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Offset gearbox sprocket

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scott
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Offset gearbox sprocket

#1 PostAuthor: scott » Mon Jan 21, 2019 12:56 pm

Guys, where can i get a 5/8 offset sprocket for Gpz1100b1, 530 pitch and 16 tooth??

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Re: Offset gearbox sprocket

#2 PostAuthor: Julian_Boolean » Mon Jan 21, 2019 1:25 pm

How much offset do you want, 10mm are available from Grumpy 1260
ZZR1100s have the same splines and are 14mm offset standard.
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Re: Offset gearbox sprocket

#3 PostAuthor: ZedHead » Mon Jan 21, 2019 1:46 pm

Talon or B&C express will make them for you

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Re: Offset gearbox sprocket

#4 PostAuthor: Ginger Bear » Mon Jan 21, 2019 5:28 pm

Scott,

Are you sure you want 16 tooth with 530 chain? What size wheels are you fitting?
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Re: Offset gearbox sprocket

#5 PostAuthor: zed1015 » Mon Jan 21, 2019 6:41 pm

Ginger Bear wrote:Scott,

Are you sure you want 16 tooth with 530 chain? What size wheels are you fitting?

Yes! really need an 18/19 tooth for the chain to clear the swingarm pivot, especially if using a modern swinger with larger sections and pivot tube.
530 runs a smaller diameter for the same amount of teeth as a 630.

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Re: Offset gearbox sprocket

#6 PostAuthor: scott » Mon Jan 21, 2019 8:03 pm

The swing arm is an XJR1300, the wheels are 17" Dymags that were on my zx7r. The Dymag is fitted with a 43 tooth sprocket. Is 43 tooth ok? I was going to use 530 chain. What length chain would be best? So, 18/19 tooth for the front with some offset...i'll measure that. What is the best way to measure exactly how much offset I need? The swing arm and wheel is fitted.

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Re: Offset gearbox sprocket

#7 PostAuthor: Ginger Bear » Mon Jan 21, 2019 9:15 pm

Scott,

19t is the biggest 530 you'll get on the front & you'll need that to help your chain clear the bulkier swinger, especially if it's pushed down (longer shocks) to compensate for the smaller diameter wheels. 5/8th is the max offset before the chain starts grinding away the inside of frame above the swinging arm pivot, but you can't go any less if fitting a 180 tyre. From memory you'll need something like 38t on the rear.
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Re: Offset gearbox sprocket

#8 PostAuthor: scott » Mon Jan 21, 2019 9:19 pm

Thanks, 180 tyre fitted. So, 19 tooth with 5/8 offset. 38 tooth for the rear then. Any ideas on chain length?

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Re: Offset gearbox sprocket

#9 PostAuthor: Ginger Bear » Mon Jan 21, 2019 9:41 pm

Scott,

I take back the 38t rear, just checked my Z900 project and that has a 42t rear, probably still a little under geared. I do have a 38 & a 40t rear sprocket you can borrow if you want, but it's probably best to start large and work down. I run a GSXR 750 SRAD swinger & I had a few links spare from a 120 link chain. Are you using a ZX7R sprocket carrier?
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Re: Offset gearbox sprocket

#10 PostAuthor: scott » Mon Jan 21, 2019 10:09 pm

It’s an Aprillia RSV Dymag originally. I had Dymag machine another sprocket carrier to zx7r dimensions....sprocket wise. Hence I thought I’d try the 43 tooth sprocket on it. It’s a Talon TR 371 43 530.
I must have the 5/8, 19 tooth front for clearance reasons right? The 43 tooth on rear won’t affect clearance, right? It will only change its gearing, right? Or wrong?

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Re: Offset gearbox sprocket

#11 PostAuthor: Al » Mon Jan 21, 2019 10:14 pm

On the J1 (same gearing ratios in the box as yours) i have an 18T front and a 45T rear sprocket on an 18 inch wheel with a low profile tyre.
Its a Zephyr swingarm which i believe it more slender than the XJR and the chain taps the top and bottom of the arm on full deflection.
The front sprocket is 5/8 offset from Talon and the 530 chain taps the inside of the frame rail very lightly just as other have said above.
Given the decision again i would have had Talon make a 19 tooth front and calculated the rear size from that. At a guess that would be about 47 tooth give or take. This gearing is a fraction higher than road gearing because the bike is lighter, its 1170 etc etc etc.
Rear tyre is 160 and there is barely 10mm clearance to the chain so its going to be real tight. You may have to trim the edge off the tyre on the LHS!
Debbens used to keep a few sprockets but dont know now. They and others do chain by the length, so easy to scrap a couple of links not so good to have to join them in.
18 tooth front is also an awkward size to deal with. It has several factors unlike 19. An 18 tooth sprocket may make a future choice of rear more difficult as multiples of 2, 3, 6, 9 will occur in 45, 46 and 48 more readily!!!!!!! whir whir whir and so on.

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Re: Offset gearbox sprocket

#12 PostAuthor: Ginger Bear » Tue Jan 22, 2019 7:04 am

Scott,

Have a look at this with regard to 180 section tyre widths;

viewtopic.php?f=4&t=39423&p=332894&hilit=will+a+180+section+rear+tyre#p332894
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Re: Offset gearbox sprocket

#13 PostAuthor: scott » Tue Jan 22, 2019 7:26 am

Thanks, It's got a 180 Pirelli Diablo Supa Corsa on it. I'll try and measure its width tonight.

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Re: Offset gearbox sprocket

#14 PostAuthor: scott » Tue Jan 22, 2019 7:30 am

Any other manufactures of the offset sprocket, we have Talon and B+C Express so far?

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Re: Offset gearbox sprocket

#15 PostAuthor: Mathh » Tue Jan 22, 2019 8:58 am

VVM racing in the Netherlands make offset sprockets on request. I just ordered a 530 19T hardened with 250mm offset for 85 euros including postage.


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