Noisey in second and third gear

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Noisey in second and third gear

Postby willowbedone » Sat May 18, 2019 6:39 pm

The gear box on my g80 is whining in second and third gear If anyone has any idea will it be bearings thurst washers ? Or gears worn out
ANY ADVISE PLEASE
IAN

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Re: Noisey in second and third gear

Postby oldandsmelly » Sat May 18, 2019 6:51 pm

Which gearbox is it... Burman CP, B52 or AMC? If you're unsure, a photo or description of what the outer cover looks like would help. Selective whining gears are usually poor gear teeth contact, either slightly offset or too tightly meshed. If it is worrying, the best idea would be to strip the box and have a looksee. This may sound scary, but the Burman boxes are actually very straightforward with little scope for cock up; I find AMC boxes one level up in difficulty but still not too hard if you are methodical.

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Re: Noisey in second and third gear

Postby Greybeard » Sat May 18, 2019 7:12 pm

I had a similar problem with a Burman BAP box on my '36/7 Sunbeam Lion. I eventually identified the cause as worn tooth surfaces probably as a result of it being run with very worn layshaft bushes allowing the gears to rattle around and fret..
You may be lucky and find that new layshaft bushes cure, or at least reduce it. If not be prepared to track down replacement gears. There are some nasty pics here of the damage you might find with a magnifying glass.

https://www.marston-sunbeam.org/sunbeam ... 63#msg1063

Burman gears are not case hardened so replacements can be cut by a competent engineering company at a more reasonable cost, though i found new replacements via the Vincent OC (same gearbox) along with good used parts. It cost a good few hundred quid and a lengthy search by the time Id sorted it.

Good luck. Steve

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