Author Topic: DRAGONFLY FINAL DRIVE  (Read 1730 times)

0 Members and 1 Guest are viewing this topic.

Offline steve.link

  • Member
  • *
  • Join Date: Sep 2017
  • Posts: 8
  • Location: cardiff
DRAGONFLY FINAL DRIVE
« on: 13 Oct 2019 at 21:49 »
Hi,

Anyone know how much backlash is permitted on the final drive bevel gears. With first gear engaged and the input shaft held stationary I can move the final drive sprocket about 3/16 inch - is this OK?
Also how may shims are needed between the sprocket housing and gearbox casing.

Thanks

Steve

Offline steve.link

  • Member
  • *
  • Join Date: Sep 2017
  • Posts: 8
  • Location: cardiff
Re: DRAGONFLY FINAL DRIVE
« Reply #1 on: 22 Oct 2019 at 16:03 »
Anybody able to help with this?

Offline eddie

  • Master Member
  • ****
  • Join Date: Mar 2006
  • Posts: 1431
  • Location: Hampshire, UK
Re: DRAGONFLY FINAL DRIVE
« Reply #2 on: 22 Oct 2019 at 17:49 »
Hi Steve,
               I would think the 3/16" of movement you have is about right. Remember, when you hold the input shaft and rock the final drive, you are not only seeing the backlash in the final drive but also the backlash in the main shaft dogs - they have to have enough clearance to enable easy gear changing.
  Regarding the number of shims behind the final drive - I have never seen any official method of adjusting the mesh of the bevel gears, so can't advise on how many shims should be fitted. Normally those gears whine with the power on when they are meshed too tight, or whine on the overrun when too slack. Having said that, if the gears have run for some time with incorrect adjustment, they may have developed a wear pattern that then makes silent running almost impossible. When I rebuild a gearbox, I just rebuild with the same number of shims and accept that as good enough.

   Regards,
                  Eddie.

Offline Neville Heath

  • Full Member
  • **
  • Join Date: Aug 2013
  • Posts: 38
  • Location: Ipswich
Re: DRAGONFLY FINAL DRIVE
« Reply #3 on: 23 Oct 2019 at 10:08 »
There is advice on how to do this in my Spannerama book
Neville

Offline steve.link

  • Member
  • *
  • Join Date: Sep 2017
  • Posts: 8
  • Location: cardiff
Re: DRAGONFLY FINAL DRIVE
« Reply #4 on: 23 Oct 2019 at 16:07 »
There is advice on how to do this in my Spannerama book
Neville

Neville

Thanks - where can I buy a book?

Offline steve.link

  • Member
  • *
  • Join Date: Sep 2017
  • Posts: 8
  • Location: cardiff
Re: DRAGONFLY FINAL DRIVE
« Reply #5 on: 23 Oct 2019 at 16:10 »
Eddie,

Thanks for the advice - I have built this from bits and pieces so don't know how many shims were on in the first place. I have used 2 and it does seem ok to me but never done one before. I will check out Neville's book

Thanks


[fix formatting. 23Oct19 -Doug, Site Moderator]
« Last Edit: 23 Oct 2019 at 18:19 by Doug »

Offline Neville Heath

  • Full Member
  • **
  • Join Date: Aug 2013
  • Posts: 38
  • Location: Ipswich
Re: DRAGONFLY FINAL DRIVE
« Reply #6 on: 25 Oct 2019 at 15:18 »
Steve
  I wrote"Spannerama" many years ago, and how to obtain it is always advertised in the L.D.C. magazine "The New Conrod". It is available to all Club members and costs 7 (including postage) which is donated to charity. There are 32 pages of information based on my experience of post war models that is not to be found in the manufacturers manual. For instance, I noticed a few months ago on the forum that a Douglas owner had suffered a dipstick falling into the gearbox with nasty results. There is mention of that fault in the book. 
  Neville

Offline steve.link

  • Member
  • *
  • Join Date: Sep 2017
  • Posts: 8
  • Location: cardiff
Re: DRAGONFLY FINAL DRIVE
« Reply #7 on: 26 Oct 2019 at 23:15 »
Steve
  I wrote"Spannerama" many years ago, and how to obtain it is always advertised in the L.D.C. magazine "The New Conrod". It is available to all Club members and costs 7 (including postage) which is donated to charity. There are 32 pages of information based on my experience of post war models that is not to be found in the manufacturers manual. For instance, I noticed a few months ago on the forum that a Douglas owner had suffered a dipstick falling into the gearbox with nasty results. There is mention of that fault in the book. 
  Neville

Thanks for the info!

 

motorcycle