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Gear box oil leak

Submitted by geoff_hastings on Mon, 29/07/2024
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I have a 1957 international and getting ready for its first start in 40 years. I've topped up all the oil levels and now find there is an oil leak from the bolt that retains the gear change cam as it moves when I operate the gear lever,I believe there is an o-ring on the bolt. My question is, can I remove the bolt and change the o-ring without the cam assembly falling into the gearbox?

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Submitted by peter_shand on Mon, 29/07/2024

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You might find that it doesn't have an O ring. I know a 1956 ES2 with a laydown box doesn't have one, i had to machine the case to accept the later O ring

Submitted by geoff_hastings on Tue, 30/07/2024

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Hi guys, I removed the bolt and sure enough there is no o-ring fitted. As the gearbox is in the bike and I've only just assembled the bike the prospect of removing it didn't really appeal. I ended up machining a small groove into the bolt just by the hex head and fitted my own o-ring. Obviously this will weaken the bolt and I would have preferred to fit the o-ring into the casing but we'll see if this holds up. It has cured the leak though.

Submitted by jonathan_newton on Tue, 30/07/2024

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I thought there was a cork washer inset there. Be careful the bolt locks in;  with (maybe) a cork and an "O"ring you may not get the bolt to hold.  I would recommend a "Dowty" washer.
But if it's cured, fine, just keep an eye on the bolt.
 

Hi Jonathon, I'm not sure what you mean by "the bolt locks in" When I removed the bolt it only had a plain flat washer and just unscrewed as you'd expect a bolt to do. The bolt head does rotate as the cam rotates so a cork washer might stop the cam rotating and so prevent gear selection.

Submitted by jonathan_newton on Sun, 04/08/2024

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In my memory there was a cork washer there. The bolts tightened up on a flat washer and bottomed out in the cam wheel shaft. The washer pressured the cork to expand and seal. The bolt was locked by being bottomed.  Maybe it was a modification by previous owner ?

 



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