Hole in front of oil tank

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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AdieB
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Hole in front of oil tank

Post by AdieB »

I just started to put oil in the rebuilt engine of my AJS 14, when the oil started to pour out of a hole at the front of the oil tank. Does anyone know what this hole is for? Can I bung it up somehow if it is not required? I really cannot see what it is for. With the hole there, I am unable to fill the bike to the correct oil level. Many thanks for any help.
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oldgit61
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Re: Hole in front of oil tank

Post by oldgit61 »

Just checked an there isn't a hole in my G2's crankcases. Personally I'd tap it and put a short bolt in it.
cbranni
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Re: Hole in front of oil tank

Post by cbranni »

Drilling a hole there is one way of knocking out the oil pump shaft if it's very tight, simple fix is drill and tap the hole and plug it with a bolt. Sadly it maybe a sign of a previous owners butchery and you may want to investigate further.

Colin
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clanger9
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Re: Hole in front of oil tank

Post by clanger9 »

Yes, that hole shouldn't be there - and it's exactly in line with the oil pump shaft (as you can see in this picture of an unmolested crankcase).
IMG_1734.jpg
It needs to be tapped & plugged.
Who rebuilt the engine? As Colin says, check that everything else is OK in the oil pump area...
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AdieB
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Re: Hole in front of oil tank

Post by AdieB »

Many thanks for your thoughts on this. I can see that the hole is directly in line with the oil pump, so it looks like this is the answer. I will tap the hole and put in a bolt to seal it up. Another mystery solved! Thanks again.
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Rob Harknett
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Re: Hole in front of oil tank

Post by Rob Harknett »

oldgit61 wrote:Just checked an there isn't a hole in my G2's crankcases. Personally I'd tap it and put a short bolt in it.
Yes hole in crank case.
Ashampoo_Snap_2018.10.11_19h40m41s_022_.png

I thought oil tank was within the crank case.????????
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alanengineer
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Re: Hole in front of oil tank

Post by alanengineer »

Rob
Until i saw the photo that clange9 put up, i also thought the kidney shaped oil tank was all of the tank. but no, its just a shaped cover that bolts to that crankcase half to make a bigger tank. see gasket 042170. Its a cleaver design to make a big oil tank.
oldgit61
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Re: Hole in front of oil tank

Post by oldgit61 »

Rob Harknett wrote:
oldgit61 wrote:Just checked an there isn't a hole in my G2's crankcases. Personally I'd tap it and put a short bolt in it.
Yes hole in crank case.
Ashampoo_Snap_2018.10.11_19h40m41s_022_.png

I thought oil tank was within the crank case.????????
The in the drawing hole should be there, it's at the back of the crankcase, the one in the original picture is in the front of the crankcase and shouldn't be there.
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Rob Harknett
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Re: Hole in front of oil tank

Post by Rob Harknett »

alanengineer wrote:Rob
Until i saw the photo that clange9 put up, i also thought the kidney shaped oil tank was all of the tank. but no, its just a shaped cover that bolts to that crankcase half to make a bigger tank. see gasket 042170. Its a cleaver design to make a big oil tank.
Long time since had a light weigh apart Alan. Back in the 80's I had a shed load of parts among which was a box full of oil tanks. This topic has been a memory jogger, I do now recall they were just shells. I got the parts from a dealer, fed up with carting them about, in exchange for an almost complete C12 BSA and spare engine. I made up best part of one light weight. Then got rid of what must have been remains of 6 bikes. As there were at least 6 oil tanks. I would have made a good return for my £50 spent then, if I still had all those parts now. No one wanted them then. I brought almost complete bikes for £120.
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