Comet Gearbox Noises

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youngjohn

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Just wondering if anyone can shed any light on a few issues with my Burman box on a Comet.

Changes are pretty good (including a nice silent snick into first and second), but changing up from second to third causes a small but noticable 'buzz' or 'graunch'. Third to fourth is fine. Changing down is all good except from second to first which can only be accomplished when you have practically stopped. Even walking pace will result in a 'graunch'.

The clutch is a Conways Honda and I'm pretty sure there's no drag. If there was, my experience is that neutral to first would be noisy. Changes are made nice and slowly. Primary chain is running in TQF as recommended by Conways and the box has the correct amount of Semi-Fluid Grease in it.

Also, I'm aware that the gearbox cases are different on the Comet, but are the internal gears etc. the same as AMC/Panther/Ariel?

Thanks for any help.
 
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cinquecento

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sounds like worn dogs to me. My Burman box can give little grumble when slipping into first, but having tweaked the clutch plates down a tad due to slipping i'm quite happy it's not dragging due to over adjustment.

given that finding neutral at lights is no problem i'm happy to live with a little wear after 60 years.
 
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tatty500

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Non-VOC Member
youngjohn,
I expect you've sorted this by now, but one thing that could cause your noise is excessive mainshaft end-float.
The mainshaft in a Burman can tolleate a lot of float. There are few detrimental effects of this.
One effect is on the clutch lifting action. When load is applied to lift the clutch this pushes the mainshaft towards the clutch end. This in itself probably won't matter, but what it does do is to allow the mainshaft third gear to move nearer the mainshaft sliding gear. This in turn could cause the third gear dogs to touch whilst the second gear dogs are still disengaging. creating the noise on this change.
So look in the cable access hole to see the the end flaot. More than 1mm is too much. A loose nut or warn sleeve in the starter gear/ratchet or a really bad bearing could be the reason.
Some time ago someone on the furum had so much end float that if the Comet in neatral was lent over to the primary side the third gear would fall onto its dogs on the sliding gear and be in gear.
But remember, what you read on the forum can be nothing to to with the actual problem!
Tatty500
 
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BigEd

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redbloke1956 said:
Eddy, this is only for the Primary chain case right??
Kev
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I don't think these light Automatic Transmission Fluids would stay in a Burman gearbox very long.;)
Quite a few people use ATF in their primary chain cases where the thin oil can more easily penetrate the bearing surfaces of the chain.
 
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BigEd

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Bill Thomas said:
I thought it was to make the Clutch work better, Cheers Bill.
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I don't know if it makes the clutch work better as the only bike I've had with a Burman clutch was an Ariel Square Four. This had the clutch outboard of the primary drive case in a nice dry compartment so the primary oil didn't come in contact with the friction material. I don't recall it slipping so it was a pretty good arrangement.:)
 
Bill Thomas

Bill Thomas

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Hello Eddy, John says he has the Honda clutch, And I have read that the twin multi clutches need a thin oil, All The Best, Bill.
 
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