Author Topic: Gearbox countershaft sprocket  (Read 2018 times)

Offline Hubie

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Gearbox countershaft sprocket
« on: 28.02. 2010 06:16 »
G'day all,

Just wondering what the standard size sprocket is for the A10 flash and where I can get a bigger one.

Cheers

Hubie
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Online groily

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Re: Gearbox countershaft sprocket
« Reply #1 on: 28.02. 2010 08:03 »
Pretty sure it's a 19 Hubie (it's what I took off mine anyway). I got a 20 from either SRM or Draganfly, I forget which. There are larger sprocket options if you've got the power and not the weight - but some of them require fitting rear sets as there isn't the room for a very large sprocket with the standard footrests in place. I think 21 teeth is the practical limit, someone else will know for sure. My engine is in standard Flash state of tune and I live in the middle of nowhere, so town riding is rare and the extra gearing is OK. For me, it makes cruising on empty roads better and gives just a little extra length to 2nd gear, which I always moan is too low in STD boxes. But I think that's just me.
On mine, I found the extra tooth gave me a chain-pain - had to fit a cranked link in the rear as the primary was also new and the gearbox was fully forward. The brand-new rear was just that tiny bit too tight to get the correct amount of slack. After a fair few miles and a small amount of adjustment on the primary, my newest new rear chain is the correct 98 links and fits nicely.
Bill

Offline Hubie

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Re: Gearbox countershaft sprocket
« Reply #2 on: 01.03. 2010 04:36 »
Hi there Grolly,

Checked mine last night and it is a 19 toother.  Might have to pick up a 21 for it, give it a little more freeway legs.  Either way it's going well.  Anyone here using iridium plugs on their bikes???
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline chaterlea25

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Re: Gearbox countershaft sprocket
« Reply #3 on: 01.03. 2010 18:50 »
Hi Hubie,
What crankshaft sprocket is fitted to your bike?
Its less work and more normal to change the engine sprocket!!
crankshaft sprockets range from (from memory) 17 tooth for side car to 24 tooth option for RGS
HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Online groily

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Re: Gearbox countershaft sprocket
« Reply #4 on: 01.03. 2010 20:42 »
Tis true John, 'tis all true. But final drive sprockets are cheap and cheerful if the whole primary side is off anyway!
Bill

Offline Hubie

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Re: Gearbox countershaft sprocket
« Reply #5 on: 05.03. 2010 07:51 »
Hi Groily,

Npt sure what size the engine sprocket is but I do agree it would be less work to change it than the gearbox sprocket.  My assumption is to obviously go a couple more teeth to achieve the same outcome?

Cheers,

Hubie
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline Hubie

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Re: Gearbox countershaft sprocket
« Reply #6 on: 05.03. 2010 08:42 »
Just out of curiosity, as I have not been able to find it whilst surfing, what is the standard size of the engine sprocket for solo use?

Cheers

Hubie
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline chaterlea25

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Re: Gearbox countershaft sprocket
« Reply #7 on: 05.03. 2010 22:35 »
Hi Hubie,
I think it depends on year and model, Not 100% sure on this
HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline trevinoz

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Re: Gearbox countershaft sprocket
« Reply #8 on: 05.03. 2010 23:05 »
Swinging arm A10 is 21 teeth.
Trev.

Offline Hubie

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Re: Gearbox countershaft sprocket
« Reply #9 on: 06.03. 2010 09:00 »
Might go to 23 teeth then!  All I will need is a new primary cover gasket....
1959 BSA Golden Flash
1956 Royal Enfield Super Meteor
1955 Royal Enfield 350 Bullet
2007 Harley Davidson Sportster 1200 Custom

The early bird gets the worm, but the second mouse get's the cheese!

Offline trevinoz

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Re: Gearbox countershaft sprocket
« Reply #10 on: 06.03. 2010 21:07 »
And primary chain and will probably be over geared.
The subject of gearing has been well covered over the years.
I just use standard gearing and find the bikes nice and responsive with it.
You may feel that your bike is revving too hard at 60 MPH but revs wont hurt it.
Trev.

Offline chaterlea25

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Re: Gearbox countershaft sprocket
« Reply #11 on: 06.03. 2010 23:11 »
Hi Hubie and All,
I'm running a 23 tooth on my SR, no worries
My  bike never seem over geared, I also have a 24 I must try sometime
The other factor to consider is the rear tyre size, it makes quite a difference
I'm using a 100/90
HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline brackenfel

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Re: Gearbox countershaft sprocket
« Reply #12 on: 07.03. 2010 16:13 »
John,
Does the tyre make a significant difference?  I'm going to change the 4.10 SM Mk2 for a 100/90 & hadn't considered it might alter the gearing. Am going to do it anyway though as I don't like the "old style" Avon tyres, going for Roadriders instead..

Cheers,

Adrian
1961 A10 650 Golden Flash - Blue
1954 BSA B33
Velocette Viper
Laverda 750 SF1
Kawasaki W650
Buell XB9S
Ariel 350NH & Matchless G3LS in bits...

Offline chaterlea25

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Re: Gearbox countershaft sprocket
« Reply #13 on: 07.03. 2010 20:23 »
HI Adrian,
I can feel the difference anyway!!!!
I can also "feel" the diff when a new tyre is fitted
There are very positive reports on the "Roadrider" tyres
HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)