ET: Engine (Twin) Stripped Splines on Kickstart Shaft and Lever (Weep)

[Robert Watson]

Early days on my first Rapide I stripped the splines. on shaft and lever, probably around the early '90's.
I set the shaft up , in those days no mill, so in the lathe, and indexed it in 6 places and ground 6 flats, measuring about .630 across the flats. Next I went down to the local tool supplier and bought a 5/8 AF deep impact type socket. I then drilled the lever out to the od of the socket. I may have turned the OD down a bit. Cut the socket length to the width of the lever. Put it all together. Fitted the socket in the lever, and put the lever on the shaft, and then positioned the shaft where I wanted it, and tack welded the lever and socket. Took it off and welded it up nicely and tidied up the weld. Next over to the band saw and split the socket to match the split in the lever. Just to be safe I drilled and tapped the end of the shaft for 1/4" bolt and made a nice big washer. Put it all together. Next time I had something being chromed it came off and was treated to new chrome.

It's been like that for some 25+ years, so like some of my other mods, not really proven yet,

Sounds more complicated to do that it actually was.

 

[Chris Launders]

One big twin that never had kickstart problems was Harley Davidson, they had a square on the end of the shaft, a practice I have adopted for worn Norton splines and I also have a modified Sturmey Archer shaft and HD kickstart on my 1150cc SS100 replica.
The HD shaft is a 0.600 square if it's any use

 

[stu spalding]

No splines but taper bolts acting on flats milled on the shaft. Some British gearboxes used same design, SA or Burman possibly.

The same system is used on MZs. If a bit of corrosion sets in it can be a dog to separate. Best to fit electric start. Cheers, Stu.

 

[Peter Holmes]

My uneducated guess is that a fine pitch spline was chosen because the kick start lever is probably the longest lever that you will find on any motorcycle, if they had gone coarse, one spline adjustment would have been a large movement at the business end. There were loads of crap spares floating around when all the factory spares ran dry, and everyone with a garden shed and a lathe started knocking out spares of dubious quality. I once purchased a slimmed down steel large idler with a central needle roller bearing, around the time when needle rollering the entire timing chest seemed like a good idea, when my engine eventually found its way to Tony Maughan he condemned it as total rubbish, badly manufactured, not treated correctly, and for stability reasons stated that the large idler should not run on needle rollers, a little off topic I know, but just to illustrate the point, only purchase top quality parts from people that know what they are doing.
If a kick start crank and shaft fail on the first few kicks, then clearly the fault lies with the quality of the parts, not the design of the original manufacturer, it would have been interesting to know how many cranks and shafts failed in the first 10 years from the original date of supply from the factory, very few I would suggest.

 

[ClassicBiker]

I suspect you are correct on both counts, Peter. Fine pitch on the spline and crap spares after the NOS were all gone. I particularly like Robert's solution. But would be worried today that I would only able to find rubbish impact sockets made of butter and nothing of higher quality. Still worth keeping that solution in mind though.
Steven

 

[Bill Thomas]

I bought a new stainless lever that was chromed, All the way from AUS,
A few Kicks and the chrome Split !,
Not Happy.
Don't know what I did with it, I think it's still flying through the air ?.

 

[vibrac]

Of course the effects of the 'empty years' of spares supply are still with us I have no doubt that Bob at Vincent spares often get complaints about the fit of his parts when the cause lies with the duff parts its being fitted to. Making parts in a shed without drawings and just one part to copy was all there was I suppose back then.
We all owe a lot to the club and the drawings project
fitting parts is a bit like relationships it takes two to tango.

 

[Graham Smith]

I bought a new Twin kickstart from Michael Breeding in USA.

It was top notch, and worked a treat with the slightly longer shaft that I got from the Spares Company.

The import duty would've been astronomical for the kickstart, but luckily I managed to use the VOC Courier Service to get it across the pond.

 

[ossie]

OK I concede, nothing lasts forever, not even cotter pins, but I purchased my Rapide in 1965 and it is still using the original Kickstart lever, so 57 years so far, and no sign of getting worn out yet, kick start spline sheering is not a regular topic of conversation on this Forum, so I would assume that I am not alone in finding the standard set up to be highly successful and reliable. Your solution is taken from the older cycle world, but no longer used there, apart from on the very cheapest cycles, we referred to them as cotter pins, and the nuts that held the cotter pin tight to the bottom bracket shaft needed to be checked and tightened frequently else they loosened and mangled the cotter pins and the pedal cranks came loose, in my opinion a ghastly solution to a problem that does not exist. It is of course essential that the male and female splines are a very close fit when the pinch bolt is loose, ideally requiring a firm push to engage the two, once that is achieved, and the pinch bolt tightened, the set up will last a very long time, for me 57 years and counting.
But if your starting point is a worn spline on both components, then no amount of tightening the pinch bolt will solve the problem.

when i bought mine in 66 it had a 1/4 bsf allen screw fitted 1/2 in shaft 1/2 in lever then tighten pinch bolt up, set lever in best position first.

 

[A Nut]

Another solution is to find a Burman kickstart which has the same spline (you can find them at autojumbles especially the fixed rather than the folding type) Cut the end off the Burman kickstart and also the damaged Vincent spline and weld them together using something like a Eutectic 680 rod. This needs doing properly, Welded right through not just tacked together. I have done quite a number of these without any problem. It can then be blended in and rechromed which is much cheaper than a new twin kickstart. You do, of course, need to buy a new kickstart shaft. This is also a mod for a folding kickstart on a Comet. Use you existing Comet spline and weld to something like a folding BSA or Triumph kiskstart
Brian