket, but I probably miscounted. If I wanted a little more torque witout making too big of a change, what should I do chain and sprocket wise? Thanks,
-Ed

Figure out your stock ratio, then go from there. A bigger back sprocket will give you more low end torque, so maybe go up a couple teeth. Contact Jeff Saunders at Z1 Enterprises , tell him what you have and what you want it to do and he'll hook you up.

CptEDIV, do you have an owner's manual? If so it will tell you what your stock chain specs are. Like GG says, you can go up a couple teeth on the rear or drop one tooth on the front as I did. This will raise your highway rpm's by about 500 but will pull harder around town.

Steell, the 650's came back with the 630 in '81? Why would they go back to "beta" when "vhs" had proven itself?

Bluemeanie wrote:

Steell, the 650's came back with the 630 in '81? Why would they go back to "beta" when "vhs" had proven itself?

A "Giant Step backwards" in terms of performance and technology, as prior to 81 the 650's had always used 530 chain.

I was giving kzwolfsr the benefit of doubt and assuming he was correct in saying "he" has 630 chain on "his" 650, while I actually think he is mistaken.

630 chain development stopped years ago while 530 and others kept improving, I think the last improvement to 630 chain was the O-ring while 530 and 525 passed the 630 in terms of tensile strength some years ago. I don't believe that any current model motorcycles sold today use 630, I think that even the ZX14 uses 525 (skinny version of 530).

Kawasaki went to 630 chain on the 650's when they merged the 650 and 750 into one motor in 81 (81 650 is simply a 750 with a smaller bore from 81 on), that's why the 650 lost the kickstart and the 750 cylinder block will bolt right on any 650 that didn't come with a kickstart (no case boring required, and it has a HyVo cam chain).

530 is 5/8" pitch (distance between teeth)
630 is 3/4" pitch.

16 x .625 = 10" circumference of sprocket
16 x .75 = 12" circumference of sprocket

10" divided by pi = 3.18" diameter
12" divided by pi = 3.82" diameter

So a 16 tooth 630 sprocket is .64" inches larger in diameter.

That means that the 650 must have at least approximately 1/3" (.32" to be exact) clearance between the chain on the sprocket and the metal guard (or shift shaft, clutch pushrod, or anything else) with a 530 16 tooth sprocket before you can change it to a 16 tooth 630 sprocket.

Just for comparison:

19 tooth 530 sprocket is 11.875" inches in circumference, 3.79" in diameter, just a hair smaller than a 16 tooth 630 sprocket.

Any of you folks with 650's ever tried to put a 19 tooth 530 sprocket on a 650?

I have a 83 GPz750 motor (in a 650SR) in the garage with a 18 tooth 530 sprocket on it, and 19 tooth might fit, but being a 83 GPz750 motor it doesn't have the clutch pushrod, stock was 15 tooth 630.