primary casing alloy

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trevair
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Location: LANCASHIRE UK

primary casing alloy

Post by trevair »

hi all
i have a 1955 g80s i would like to change the tin can primary casing for an alloy one mine is the one with the spring shock absorber on the crank is there one off another model which will fit my bike.
also i have rebuilt the engine with new parts etc i have started the bike runs perfect oil returned to tank etc when i have left the bike standing for 3 weeks in side stand dont have centre as i have changed it to a trails model if i kick over before starting oil comes out of the breather tube left hand crankcase cant understand as it doesent seem to be wet sumping from tank
any help would be appreciated
regards trev
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dave16mct
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Re: primary casing alloy

Post by dave16mct »

There isn't an alloy chaincase which will easily fit. Also you will have no provision for the dynamo. You could put your bike on a paddock stand (I've got one if you want it) , axle stands or lean against a wall. Also always turn it over onto compression when you leave it. Most of the time it puts the oilpump plunger in the right position to stop leakage down to the crankcase. (Not always!)
Cheers Dave.
trevair
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Location: LANCASHIRE UK

Re: primary casing alloy

Post by trevair »

MATCHLESS 1.jpg
hi dave im not using a dynamo as its a trails conversion dont know if im keeping it though
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Pharisee
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Re: primary casing alloy

Post by Pharisee »

The later engines that were fitted with an alloy chaincase also had the 'cush drive' in the clutch so the chaincase would not fit onto an engine with the big spring and cams on the the drive side crankshaft axle. You would potentially have to fit the later crankshaft axle and an AMC clutch.
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39speedtwin
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Re: primary casing alloy

Post by 39speedtwin »

Look out for one of the Italian made alloy cases, which were made in the late 1940's early 50's to replace the tin cases on singles.
They do turn up from time to time at autojumbles, these accommodate the Cush drive.
JEAN-NOEL
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Re: primary casing alloy

Post by JEAN-NOEL »

The alloy chaincase for alternator bikes does not let enough room for the cushdrive ? Just a thought...
Mick D
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Re: primary casing alloy

Post by Mick D »

Hi

Didn't some of the later twins have alloy cases and spring shock absorber - could a pair of those be adapted?

Regards Mick
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dave16mct
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Re: primary casing alloy

Post by dave16mct »

No it was in the clutch and also some in the back wheel hub.
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