Clutch push rod modification (for classic bikes)

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Dec 24, 2017, 10:00 AM
olderdan

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Clutch push rod modification (for classic bikes)

As anyone with a classic motorcycle knows achieving a smooth clutch action is difficult, this is not always due to the clutch itself even when set up correctly but more to do with the pushrod actuation.
The gearbox main shaft has a gun drilled bore which is left as a drilled finish, when pressure is applied to the ends of the push rod it will bend and rubs in the rough bore surface resulting in a sticky or jerky action, close inspection of a used one will confirm that this has been happening as there will be score marks on the rod.
Fortunately there is a simple remedy as written by Don Morley of trials fame in an article which can be found on Hitchcocks website. Hitchcocks Motorcycles - Technical Notes under article 5, the cut ends should be hardened and polished and as this is usually drill rod it is easily done.
I can testify that this mod makes an enormous difference to the feel of the clutch lever, the weight is still the same but the action is nicely smooth and I now do this mod on any classic that I work on.
Attachment 21046
Dec 25, 2017, 04:13 PM
KickStart

That's a cool website you shared.
I've used that trick at various times on different bikes. I have American V-Twins (60's-90's custom & stock) & British Twins (60's & 70's custom & stock, mostly Norton & Hybrid), and I like to mess with all of them. At one time I'd take on anything. The last time was a few years back when I built my high power rigid with a custom engine & drivetrain. The clutch pushrod was a custom length and needed some strong materials used. I used a through-hard core pin and ground matching recesses on the ends where the bearing balls fit, and obviously the balls were near the diameter of inside of the mainshaft. This kept the rods suspended and centered, and they were very rigid. I didn't use the whole end for contact, just a ring at whatever diameter I preferred. I don't recall what I did with the other ends, except that I would've ground them to whatever specific shape they needed to be, or improved them.
My wreck has slowed my action, but it's all still here waiting on me to get busy again. I was an accomplished toolmaker, so this was routine work then.
Dec 27, 2017, 08:04 PM
DIYer


Thanks olderdan! We've added your Clutch Push Rod Modification to our Motorcycle category,
as well as to your builder page: olderdan's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-clutch-push-rod-modification"> <img src="/uploads/208382/homemade-clutch-push-rod-modification.png"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-clutch-push-rod-modification">Clutch Push Rod Modification</a> <span> by <a href="http://www.homemadetools.net/builder/olderdan">olderdan</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/motorcycle'>motorcycle</a>, <a href='http://www.homemadetools.net/tag/clutch'>clutch</a> </div> </div> </div> </div>