Sprocket advice

12984 Views 27 Replies 9 Participants Last post by Kaw'ee, 3 d ago

Cateater

Discussion Starter · Jul 10, 2018

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?

1 - 20 of 28 Posts

Greg_E

· #2 · Jul 10, 2018

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.

Reactions: 1

Kaw'ee

· #3 · Jul 10, 2018

This should cover most of what your asking , but hit us up if not :wink2:
.
http://www.z125owners.com/forum/appearance-modifications/13738-sprockets-n-gear-ratio-choices.html

Kaw'ee

· #4 · Jul 10, 2018

Cateater said:
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?

.
Check this link for your speed-o question
'
http://www.z125owners.com/forum/kaw...speedometer-reading-errors-n-corrections.html

Cateater

Discussion Starter · #5 · Jul 10, 2018

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.

dlycan2

· #6 · Jul 11, 2018

With larger rear sprocket, chain becomes an issue.

Kaw'ee

· #7 · Jul 11, 2018 (Edited)

dlycan2 said:
With larger rear sprocket, chain becomes an issue.

.
good point dlycan :wink2:
.
With a 32 tooth rear sprocket... (stock 14 front)
.
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
.
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 ...
.
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)
.
13 or 15 tooth on the front and going bigger on the rear will change the total links required

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SqueakyHuevos

· #8 · Jul 17, 2018

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.

Greengoblin

· #9 · Jul 17, 2018

SqueakyHuevos said:
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.

colticus

· #10 · Jul 17, 2018

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.

Greg_E

· #11 · Jul 17, 2018

-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???

SqueakyHuevos

· #12 · Jul 17, 2018

Greengoblin said:
SqueakyHuevos said:

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.

Click to expand...

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.

Greengoblin

· #13 · Jul 17, 2018

SqueakyHuevos said:
Greengoblin said:

SqueakyHuevos said:

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.

Click to expand...

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.

Click to expand...

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. 🙂

Kaw'ee

· #14 · Jul 17, 2018 (Edited)

Greengoblin said:
I was thinking of doing 13 and 32. .

With 13/32 the actual GPS top speed is 54mph. but your speedo will show 66mph
.
as long as your running stock tire sizes .
.
13/32 is the preferred Wheelie gearing :wink2:
.

Greengoblin

· #15 · Jul 17, 2018

Kaw'ee said:
Greengoblin said:

I was thinking of doing 13 and 32. .

Click to expand...

With 13/32 the actual GPS top speed is 54mph. but your speedo will show 66mph
.
as long as your running stock tire sizes .
.
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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Shameless

· #16 · 11 mo ago

dlycan2 said:
With larger rear sprocket, chain becomes an issue.

Twas years ago. 1971. I had a Honda CL 450. To be quicker I went 2 teeth down on the front sprocket. No need for a new chain.

Transversely.

I’m thinking two teeth removed from the rear sprocket would increase my my top end. Also no need for a new chain.

call it Wisdom of the ancients.

Kaw'ee

· #17 · 11 mo ago

Shameless said:
call it Wisdom of the ancients.

Sleeve Font Beard Rectangle Gesture

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Sush

· #18 · 6 d ago

Cateater said:
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?

Anyone know what chain link i would need for 15T front sprocket and 35T rear sprocket ratio on the z?

Kaw'ee

· #19 · 6 d ago

Sush said:
Anyone know what chain link i would need for 15T front sprocket and 35T rear sprocket ratio on the z?

Will use a 104 link chain. (maybe even a 102 link)

Chain length calculator here for future reff;

www.z125owners.com

Chains. Ordering, Install & Adjustment, Maintenance

Chains. Ordering, Install & Adjustment, Maintenance

www.z125owners.com

www.z125owners.com

Unless you have a reason ?
Putting a higher gearing counter sprocket is defeating putting a lower gearing sprocket on the rear.
You could just put a 33T on the rear and have the same gear ratio as going 15/35
And will need a 102 link chain

Or maybe really want a 13T counter for wheelies since you want a 35T on rear .
and then will need a 102 link chain

Rectangle Font Parallel Pattern Number

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Sush

· #20 · 4 d ago

Kaw'ee said:
Will use a 104 link chain. (maybe even a 102 link)

Chain length calculator here for future reff;

Chains. Ordering, Install & Adjustment, Maintenance

Chains. Ordering, Install & Adjustment, Maintenance

www.z125owners.com

Unless you have a reason ?
Putting a higher gearing counter sprocket is defeating putting a lower gearing sprocket on the rear.
You could just put a 33T on the rear and have the same gear ratio as going 15/35
And will need a 102 link chain

Or maybe really want a 13T counter for wheelies since you want a 35T on rear .
and then will need a 102 link chain

View attachment 27786

ahh i see, huge help here. Im trying to get a bit more top speed AND more acceleration but would much rather have more acceleration over top speed for wheelies but i do want a bit more on my top speed if that would be possible. what sprocket ratio would make the most sense for that?

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