bike pedigree
- Thread starter thecallowyouth
- Start date
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- Joined
- Sep 5, 2005
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- 8
For those seeking the internal or is that infernal information, here is the scoop for those wondering what is inside.
The "oil control piston" mentioned with the slots was introduced in the 1971 manufacture year around engine # 146584 according to the Service Release sheets. They altered this piston for the Combat and went to a different control ring also at engine # 200976 again according to the Service Release notes. If you fall into this catagory and don't know well winter is fast approaching, and it is easy for the 750 owners to pull the barrels without pulling the head.
Norton was having mutliple issues with oil comsumption and the "Oil Control Piston" was one way they thought they could cure the problem. The idea was to open out the oil passages in the piston to allow the scraper ring to quickly pass the oil off the barrel into the crankcase. In so doing the piston tops used to come off. This was known to be more prominent in motors that were wrung a little harder. Now let's all remember that they discovered the problem within a year of manufacture, so the chances of any machine still having them in with considerable mileage on the clock is fairly rare. This is not to say you don't have them, but if your 750 shows more than 50,000 on the clock I would think you are safe to continue riding.
Cheers,
Steve Jowett
The "oil control piston" mentioned with the slots was introduced in the 1971 manufacture year around engine # 146584 according to the Service Release sheets. They altered this piston for the Combat and went to a different control ring also at engine # 200976 again according to the Service Release notes. If you fall into this catagory and don't know well winter is fast approaching, and it is easy for the 750 owners to pull the barrels without pulling the head.
Norton was having mutliple issues with oil comsumption and the "Oil Control Piston" was one way they thought they could cure the problem. The idea was to open out the oil passages in the piston to allow the scraper ring to quickly pass the oil off the barrel into the crankcase. In so doing the piston tops used to come off. This was known to be more prominent in motors that were wrung a little harder. Now let's all remember that they discovered the problem within a year of manufacture, so the chances of any machine still having them in with considerable mileage on the clock is fairly rare. This is not to say you don't have them, but if your 750 shows more than 50,000 on the clock I would think you are safe to continue riding.
Cheers,
Steve Jowett
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