splines

derek

Well Known and Active Forum User
VOC Member
How are splines measured? How are the kick start and gear change splines on a Comet defined?
 

roy the mechanic

Well Known and Active Forum User
VOC Member
splines usually reffered to as diameter x number of peaks. example- jaguar clutch centre spline = one and an eighth inch x ten , when i had my twin starter shaft modified to take an alternative kicker lever the machinist involved said "this is not a spline- it's actually a knurl, " measured in the same manner.i figure he knew, best of all the new arm fits like"the paper on the wall! i cant comment on actual size as i have no reference to burman bits.
 

John Cone

Well Known and Active Forum User
VOC Member
The markings on a kick start shaft are niether knurlings nor splines, they are serations. Knurling is used to increase the diameter of a shaft that is worn and give a crisscross effect on the steel and is ideal when you have a bearing that is slack on the shaft. Splines are used in things such as gearboxes or differentials where a gear is required to slided to and fro along a shaft. Serations merely hold things in place to stop slipage. Thats what I was taught at college many years ago but like everything else things do change.
 

clevtrev

Well Known and Active Forum User
VOC Member
Your Burman shaft splines are cut on a milling machine. The selection of 40 teeth is simple, because a dividing head, used in those days, needed 40 turns of the operating handle to rotate through one revolution. Different ways of doing this milling, depended on the operators preference. That operator had to be by , and turn the handle after every single cut.
The ones I make today are generated with a controlled head. So I have the luxury of walking away until the job is complete.
 

derek

Well Known and Active Forum User
VOC Member
The reason that I asked the question, is that I wish to obtain a replacement kick start lever, longer and fold away. I think that the Indian Royal Enfield may suit. Knurling a shaft to increase diameter is not a good idea and will not last, it is beter to use locktight or do the job properly.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Hello Derek, Somebody told me, Sammy Miller does them, Not sure who, Might be worth a ring at the Museum,01425620777 Cheers Bill.
 

Comet Rider

Well Known and Active Forum User
VOC Member
Hi Bill,
Yes Sammy Miller does 2 types of replacement kickstarts levers.
The only difference being that they fold at the bottom, rather than the top, are slightly longer than standard (about an 1" or so).
The difference between the two offerings isthe offset to clear the exhaust.

Works well

Neil
 

tonythecat

Well Known and Active Forum User
Non-VOC Member
Hi Derek,

I have made 2 of these longer, fold-away kick start shafts, both from Yamaha 750 stock ( cheap at autojumble), I don't know what the exact model years they were from but the first one was too large in the splined hole so used a burman spline off an old kicker and welded it to the Yam. The next one I found (this time I had a vernier with me!!!) was too small in the hole so had the splined part enlarged. Works great extra inch or so gives more power to the kick, and folds away.
Tony
 
Top