Boxerworks.com

I put this little mod together after seeing something similar posted by Rob Frankham on the BM Bikes forum. It halves the effort required from my poor old left hand and should make clutch operation significantly smoother. It is particularly suited for the pre '81 bikes, which have a notoriously heavy clutch with a quite abrupt engagement.

Apparently the idea has been around for a long time. There's a kit available from Craig Vechorik at Bench Mark Works that uses a chain and pulley:
http://www.benchmarkworks.com/articles/ ... lutch.html
I gather these work very well but fitment involves cutting the clutch cable. The arrangement I'm using can be fitted in a few minutes with no modification to OE parts.
There are a lot of different ways to skin this cat. Mine uses a genuine crusty old rear wheel spoke as the connecting rod, shortened by 70mm and threaded M4. The sheave is printed ABS, 32mm OD with a pressed in aluminium bush. The frame and fixing bracket are fabricated from 1.2mm stainless sheet. The extra nipple was saved from a dead clutch cable, or can be easily cut from 8mm aluminium rod as shown in the above pic. Incidentally, in use the pulley sheave rotates back and forth through ~30 degrees.

The end result is that I can squeeze the clutch lever to the bar between thumb and forefinger. I had already fitted the lighter clutch diaphragm spring as sold by Motobins about 10 years ago. I haven't had the opportunity to use the mod in anger, since the old dear is having some shed time at the moment. Static testing with the bike in gear confirms that the clutch engages and disengages as it should.

Nice job!!!

Tom

Thanks for the acknowledgment...

Rob

Nice work!

Here's a link to the original thread on the BM Bikes forum which includes my version of the clutch mechanism for comparison.

https://www.bmbikes.org.uk/viewtopic.ph ... lit=clutch

Rob

That was impressive, though so long as I can pull the clutch on my '70 Bonneville nothing on my R65 will need to be changes.

Another version, apparently a commercially available option from the olden daze:

Installed the EZclutch mod that I put together on my bike today, sure made a difference, now the clutch can pull with a finger.

Well done, Gerard.

I've just arrived home from riding 1300kms in the last 3 days on B, C and probably D roads through rural New South Wales. Many hundreds of gear changes and not a single cramp in my left hand. The cramping was threatening to put a stop to my riding but this mod has made all the difference.

Appreciation attached for Rob Frankham for posting his simple, elegant design, assembled entirely from 'found' objects, on the BM Bikes forum.

Airbear wrote: ↑Sun Mar 13, 2022 4:59 am Well done, Gerard.

I've just arrived home from riding 1300kms in the last 3 days on B, C and probably D roads through rural New South Wales. Many hundreds of gear changes and not a single cramp in my left hand. The cramping was threatening to put a stop to my riding but this mod has made all the difference.

Appreciation attached for Rob Frankham for posting his simple, elegant design, assembled entirely from 'found' objects, on the BM Bikes forum.

Thank you I really appreciate the feedback, it's good to know you've benefitted from it. Of course, it wasn't a new idea, just my take on it...

Currently I'm sitting at home on day two of a ten day Covid self isolation, having tested positive yesterday, looking out of the window at slashing rain and wondering whether I'll ever get out on a bike again so your post has cleared a bit of the depression.

Rob