Hi all friends, I have a question about the oil pressure sensor (the button that is displayed in case of pressure). I know from the photos that the first models mounted it, then it disappeared. I wanted to know if anyone had any information about it. In particular up to the year in which it was assembled and if documentation on the subject is available (photos, cards, etc.).
I have always liked the look of the oil pressure gauge on the early KM’s, and have only ever seen one in real life fixed to a beautifully restored KM 20 at the War & Peace revival show last year.
I don’t really know the answer as to why BSA stopped fitting them. It may due to time and cost of manufacturing or perhaps the gauge it’s self was prone to being smashed off whilst cross country and dropping all its engine oil ?
The WD16H which had a 1937 pattern engine throughout, retained the timing cover oil tell-tale but the SWD Big 4 which used the 1938 type engine was introduced without one...It had been deleted by Norton as part of their move towards 'cleaner' lines and it was one less thing to leak !
Perhaps oddly, they were fitted after a year or two and this required a new type of 1938 pattern timing cover...Presumably it was at War Office insistence, otherwise they wouldn't have accepted the extra costs, but then why was it deleted from the BSA ?
I rather like mine on my Snide and Shark 16H. It's sort of comforting. I also like a 19 tooth engine sprocket; then the narrow gap between 3rd and 4th makes perfect sense and gives the bike an almost M21 long legged feel
Lex, Ron typo'd "by" for "my" and it changed the sense of it.
The BSA type of tell-tale was much more logical in its tank panel location. Stuck on the timing cover does seem like an after-thought and an easy way of losing all oil pressure if damaged.
This is the last M20 that I have on file with the tell-tale. C4198701 from Contract C6654. I calculate that it is WM20 23189 which would have been delivered mid-1940. Does that tie in with Henk's findings ?
I believe that you're correct, Mauro. I also believe that you have just set yourself the task of finding a 1939 or early 1940 KM or WM20...:grinning: They are rather nice !
Friends, I have a problem, the screw of the engine block where the oil pressure indicator should be connected does not unscrew :-( ... what can I do? Do you have any suggestions? Has the thread turned upside down or is there something that do you have to do to remove it without doing damage?
Yes, if heating of the case doesn't work either you could MIG weld a nut on the plug.
That always works for me when bolts/studs are real stuck or broken off, sometimes need several attempts but in the end they all give up, usually with no damage to the aluminium en mostly the bolts/screws can be used again after some grinding/filing :relaxed: