As has been said, it may help sumping or not but if you do not know how it looks in there then you are a fool to be driving it when or if it blows up. Norton did not care, you aught to, I have seen them blowing oil out the side of the gasket were the "machining” marks are so deep and or positive that no paper gasket could hold fast. Follow this simple rule if there is no oil on the stick, don't start it. (Drain it) Never rev it hard if you think the sump has too much oil. (Over 200cc’s) I have done 25 or so pumps all of them needed some work it's not that bad a job just do it. Be sure to use a pioneer brand seal in the cover for the crank it's all the oil has to push against. I have a few more tools since this set of pictures was taken I need to update my work. The thread that went with it got deleted a long time ago I do have my own opinions perhaps they were too freely expressed. Oh well, No harm was done to Norton’s
