The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Ron B on 10.04. 2011 13:50

Title: Gearbox removal 49 A7 Long Stroke
Post by: Ron B on 10.04. 2011 13:50

Hello everyone, I am new to this forum and need some advice and information.  I need to remove the gearbox.  Is it possible to just tip the engine forward on the bottom front bolt to remove the gearbox or do I need to pull the entire engine out.  Thanks

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: muskrat on 10.04. 2011 14:07

G'day Ron, welcome to the forum.
                                              I needed to ask that very question about 30 years ago, but there was no forum back then.
Took me two days to get it out with the motor still in the frame. It only takes two hours to take the whole lump out now, and then 10 minutes to drop the box off. Two man job to do it safely (no damage to bike or fingers).
Cheers

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: fido on 10.04. 2011 15:57

Welcome to the forum, Ron. We seem to be getting quite a few people with longstroke A7s these days. I've had my '48 machine for some years but not yet had it to bits. My 'box is noisy though so a must open it up some time.

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: beezalex on 11.04. 2011 15:14

As muskrat sez, to pull the box off the motor, you're really just going to make yourself miserable trying to do it with the engine in the frame.  That said, the only reason I can see for removing the gearbox cases is if they need welding, otherwise, you can do just about anything to the box with the case still on the motor.

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: wilko on 11.04. 2011 20:21

My thoughts too. When you can do everything insitu. Removing bearings with the help of propane or heatgun.

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: bsarider on 05.05. 2011 19:18

I have just tried to prove you can get the box off without removing the engine and failed.I had to remove the engine and box complete because the fixing studs between box and engine  stop you pulling the box sideways and the top lug also stops you pulling the box out.Take all the bolts out and jack the engine out of the frame then a two man team can easily lift out the unit.I only wanted the gearbox output bearing and seal changing to stop it leaking and found that there isnt a seal only a steel lip and a thrower groove on the sprocket.Spoke to Paul at JB Restorations and he says the new seal will work with a smooth outer race to the 18T final drive sprocket so that is what I am doing at the present , changing the pulley and throwing the old one away.Alan

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: wilko on 05.05. 2011 22:39

Still can't see why you had to take the box out? Have i missed something?

Title: Re: Gearbox removal 49 A7 Long Stroke
Post by: trevinoz on 05.05. 2011 22:50

Wilko,
             It is a plunger engine/gearbox and the main bearing and seal cannot be accessed with the box bolted on.
  Trev.