Author Topic: How to fit gearbox/engine cases into the frame?  (Read 177 times)

Online Nourish

  • A's Good Friend
  • ***
  • Join Date: Aug 2013
  • Posts: 249
  • Karma: 1
So how do you fit the gearbox crankcase assembly and plates into the frame without scratching the paint?
Long stroke A7

Online jhg1958

  • Valued Contributor
  • ****
  • Join Date: Sep 2019
  • Posts: 369
  • Karma: 7
  • The more I learn I realise how little I know
Re: How to fit gearbox/engine cases into the frame?
« Reply #1 on: 15.06. 2026 20:13 »
I suspect most sensible people put the cylinder and head on in situ or at least get the help of a friend or two.  I put the engine on its left hand side and lowered the frame on top of it.  Bolted it in whilst it was on its side and lifted engine and frame. Gearbox was later. I managed it on my own without any problems.

John
1961 Golden Flash S/Arm

Online Swarfcut

  • Wise & Enlightened
  • *
  • Join Date: Oct 2018
  • Posts: 2708
  • Karma: 58
Re: How to fit gearbox/engine cases into the frame?
« Reply #2 on: 15.06. 2026 20:29 »
Simple answer is don't attempt to install a fully built engine. Gearbox and crankcase as a unit is the way to go, but lowering the frame with the engine on its side won't work with the bolt on gearbox which must be attached at the start. Conside how you will do it, along with thoughtful preparation. Masking tape and padding on frame tubes, nuts and bolts to hand, threads nice and clean, ready to go.  Support blocks, gloves, beer.......
 The dynamo strap lower pivot pin and right side front mounting plate have to go on in a certain order on the Long Stroke engine. From memory the pin passes through the mounting plate so can only be fitted after the plate is in place, so leaving the inner timing cover off until the crankcase and gearbox are mounted makes life easier. Also the inner cover will not pass over the ATD unit.
  Does your frame have a factory brazed on side stand lug? Thought those were only from '53 onwards.

 Folks manage assembly single handed, but an extra pair of hands certainly helps, and it is a case of lowering and twisting the unit into place, ever watchful for unwanted points of contact.

 Swarfy.

Online Nourish

  • A's Good Friend
  • ***
  • Join Date: Aug 2013
  • Posts: 249
  • Karma: 1
Re: How to fit gearbox/engine cases into the frame?
« Reply #3 on: 15.06. 2026 23:10 »
Well spotted - the side stand lug is my addition.
Long stroke A7

Online Swarfcut

  • Wise & Enlightened
  • *
  • Join Date: Oct 2018
  • Posts: 2708
  • Karma: 58
Re: How to fit gearbox/engine cases into the frame?
« Reply #4 on: 16.06. 2026 06:37 »
 I did wonder if the frame was original, as with the introduction of the Plunger Frame, the rigid version changed to  a two piece and used a common bolt on front section ......so a later type front could be fitted to an earlier rigid rear. Your frame looks like a one piece, almost a custom style and the side stand lug looks like a factory type which didn't ring true for the year.

Swarfy.

Online Roger (Doomtrainbarx)

  • Valued Contributor
  • ****
  • Join Date: Jun 2020
  • Posts: 276
  • Karma: 1
    • Soundclick
Re: How to fit gearbox/engine cases into the frame?
« Reply #5 on: 16.06. 2026 09:52 »
I fitted my engine complete, with gearbox and mounting plates already installed.
I did it with the dynamo and front engine plates removed - went in quite easy - I put a suitable sized wooden block in place ready to sit the engine on the sump plate while I jiggled the bolts in - simple !!
1962 Super Rocket
1989 Harley FXRS (Turbo)

Online Nourish

  • A's Good Friend
  • ***
  • Join Date: Aug 2013
  • Posts: 249
  • Karma: 1
Re: How to fit gearbox/engine cases into the frame?
« Reply #6 on: 16.06. 2026 20:52 »
I presume Roger that your's isn't a long stroke?
Long stroke A7