Jammed oil pump

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
Red Gauntlet
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Jammed oil pump

Post by Red Gauntlet »

Ok so I have a G5 with a jammed oil pump, it rotates but very tight, the case is cracked at the front of the engine where the pump has been attempted to be removed so drilling a hole and drifting the pump out is not such a heart ache, unless anyone has better ideas on pump removal, it is a pity that they never put a thread in the pump to draw it out, the timing side bushing is loose too, maybe part of the failure or just a coincidence, sadly the crank has shifted over to the drive side and the casing around the top of the mains is cracked as well. I would ideally like to acquire a set of good 61/G5 cases but maybe I am wishing into the wind on this idea...
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clive
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Re: Jammed oil pump

Post by clive »

sounds like a major repair job, probably good you have use the advertising forum pages and the adverts to ask for the new parts. hope you are successful.
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clanger9
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Re: Jammed oil pump

Post by clanger9 »

Ouch. You'll need replacement cases, as a minimum. They do come up for sale occasionally.
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Red Gauntlet
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Re: Jammed oil pump

Post by Red Gauntlet »

Will G2 cases fit the G5 bits I wonder?
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clanger9
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Re: Jammed oil pump

Post by clanger9 »

I think the late CSR and G5 cases are the same. G2 (and very early G5) have the "short" oil filter.
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Re: Jammed oil pump

Post by SPRIDDLER »

Mighty Max wrote:Will G2 cases fit the G5 bits I wonder?
IKBA about L/Ws and your Profile doesn't show what year is yours (if it matters) but in the spares list the c/case halves for the G2 have different part nos from those for the G5.............

http://archives.jampot.dk/book/Spares_l ... s_List.pdf
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clanger9
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Re: Jammed oil pump

Post by clanger9 »

The problem is the spares lists are only accurate for early Lightweights. Later on, it all seemed to fall apart and AMC didn't bother to keep track of all the changes...
The late CSRs used a number of "uprated" bits from the G5.
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Re: Jammed oil pump

Post by SPRIDDLER »

clanger9 wrote:The problem is the spares lists are only accurate for early Lightweights. Later on, it all seemed to fall apart and AMC didn't bother to keep track of all the changes...
The late CSRs used a number of "uprated" bits from the G5.
Ta. Interesting. I'd missed Max's mention that his is a '61.

Idle thought: I wonder whether the G5 cylinder would fit on a G2 c/case even though the G5's bore diameter is only 2.15mm greater than the G2 as I've never heard of anyone uprating their G2 to a 350cc G5 by fitting the G5 cylinder etc. as folk have done on the H/W models............... :?
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clanger9
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Re: Jammed oil pump

Post by clanger9 »

There are quite a lot of differences: the frame is taller and you'd have to change the crank, primary drive, etc. as well as the head & barrel.
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Re: Jammed oil pump

Post by SPRIDDLER »

clanger9 wrote:There are quite a lot of differences: the frame is taller and you'd have to change the crank, primary drive, etc. as well as the head & barrel.
Hmm, I didn't realise that they used different frames which explains why 250's aren't uprated to 350.

I see that Steve Surbey lists s/hand 'Lightweight crankcases' on his website so it may be worth Max giving him a call.
http://www.amcclassicspares.com/Secondhand%20Spares.pdf
Last edited by SPRIDDLER on Fri Mar 05, 2021 6:41 pm, edited 1 time in total.
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