AJS & Matchless Owners Club

Hi all, I am having difficulty maintaining an oil feed to the top end of my 51 g80 engine. When I first rebuilt the engine I replaced the oil pump. Later (don't ask me why) I purchased another one giving me three old pumps. One old and two new. When I look at the three together I noticed the new one is drilled differently. The two older ones have been drilled to index the delivery port at the bottom of the pump stroke whereas the new one indexes nearer to the top (in relation to the machined helix). I also notice that the inlet ports are drilled differently. I do not know if the newer one was designed to increase oil flow to the top end and, if so, does this reduce the oil to other areas (big end etc). Can one of you g80 gurus enlighten me. I have attached some photos showing the three pumps with the old one in the middle, the newer one (which was installed earlier) on the left and the most recent one on the right

Further to my last message I revisited the AMOC site where I purchased the two pumps and noticed there are two different pumps with different part numbers. The one I replaced uses part No. 012967. The latest one I purchased comes under the part No. of 042104. Can anyone explain the difference please?

Chris Berry wrote:Further to my last message I revisited the AMOC site where I purchased the two pumps and noticed there are two different pumps with different part numbers. The one I replaced uses part No. 012967. The latest one I purchased comes under the part No. of 042104. Can anyone explain the difference please?

012967 is for a heavyweight single (Section “A”), 042104 is in Section “C” and therefore a lightweight single part.

Your parts list will tell you the correct part for your model/year.

Stuoyb wrote:

Chris Berry wrote:Further to my last message I revisited the AMOC site where I purchased the two pumps and noticed there are two different pumps with different part numbers. The one I replaced uses part No. 012967. The latest one I purchased comes under the part No. of 042104. Can anyone explain the difference please?

012967 is for a heavyweight single (Section “A”), 042104 is in Section “C” and therefore a lightweight single part.

Your parts list will tell you the correct part for your model/year.

Thanks Stuoyb. I'm gad I looked at the pump before I put it in the bike. I guess if anyone wants a pump plunger for a lightweight single her In Australia I have one in my spares box