Lightweight Gearbox

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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shifter
Posts: 479
Joined: Mon Jun 16, 2014 8:30 pm
Location: NORTH

Lightweight Gearbox

Post by shifter »

There is a gear box on the old bay for sale I think the price wanted is a little optimistic? eBay item number:
401472924246
?
geoffb-63
Posts: 41
Joined: Sun Oct 01, 2017 4:49 pm
Location: Cleveland, UK.

Re: Lightweight Gearbox

Post by geoffb-63 »

Was starting bid £150 last week, didn`t sell, so he`s re advertised at a higher price this week.
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Ozmadman
Posts: 2651
Joined: Wed Dec 14, 2011 1:02 am
Location: ESSEX UK

Re: Lightweight Gearbox

Post by Ozmadman »

Yes well overpriced, especially as it is an early box with that gearbox number. It will have the old peg type sliding gear and sleeve gear which caused the top gear to disengage if worn

"Top gear disengages. This is most likely to occur on early
type gear boxes before 7988 (250 cc.) and 2300 (350 cc)."

Plus

"First gear modification. In gear boxes made before number
G8603 (250 cc. Model) and M2701 (350 cc. Model) a plain
layshaft first gear 041291 was used. This is superseded by a
bushed pinion 044080. The new first gear can be used with the
existing second gear pinion

Plus

Wear on kickstarter axle bush. Only likely to occur on
early models with gear box numbers before G6014. This can
happen if the kickstarter return spring 040043 is overwound,
which tends to pre-load the kickstarter bush against the
first gear pinion. Gear boxes after the above number are
fitted with a circlip 042900 encircling the kickstarter axle
042130 with a thrust washer 042901 to prevent pre-loading also
wear on the axle bush. The new parts can be fitted to earlier

Plus

250 cc. Lightweight. Mainshaft 041263 is used on gear
boxes from zero to 9974, also to gear boxes between numbers
10064 to 10128 as a temporary measure.
A modified shaft type 043058 is used in gear boxes with
numbers 9975 to 10063 inclusive, which is now the current
type.

Of course these mods may have already been done over the course of time but you won't know that until you have bought the box
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
shifter
Posts: 479
Joined: Mon Jun 16, 2014 8:30 pm
Location: NORTH

Re: Lightweight Gearbox

Post by shifter »

Paul
Thank you for all the above information in layman's terms very handy to keep, as for the gearbox I don't think he will get what he wants for it. I had a snoop through e bay's past dealings on lightweight gearbox's and he had it up for sale @ £150 last year the mind boggles
shifter
?
Reynard24
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Posts: 362
Joined: Mon Dec 16, 2013 2:27 pm
Location: CAMBRIDGESHIRE UK

Re: Lightweight Gearbox

Post by Reynard24 »

Funny how things change, I had a complete lightweight gear box and the best part of another and had real trouble even giving them away at the Kimbolton Jampot rally in 2009.
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Ozmadman
Posts: 2651
Joined: Wed Dec 14, 2011 1:02 am
Location: ESSEX UK

Re: Lightweight Gearbox

Post by Ozmadman »

I have two spare boxes (one is now on the bike after a rebuild so have the original as a spare ) and didn't pay more than £60 for either of them
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
alanengineer
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Joined: Wed Oct 12, 2005 10:45 pm
Location: KENT UK

Re: Lightweight Gearbox

Post by alanengineer »

I think anybody who has rebuilt a lightweight has collectected gearbox spares for them. i think i still have 2 gearboxes in bits including the later modified sleeve gear.
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