JT rear sprocket which way? - Wrist Twisters
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Old 06-01-2017, 04:37 PM Thread Starter
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JT rear sprocket which way?

My new JT front sproket is wearing on the inside and the JT rear is wearing on the outside. The first pic shows the inside of the sprockets and the second pic is the outside. I have aligned front and back wheels till I'm blue in the face I cannot centre the chain on both sprockets. The rear JT sprocket has concave machined side and a flat side. When first fitting I assumed the concave side with the markings was to be mounted facing out. The front sprocket looked like it could go either way since the central hub was equal on both sides. After a thousand km's I've noticed the wear. It is like the rear sprocket isn't in line with the front. So I flipped the rear around. Now the concave side faces into the wheel. This has shifted the centre of the rear sprocket in a few mm. The chain now sits central on both sprockets.
Is anyone else running JT sprockets and noticed this? Does a rear sproket with a concave machined surface have a correct mounting position?
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Old 06-02-2017, 10:45 AM
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Quote:
Originally Posted by Islandboy View Post
My new JT front sproket is wearing on the inside and the JT rear is wearing on the outside. The first pic shows the inside of the sprockets and the second pic is the outside. I have aligned front and back wheels till I'm blue in the face I cannot centre the chain on both sprockets. The rear JT sprocket has concave machined side and a flat side. When first fitting I assumed the concave side with the markings was to be mounted facing out. The front sprocket looked like it could go either way since the central hub was equal on both sides. After a thousand km's I've noticed the wear. It is like the rear sprocket isn't in line with the front. So I flipped the rear around. Now the concave side faces into the wheel. This has shifted the centre of the rear sprocket in a few mm. The chain now sits central on both sprockets.
Is anyone else running JT sprockets and noticed this? Does a rear sproket with a concave machined surface have a correct mounting position?
Does your JT front sprocket have the same hub width as stock, or is it a bit narrower?

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Old 06-02-2017, 01:12 PM
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Did you try contacting the manufacturer?

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Old 06-02-2017, 05:16 PM Thread Starter
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Mcromo44, I've thrown my OEM front sprocket away so I can't compare hub widths. I suspect the stock sprocket sat further away from the engine, ie it has a thicker inner hub and can only go one way. JT rear sprocket with the concave side facing out caused the chain to want run further out than the JT front sprocket would allow. So it would rub on the inside of the front sprocket. If I remove the front sprocket retaining bolt the front sprocket would want to move out when spinning wheel. Now I have reversed rear sprocket and it all lines up much better. There was some noise from the front sprocket before the swap now it's mostly gone. I'm thinking on getting a silent front sprocket (has some rubber on it) but it would have to be a 17 tooth.
Gary 900 I have contacted JT but haven't heard back from yet. Thanks guys.

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Old 06-02-2017, 06:44 PM
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Quote:
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Mcromo44, I've thrown my OEM front sprocket away so I can't compare hub widths. I suspect the stock sprocket sat further away from the engine, ie it has a thicker inner hub and can only go one way. JT rear sprocket with the concave side facing out caused the chain to want run further out than the JT front sprocket would allow. So it would rub on the inside of the front sprocket. If I remove the front sprocket retaining bolt the front sprocket would want to move out when spinning wheel. Now I have reversed rear sprocket and it all lines up much better. There was some noise from the front sprocket before the swap now it's mostly gone. I'm thinking on getting a silent front sprocket (has some rubber on it) but it would have to be a 17 tooth.
Gary 900 I have contacted JT but haven't heard back from yet. Thanks guys.
If the front sprocket is making noise, it's for a reason. Getting anything that has a sound dampener is going to simply cover up the problem.

I'm kinda surprised that a sprocket wouldn't have markings on it, I haven't looked at my kit, it's the 17/44 kit sold here, but I would have expected that this wouldn't be a question.

EDIT: I just pulled out the kit from some 4 years ago, no instructions. The front has marking on one side, the rear has a slight inset on one side. I guess I'll have to measure when I get around to installing it.

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Old 06-02-2017, 07:16 PM Thread Starter
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KarlJay, I think all chain and sprocket systems make a noise, no matter how perfectly lined up. Especially the front, smaller diameter, sprocket. That's why the OEM front sprocket has a rubber sound dampener. Of course any misalignment would increase noise. You can even get silenced rear sprockets now. I will try to find a 17t silenced front sprocket, I don't think I could go back to 16t. No installation instructions for my JT sprockets. All seems good now. Thanks mate.

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Old 07-03-2017, 09:30 AM
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Islandboy, thanks again for your tip on changing sprockets and chain . . . . which brings me here, coincidentally.
Strange how many various suppliers say they're either out of stock on 919 sprockets or don't carry them! So hunting down is a bit of a challenge.

Curious why you prefer 17 tooth in front and that you'll never go back to a 16. Better acceleration perhaps?
And what number teeth on rear sprocket do you recommend?

btw, I think you right on about noise coming from bad sprockets and chain. I just noticed a lot of lateral play of chain on rear sprocket, even after having just perfectly tensioned!

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Old 07-03-2017, 11:29 AM Thread Starter
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Ok. If your in the states LDH might supply you with a 17/44 tooth sprocket and chain set. Less acceleration with the 17/44 combo. What it does is remove some 'buzz' from the bike at highway speeds. I didn't notice any loss of acceleration but felt the bike in top gear was better matched in revs and speed. Just felt better. Although I've read post where some have preferred the stock setup and some have even gone the other way for more acceleration. I'm pretty sure around here somewhere is a thread or two on said benifits of the 17/44 combo. Also there is a different chain size recommend as well. I just stuck with the stock size chain, gold DID. I live in Australia so just went with what I could get at a good price. Now I have reversed the rear JT sprocket I'm pretty happy with my setup, although I would say that JT was at the cheaper end. Been trying to find a silent 17t front sprocket but no luck.

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Old 07-03-2017, 07:13 PM
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Ok. If your in the states LDH might supply you with a 17/44 tooth sprocket and chain set. Less acceleration with the 17/44 combo. What it does is remove some 'buzz' from the bike at highway speeds. I didn't notice any loss of acceleration but felt the bike in top gear was better matched in revs and speed. Just felt better. Although I've read post where some have preferred the stock setup and some have even gone the other way for more acceleration. I'm pretty sure around here somewhere is a thread or two on said benifits of the 17/44 combo. Also there is a different chain size recommend as well. I just stuck with the stock size chain, gold DID. I live in Australia so just went with what I could get at a good price. Now I have reversed the rear JT sprocket I'm pretty happy with my setup, although I would say that JT was at the cheaper end. Been trying to find a silent 17t front sprocket but no luck.
How do you tell if a sprocket is silent or not?

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Old 07-03-2017, 08:08 PM Thread Starter
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The silent sprockets have a rubber band that runs around both sides of the sprocket right about where the bottom of the chain sits. I think the stock front sprocket is a silent type? I've thrown mine away so can't check. I believe the theory is they remove some chain settling noise as it runs along the sprocket. I've only seen front 16t silent sprockets although have read somewhere there is a rear as well. I get most of my chain/sprocket noise at the front so would like to get a silent sprocket for there, but really want a 17t. Honestly I don't know how much noise they remove but I reckon any reduction is an improvement. There's a few on ebay.

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Old 07-05-2017, 03:28 PM Thread Starter
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So I found a 17t silent front sprocket on ebay.
http://www.ebay.com.au/itm/151862346545
The description doesn't list the 919 as compatible but the supplier says it will fit. Just thought I might check with you guys. Does anyone know if the front sprocket of a cbr1000 would fit the 919?

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Old 07-05-2017, 08:54 PM
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Quote:
Originally Posted by Islandboy View Post
So I found a 17t silent front sprocket on ebay.
Silent Pinion 17 Teeth Honda CBR 1000 For,CBR1000F,SC21,SC24,339-17,sprocket
The description doesn't list the 919 as compatible but the supplier says it will fit. Just thought I might check with you guys. Does anyone know if the front sprocket of a cbr1000 would fit the 919?
According to the AFAM packaging I kept from my 520 conversion, my front AFAM sprocket for and on my 919, is also suitable for a string of Hondas including the "CBR 1000 RR".

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Old 07-06-2017, 12:43 AM Thread Starter
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Thanks Mcromo. Yep I've seen that also on various sprockets advertised about. Lots of various compatibility. All seems a bit willy nilly though. Bit worried but bugger it ,only one way to find out. Don't know how much noise they remove and I also wonder if they get less effective at noise reduction over time. I'd imagine that rubber dampener would impact over time. l might get one and I'll let ya know what I think.

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