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Discussion Starter · #1 ·
Hey all i have been reading alot about sprocket changes people have done and was wondering if it would be right for me. Currently, the fastest my Z has ever gotten (downhill with tailwind) was 64. And I'm a pretty light dude at 125 pounds. It has never hit rev limiter at 4th gear because it just doesnt have the grunt to get there, and getting from 56-61 takes forever. So i was thinking about going down a tooth in the front to give it some more push. I realize this will decrease top speed, but with how it is now, I never even get all the way to redline anyways because of the lack of torque. In a perfect world, I was hoping this sprocket change would get me to about the same speeds I'm getting now or maybe slightly lower, just at a higher rpm but with the more fun in the low/mid range that comes with the torque. Will it completely kill my top speed? I'm not sure how drastic the sprocket changes are. I also read that it will screw with the speedometer, but I thought that the speedometer read from wheel rotation not sprocket? even if it does, would it make the speedo reading more accurate? or worse?
 

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The speedo is read from the final output gear in the transmission, so a lot of things screw it up. I have a correction device, but haven't put it on yet.

A 13 tooth gear would be one lower, but might be too much, not sure because I haven't put mine on yet either. It might need the stock 14 gear in the front, and a rear gear with a couple extra teeth to do what you want.
 

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Discussion Starter · #5 ·
Thanks for the info guys! definitely cleared stuff up about the speedo. I guess the best thing to do about the sprocket is trial and error and see what I like best. Kinda leaning towards the 32 rear. The things aren't expensive so even if i hate it and go back to stock, its no big deal.
 

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With larger rear sprocket, chain becomes an issue.
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good point dlycan :wink2:
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With a 32 tooth rear sprocket... (stock 14 front)
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A Chain calculator will show a 101 link , and nobody wants to use a 1/2 link . So as long as your near the third notch back you should be able to slide the adjusters forward and use the stock 100 link chain
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When changing the front to a 13 tooth , A Chain calculator will show a 99 links (actually needs to to shorter) but again, should be able to use the stock 100 link chain using the adjusters ...
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With stock 14 tooth front sprocket.
30 tooth rear sprocket needs a 100 link chain
34 tooth rear sprocket needs a 102 link chain
38 tooth rear sprocket needs a 104 link chain
(Chains only come in equal number links)
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13 or 15 tooth on the front and going bigger on the rear will change the total links required
 

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I've run a 32 with the stock front and stock chain. it fits, but very little adjustment is left. Theres still enough slack for adequate swingarm travel.

Acceleration was nice! I liked it alot, but top end suffered badly and I always felt like I needed a gear between wnd and 3rd in the twisties. A 31 rear on mine is near ideal. A slight, but very noticable increase in low end grunt and only a loss of about 4 mph on the top.
 

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I've run a 32 with the stock front and stock chain. it fits, but very little adjustment is left. Theres still enough slack for adequate swingarm travel.

Acceleration was nice! I liked it alot, but top end suffered badly and I always felt like I needed a gear between wnd and 3rd in the twisties. A 31 rear on mine is near ideal. A slight, but very noticable increase in low end grunt and only a loss of about 4 mph on the top.
So what was your top end with 32 sprocket? I was thinking of doing 13 and 32. I would like to make the front end come up easier on 2nd gear wheelie.

I have a 13 now and my speedo is off by 5 mph.
 

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Stock sprockets setup was best for me. Went a size taller tire in the rear and went +2 in the rear to get as close as stock ratio as possible.

All other sprocket combinations sucked. -1 was completely horrible. Felt faster until I raced my buddies stock z and it walked me hard from pretty much the start. Went back to stock and was dead even.
 

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-1 in the front should have given you better acceleration, made a huge difference on my KAYO and let me get into 5th on the straights where before I was only approaching 5th at the end of the straight.

Might have to rethink what I was going to try with my Z. I know eventually I want to go 120/80 rear tire, maybe I need to run the larger tire with the stock front sprocket???
 

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I've run a 32 with the stock front and stock chain. it fits, but very little adjustment is left. Theres still enough slack for adequate swingarm travel.

Acceleration was nice! I liked it alot, but top end suffered badly and I always felt like I needed a gear between wnd and 3rd in the twisties. A 31 rear on mine is near ideal. A slight, but very noticable increase in low end grunt and only a loss of about 4 mph on the top.
So what was your top end with 32 sprocket? I was thinking of doing 13 and 32. I would like to make the front end come up easier on 2nd gear wheelie.

I have a 13 now and my speedo is off by 5 mph.
My speedo was off and I never used a gps to verify what it was. But it couldn't hang with a friends stock z on long straights. I'd walk him pretty hard til mid 4th gear, then he'd start making up distance and end up walking me. When I hit the limiter, he was still pulling.
 

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I've run a 32 with the stock front and stock chain. it fits, but very little adjustment is left. Theres still enough slack for adequate swingarm travel.

Acceleration was nice! I liked it alot, but top end suffered badly and I always felt like I needed a gear between wnd and 3rd in the twisties. A 31 rear on mine is near ideal. A slight, but very noticable increase in low end grunt and only a loss of about 4 mph on the top.
So what was your top end with 32 sprocket? I was thinking of doing 13 and 32. I would like to make the front end come up easier on 2nd gear wheelie.

I have a 13 now and my speedo is off by 5 mph.
My speedo was off and I never used a gps to verify what it was. But it couldn't hang with a friends stock z on long straights. I'd walk him pretty hard til mid 4th gear, then he'd start making up distance and end up walking me. When I hit the limiter, he was still pulling.
Sounds about right. Since you gain acceleration you will loose top speed.

I do not race this bike even though I know it would be tons of fun. I just wanna be better on second gear wheelies then I can move on to do it to my other bigger bike. 🙂
 

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I was thinking of doing 13 and 32. .
With 13/32 the actual GPS top speed is 54mph. but your speedo will show 66mph
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as long as your running stock tire sizes .
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13/32 is the preferred Wheelie gearing /forum/images/Z125owners/smilies/tango_face_wink.png
.[/QUOTE

Awesome! Thank you. The actual mph is not too bad.

I am probably going to be much slower than that since I have a 130 tire width in the back. 🙂
 
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