Mk3 backfire device

Joined
Jul 3, 2009
Messages
789
Country flag
Hi there, I am in the process of completing the rebuild on a Mk3 that came to me in pieces and I do not know the history of, as I am completing the assembly of the primary a friend suggested that I check the torque on the backfire gear, from what I understand to do this I would have to buy/ build a socket adaptor that would enable the torque wrench to be mounted on the splined shaft and the cost appears to be considerable, is it common for the backfire gear not to be at the correct torque setting?
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,085
Country flag
from what I understand to do this I would have to buy/ build a socket adaptor that would enable the torque wrench to be mounted on the splined shaft and the cost appears to be considerable,

I used short lengths of welding rod inserted between the splines and a suitably sized socket.

is it common for the backfire gear not to be at the correct torque setting?

It's worth checking if you are able to, in my opinion.
 

Mart UK

VIP MEMBER
Joined
Mar 11, 2021
Messages
351
Country flag
Hi,

Look at this Old Brits article:
"Another way to adjust this device which I have not tried, but a couple of customers have tried successfully, is to slowly back off the nut and hit the starter until the device slips and will not turn over the engine. Then tighten the nut until it will just turn over the engine. Again I think you will need to mark the nut in case it backs off when the device slips."

When I replaced my sprag, bearings, washer, chain, clutch hub etc., I left the backfire overload device well alone. It didn't look like it had been mangled by wrenches / spanners, so I trusted it.
 
Top