Author Topic: Kickstart Mechanism Mark Series gearbox  (Read 3305 times)

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Offline Reg

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Kickstart Mechanism Mark Series gearbox
« on: 11 Apr 2016 at 08:50 »
Is there a modern 'O'ring alternative to the felt washer (Part No. 35548/Item 19/Plate 18) for the kickstart spindle. If so, are they rubber or nitrile and where do you source them? The groove in the kickstart bush is 1/8" wide with diameter of 0.095" taking the spindle diameter of 0.750"
Reg

Offline Reg

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Re: Kickstart Mechanism Mark Series gearbox
« Reply #1 on: 11 Apr 2016 at 13:25 »
Sorry, my mistake. Groove o/s diameter should be 0.950"
Reg

Online Doug

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Re: Kickstart Mechanism Mark Series gearbox
« Reply #2 on: 11 Apr 2016 at 16:12 »
Reg,

No direct replacement. Standard o-rings have equal width and annular gap. So while a -116 o-ring would be 3/4 i.d. and 15/16 o.d. (0.728 i.d., 0.943 o.d. and 0.103 width actual), the width would be only 3/32 inch. Step up to a 1/8 inch section o-ring (-210; 0.139 width actual) and the section is too big to fit the existing o.d. You can get the same o-ring in round, double seal (x-cross section) and multi-seal (eight point start section), but they all follow the same shaft/bore/width conventions.

The -116 o-ring would stretch a little on the 3/4 inch shaft and probably take up slight gap at the o.d., but it is still a little narrow in the existing groove. It might work though, and cannot be any worse than a worn felt! Problem is it is a lot of bother to strip the case down to that point, so you only want to do it once.

-Doug

-Doug
« Last Edit: 12 Apr 2016 at 13:34 by Doug »

Offline chris mac

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Re: Kickstart Mechanism Mark Series gearbox
« Reply #3 on: 12 Apr 2016 at 05:34 »
I routinely make O rings in whatever thickness and diameter I need, although usually bigger than 1" od .  Go to your local Bearing House and ask for  the O ring making kit
Best.  Chris Mac

Offline Reg

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Re: Kickstart Mechanism Mark Series gearbox
« Reply #4 on: 14 Apr 2016 at 09:54 »
Doug/Chris Mac,
Many thanks for the response.
Reg.