45t/16t gearing on a kz650 for city driving?

Hi all. My sprockets and chain need to be replaced. 90% of my driving is done in new york city, so I am constantly in fairly slow stop and go traffic, and am rarely on highways. Stock gearing is 42/16. I thought I'd take it up a bit to 45/16. Does that sound about right to people?

Going from a 16 to 15 tooth front makes my 650 feel much stronger outta the hole and around town..... thinking you will like it...... raises 65mph revs around 500rpm or just under but as you say the majority or your riding is around town anyway ... 16/45 is almost exactly the same as a 15/42.

KZB2 650 wrote: Going from a 16 to 15 tooth front makes my 650 feel much stronger outta the hole and around town..... thinking you will like it...... raises 65mph revs around 500rpm or just under but as you say the majority or your riding is around town anyway ... 16/45 is almost exactly the same as a 15/42.

1) Ah, that's great to hear.
2) oh, that's interesting. I actually have the a new 16t front, 42t rear sprocket, and 102 link chain. I just bought stock before thinking. My proposed swap means I need to swap out the chain (for a 104 link) and the rear sprocket, whereas 15/42 means I can keep the chain and rear, and just exchange the 16 for a 15. Any problems here?

Might wear a "little" faster is all but in your case I'd do it and just be sure to keep it well oiled.

KZB2 650 wrote: Might wear a "little" faster is all but in your case I'd do it and just be sure to keep it well oiled.

Thanks. Thoughts on 42/15 vs 45/16?

Theoretically, the chain tension on the top side will be a tiny bit higher on the 15/42, than the 16/45 during acceleration etc. Chain tension does affect the anti-squat effect during acceleration. (Google anti-squat geometry motorcycle if you want to know more about it.) Also, because the front sprocket diameter is a tiny bit smaller, the chain will have a tiny bit less clearance where it goes over the swingarm pivot.

With stock ride height and normal chain adjustment, the difference will probably be too little to matter.

If your suspension is raised up, and your chain is already rubbing the swingarm pivot, it could be an issue.

I wouldn't go smaller in the front. Go larger in the back...or keep it stock. Smaller in the front forces the chain to turn through a smaller diameter and that costs power and increases wear.

Nessism wrote: I wouldn't go smaller in the front. Go larger in the back...or keep it stock. Smaller in the front forces the chain to turn through a smaller diameter and that costs power and increases wear.

+1 I would keep the 16T size sprocket up front. Ed

loudhvx wrote:
With stock ride height and normal chain adjustment, the difference will probably be too little to matter.

1980 KZ750E uses a 13 tooth front....... are you sure you would need a 104 link chain if you went with a 45 T rear not sure but would be defently more $$ regardless ???

Not to mention this is the first mod recommended by Denco (15T front) back in the day.

KZB2 650 wrote:

loudhvx wrote:
With stock ride height and normal chain adjustment, the difference will probably be too little to matter.

1980 KZ750E uses a 13 tooth front....... are you sure you would need a 104 link chain if you went with a 45 T rear not sure but would be defently more $$ regardless ???

Not to mention this is the first mod recommended by Denco (15T front) back in the day.

I didn't say all that. I don't know where you got that quote, but I'm shocked to hear a 750 had a 13T sprocket.

loudhvx wrote:

KZB2 650 wrote:

loudhvx wrote:
With stock ride height and normal chain adjustment, the difference will probably be too little to matter.

1980 KZ750E uses a 13 tooth front....... are you sure you would need a 104 link chain if you went with a 45 T rear not sure but would be defently more $$ regardless ???

Not to mention this is the first mod recommended by Denco (15T front) back in the day.

I didn't say all that. I don't know where you got that quote, but I'm shocked to hear a 750 had a 13T sprocket.

True Loud....... ment to only use the first line you wrote but for some reason what I wrote on the next 2 was lumped in with it.

. wrote: ..........1980 KZ750E uses a 13 tooth front......

Keep in mind that the 13 tooth sprocket on the 1980 KZ750E has a larger diameter than one would have on a KZ650. This is because the stock chain size on the 1980 KZ750E is 630 but on the KZ650 it is 530. Consequently, the distance between chain pins on the KZ750E chain are longer (3/4") than on the KZ650 (5/8"). Ed