Rears sprocket change

  • Elfarm98648
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Rears sprocket change

11 Nov 2021 12:49
#857803
Hello once again all, now that riding season is over it’s time to fix and improve the bike for next year. I have an 81KZ750 H/LTD. Right now I think I am running the original sprockets but I am unsure. I’m looking to lower RPM at higher speeds. What sprocket should I get and will it work with the standard chain? 

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  • hardrockminer
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Re: Rears sprocket change

11 Nov 2021 14:33
#857805
You can either go with a larger sprocket on the front or a smaller one on the rear, or a combination of both.  My preference is to go larger on the front.  Count the number of teeth on your front sprocket and go with either one or two more teeth, depending on how much room you have for the chain to rotate.  Another thing to watch is that the chain clears your swingarm.  You don't want it to rub.  
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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  • BobZ
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Re: Rears sprocket change

11 Nov 2021 15:03
#857807
I'd like to do the same on my 82 750 LTD...I had the cover off to change the clutch cable and it looked like there's not much room for a bigger front sprocket.  Hoping someone who's done it will chime in....
13/32 is listed as stock for mine....630 chain
Had I known I'd live this long I'd have taken better care of my Led Zeppelin albums


1983 Goldwing Interstate
1982 KZ750 LTD

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  • hardrockminer
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Re: Rears sprocket change

11 Nov 2021 20:14
#857820
A Z1 comes with a 15 tooth front sprocket but there is enough room to go up to 17, although I've never gone above 16.  If there isn't enough room on the front then the only option is to go smaller on the rear.  If stock is 13/32 that would be 2.46 ratio.  Going up one tooth on the front would give a 2.29 ratio.  But if it's too tight to fit a 14 tooth front then a 30 tooth rear would get you close to the same ratio at 2.31.  Just be aware that a smaller diameter rear sprocket might result in the chain rubbing on the top of the swingarm.  

I'm surprised they use 630 chain on the 750.  That's the same chain used on Z1/KZ1000.
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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Re: Rears sprocket change

11 Nov 2021 21:47
#857821
Well I can’t find a 30 tooth rear in 630 so looks like a 14 tooth front is our only option. I’ll look tomorrow and see what clearance is behind the cover. 

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Re: Rears sprocket change

12 Nov 2021 04:45
#857830
Any time the cover comes off is a good time to clean things up a bit!
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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Re: Rears sprocket change

12 Nov 2021 05:37
#857831
If you are changing sprockets you should also take the opportunity to rid yourself of that 630 chain. A spreadsheet can help you figure out the conversion and what you can expect your R's to be at 65 MPH. 

File Attachment:

File Name: 630 to 530...ion.xlsx
File Size:14 KB
Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
"If you didn't build it, it's not really yours"
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Re: Rears sprocket change

13 Nov 2021 19:03
#857903
Okay, I understand you. What’s the benefit to swapping to a 530 chain? Cost vs benifits? Especially considering I have a chain with only 1800 miles on it, and a rear sprocket that looks brand new. Not sure of the condition of the front sprocket but I’m sure I’ll see it soon. Definitely will be sure to clean up while I’m under there. 

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Re: Rears sprocket change

14 Nov 2021 04:44
#857907
It's a little lighter and a little cheaper.  If my chain and sprockets were new I would probably stick with what I had.
I have several restored bikes along with a 2006 Goldwing with a sidecar. My wife has a 2019 Suzuki DR 650 for on and off road.

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  • martin_csr
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Re: Rears sprocket change

14 Nov 2021 06:02 - 14 Nov 2021 06:05
#857913
By Elfarm98648:  ... Definitely will be sure to clean up while I’m under there. 

Be sure to clean up the neutral switch & terminal.  my neutral light was glitchy, so after cleaning the switch post & terminal, I crimped the terminal a tad for a tight fit >> don't crush the terminal. not sure if a replacement is available anywhere & I forget what type it is. I think Scirocco posted once but I forgot. doh.
Last edit: 14 Nov 2021 06:05 by martin_csr.

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  • Elfarm98648
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Re: Rears sprocket change

14 Nov 2021 07:49
#857920
Good tip on the neutral switch! Will for sure check it out. As far as the chain and sprockets go I think the only one I will change is the front one for now. And that’s if I have the clearance to do so. I still have not checked to see if there is clearance. Maybe sometime this week after work I’ll have enough energy to get down there 

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Re: Rears sprocket change

14 Nov 2021 08:54
#857923
I noticed a real improvement when I switched to the 530 chain. It was quieter, smoother and seemed to accelerate better. 
I always read where you are not supposed to change out sprockets individually but if they are fairly new that shouldn't be a problem for you. Changing them all does give you more options re: final gearing though. 
 
Jim
North GA
2016 Yamaha FJR1300ES
1982 GPz750 R1
1974 Kawasaki H1
1976 Kawasaki KZ400
1979 Yamaha XS650 cafe'
2001 KZ1000P
2001 Yamaha YZ426
1981 Honda XR200 stroked in an '89 CR125 chassis
1965 Mustang
1967 Triumph GT6
1976 Bronco
"If you didn't build it, it's not really yours"
The following user(s) said Thank You: Nessism

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