No oil to rockers model 8

Information relating to the Matchless G5 or AJS Model 8 350cc Lightweight
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Les Howard
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Re: No oil to rockers model 8

Post by Les Howard »

As far as I know, the oil way to the top of the crankcase is direct from the front of the pump so once you see a good flow I doubt if further blockage is likely....Ozmadman has a good set of photos and is likely to know after his recent rebuild.....of the engine of course.....Les.
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Ozmadman
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Re: No oil to rockers model 8

Post by Ozmadman »

Les P H wrote:As far as I know, the oil way to the top of the crankcase is direct from the front of the pump so once you see a good flow I doubt if further blockage is likely....Ozmadman has a good set of photos and is likely to know after his recent rebuild.....of the engine of course.....Les.
Yes, that hole goes all the way down to the pump shaft and beyond to the bottom of the crankcase but your wire would stop at the pump, see the picture attached. The oil is pulled up by the pump from the bottom of the sump and pumped up to lubricate the timing side bush, gear and the rockers (there is a post on here somewhere that shows the exact route the oil circulation takes but I can't find it at present) if the bottom section of that hole below the oil pump was blocked then you would have no flow or return at all so I reckon your poking around down to the pump will do it. The cam shaft bushes, cam and cam followers are lubricated by the oil running down from the head, down the large push rod hole in the barrel and into the cam housing which fills up with oil to the vent hole halfway where it drains into the oil tank. I presume that the two roller bearings are "splash" lubricated as there are no oil feed holes to them. The other return hole you see oil coming out of is the return from the pump via the filter
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Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
irsooty
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Re: No oil to rockers model 8

Post by irsooty »

Hi all, sorry it has been so long since I last was here.
I am glad to tell you all I now have oil at the rockers!!😃.
In the end I had the head and cylinder off, many hours of fishing about and blockage was clear!
I will post pictures of what was found down there!!!
Thank you all for your help!!
Iain.
irsooty
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Re: No oil to rockers model 8

Post by irsooty »

Someone went a bit O T T with instant gasket!!
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Ozmadman
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Re: No oil to rockers model 8

Post by Ozmadman »

The manual states not to use any jointing compound on that barrel to crankcase gasket so that is probably why, I always use a thin smear of wellseal sealer as that is a thin liquid which cannot flake off in lumps that can block oil ways like hermetite or hylomar can. Just looking at your second picture... Is that the remains of the smaller head bolt thread I see or is that ok?. That one should just be nipped up tight when you put the head back on whereas the other 4 larger studs are 35Lbft. Mine was completely stripped and had been helicoiled at an angle which was also stripped, I ended up making a 10mm coarse threaded stud and fitting it permanently into what was left of the hole in the barrel and then drilling out the head to take the larger stud. works fine and no head gasket leaks
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
irsooty
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Joined: Sat Sep 05, 2015 3:43 pm
Location: NORFOLK UK

Re: No oil to rockers model 8

Post by irsooty »

The thread was ok, but I may have tightened it up a fair bit when putting it back together!
The bit in pic 1 was 2inches long but I chewed a fair bit up whilst digging! Actually I got what I thought was all of it but when I started her up a dribble of oil came out and stopped, when I had the rocker cover back off that bit was stuck in the cover, pressure had forced it up for me!
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Ozmadman
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Re: No oil to rockers model 8

Post by Ozmadman »

Here's a few picture of the said stud mod
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Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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