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Tiger Cub Modified Gearbox Cover


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On 28/01/2018 at 3:28 PM, thai-ty said:

Lovely job. Nice interesting read and great photos.

Shorten the gear lever split clamp allen head so no thread is protruding.

Replace the 3 'orrible c'sunk crossheads with c'sunk allens.

Sorry for being pedantic....


I ran the bike for around 15mins outside my house and no signs of any oil leaks so far.  Fingers crossed??


Armac gearbox case finished 1.JPG

Armac gearbox case finished.JPG

Edited by brucey
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  • 1 month later...

I've been preparing my spare Cub for my Son to ride in some Pre 65 trials with me.  Since I now have a spare gearbox cover from my Armac Cub, I decided to upgrade my old Cub and fit a clutch lightener, blind cam bush, gear selector oil seal and kick start shaft oil seal. 

As this bike is running standard road gearing I will also be fitting a 16T primary gear to get 1st and 2nd lower.  This bike is running with standard type clutch but with ally end plate and an additional friction plate.

Unlike my Armac cover, I had the kick start shaft housing welded where the flat is in this one to prevent the od 28, id 22 x 4 seal breaking through.  Bear in mind you still need to be able to get the selector plate pivot pin in and out!

I have added some photos as I know some other people were considering this modification.  I think I should have taken my own advice and machined the seal recess 4.5mm to 5mm deep instead of 4mm, but I'll see how it goes together! 

As not everyone has a mill in their shed, I'm assuming someone like UPB can do all this machining for you.

I hope this helps someone.  Enjoy :-)


std mod gearcase 2.JPG

std mod gearcase weld.JPG

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