Leaky GB gearbox

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Paul_Linden
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Leaky GB gearbox

Postby Paul_Linden » Sat Nov 21, 2020 1:04 pm

I’m slowly fixing the small issues on my bike, but can’t seem to resolve a small oil leak from the gear lever shaft on my GB7 gearbox. The bush and seal have been replaced, and the shaft is smooth, clean and doesn’t wobble, but it still dribbles after a few minutes on the road. It doesn’t leak when the bike is parked.
The GB7 box on my other Ariel doesn’t do this. Is this fixable, or just something to live with?
I’ve got a spare cover, so I’m willing to try putting a ‘proper’ oil seal in rather than the rubber ring that Burman specified.
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

john.whiting
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Re: Leaky GB gearbox

Postby john.whiting » Sun Nov 22, 2020 11:51 am

Possibly the rubber O ring has been shaved when assembling the case over the shaft.

JohnnyBeckett
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Re: Leaky GB gearbox

Postby JohnnyBeckett » Sun Nov 22, 2020 3:30 pm

hi the rubber o ring may not be the right one i have had this with o rings because a lot of o rings they give you are metric and they do not fit right i would see how it fits on the shaft and how it fits in the case and i put a little chamfer on the shaft to help it slide on and i put silicone on the o ring and shaft and it just slides on :?: PS if you do not have silicone use pledge furniture polish spray its got lots of silicone in it

RalphM
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Re: Leaky GB gearbox

Postby RalphM » Sun Nov 22, 2020 4:10 pm

Cut the finger off one of those thin plastic gloves or use a part of a thin plastic bag
put it over the shaft and slide the o'ring/seal over it, you can then gently pull the bag
out from under the seal/o'ring with the case fitted.
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Paul_Linden
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Re: Leaky GB gearbox

Postby Paul_Linden » Tue Nov 24, 2020 4:37 pm

It is the correct seal, as it is a rubber collar with a chamfered edge, not an O ring, and it fits exactly in to a recess in the metal holder that is pressed in to the outer case.
It doesn’t catch when sliding the gear shaft through it.
So I’m still stumped on this.
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

RalphM
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Re: Leaky GB gearbox

Postby RalphM » Tue Nov 24, 2020 5:29 pm

Is it leaking round the outside of the seal rather than along the shaft?
if so a smear of sealant round the seal before fitting it to the box.
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Paul_Linden
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Re: Leaky GB gearbox

Postby Paul_Linden » Thu Nov 26, 2020 6:23 pm

So it turns out that the new seals I bought are too slack and allow the oil to escape.
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......


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