Author Topic: engine sprocket  (Read 861 times)

Offline worntorn

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 377
  • Karma: 3
Re: engine sprocket
« Reply #15 on: 12.09. 2018 14:43 »
Thanks Julian, I didn't know that about the RGS.
I guess the old way of looking at overall ratios is the least confusing when discussing gear ratios.
By my figuring, a 23 tooth engine with 46 tooth rear is identical to a 21 tooth engine and 42 tooth rear.
When you say the RGS had a lower geared gearbox, I assume you are referring to the first three gears only as top is 1 to 1?
Again, that is surprising, I would have guessed that the RGS had intermediate ratios more along the lines of the Goldstar close ratio type with very high first rather than ratios you might find on a sidecar tug.

The many and varied ratios of the BSA gearbox is a topic that I have barely scratched the surface of, not sure I'll ever dig into that one!
STB box on this late 63 SR.



Glen

Online JulianS

  • 1962 A10
  • Wise & Enlightened
  • *
  • Join Date: Mar 2017
  • Posts: 1009
  • Karma: 20
Re: engine sprocket
« Reply #16 on: 12.09. 2018 16:23 »
I meant lower gearing between gearbox and rear wheel, not refering to the intrernal ratios. Did not mean to confuse.

You may have seen the service sheets with gearbox markings and ratios, and the different designation used for boxes with the same ratios!

Online berger

  • Wise & Enlightened
  • *
  • Join Date: Nov 2017
  • Posts: 1149
  • Karma: 7
  • keith.chesterfield uk 500sscafe.norbsa project
Re: engine sprocket
« Reply #17 on: 12.09. 2018 18:46 »
worntorn well spotted its the bloody same except gearbox mainshaft is a bit slower and its corrected the speedo reading I hope

Offline baz

  • A's Best Friend
  • ***
  • Join Date: Apr 2012
  • Posts: 56
  • Karma: 2
Re: engine sprocket
« Reply #18 on: 12.09. 2018 22:36 »
i have a SR spec engine siamese exhaust goldie silencer and at the moment a 22 engine sprocket and a 42 tooth rear wheel sprocket and i have just changed to an 18" back wheel
from memory i think the gearbox sprocket is a 19 tooth sprocket, i  mostly ride  solo  it vibrates at 70 mph upwards i'd like to push that vibration up the range a little cheers

Offline worntorn

  • Valued Contributor
  • ****
  • Join Date: Jun 2015
  • Posts: 377
  • Karma: 3
Re: engine sprocket
« Reply #19 on: 13.09. 2018 01:08 »
Baz , that's very similar to my setup except I have 1 more tooth engine at 23.
Very comfy at 60 but even at just 65 the vibes get annoying after awhile.
I think my tolerance for vibration has diminished with age. No doubt the bikes I rode as a youth vibrated plenty, but I never noticed or cared.

Offline baz

  • A's Best Friend
  • ***
  • Join Date: Apr 2012
  • Posts: 56
  • Karma: 2
Re: engine sprocket
« Reply #20 on: 13.09. 2018 23:40 »
Baz , that's very similar to my setup except I have 1 more tooth engine at 23.
Very comfy at 60 but even at just 65 the vibes get annoying after awhile.
I think my tolerance for vibration has diminished with age. No doubt the bikes I rode as a youth vibrated plenty, but I never noticed or cared.
yep i know what you mean about being more tolerant to a bikes foibles in your youth
plus we didnt know any better!!!

Offline baz

  • A's Best Friend
  • ***
  • Join Date: Apr 2012
  • Posts: 56
  • Karma: 2
Re: engine sprocket
« Reply #21 on: 15.09. 2018 18:35 »
i fitted a 24 tooth engine sprocket and its fine for me riding solo and it does have an 18" back wheel which helps a little cheers