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1949 Model 16H Primary Drive Cover Dimensions

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Good day, guys!

I have a 1949 Model 16H I acquired last October and am spending the winter fettling a few items.

I have removed the engine and gearbox for a quick evaluation and refresh as required, and am also taking the opportunity to clean up the frame and miscellaneous ancillaries.

As part of this, I am stripping and repainting the primary drive cover, but upon removing it, I realized that it seemed too large for the backing plate, and the sealing gasket was poorly-fitted.  I had another cover in the parts bin, so I'd a side-by-side comparison and concluded that the incorrect cover had been fitted, but I want to ask the experts to weigh in.

The attached file labeled "Marked-up Primary Drive Inner Cover & Assembly" shows the dimensions of the inner cover as well as the two outer covers.  Apart from the difference in length, the larger cover, the one fitted to the bike when I bought it, has a larger relief for the engine sprocket.  This is shown in the attached file labeled "Primary Drive Comparison." 

Another difference is that the larger cover has a smaller diameter drain plug than the one shorter one.  This can be seen in the attached photo labeled "Primary Drive Drain" which shows the drain plug from the larger cover next to the drain hole on the shorter one.  For general reference, I have also attached a photo of the inner cover labeled "Primary Drive Inner Cover."

Because things seemed to fit together well with the inner assembly in place, I believe it to be correct.  I also believe the shorter cover I pulled from the parts bin to be the correct one, because it fits the inner cover better and the engine sprocket relief more closely matches the illustration in the factory parts manual.

Can you guys please weigh in and let me know your thoughts? 

  • Which cover is correct for my machine?
  • Can you guys let me know what model the incorrect cover might fit so I can make it available to other club members? 
  • Finally, can you all please provide some guidance on where I might find the correct gasket to go between the inner and outer covers

Thanks!

 

-Robert

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The attached pages are from a mid 1930s Norton Singles parts book. However, on the inside is a 1948 red sticker pointing out that little apart from the price of the various bits and the book has changed.  The pages show the variations of covers at that time.  These may be of help.

In reply to by philip_hannam1

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Thanks, Mr. Hannam.

This is quite helpful.  I think I'll run the non-alternator cover and call it good enough.

Do you have any thoughts as to where I could purchase the correct gasket for the shorter cover?  All the ones I have seen recommend buying a larger gasket, cutting it down, and joining it with super glue.  I can certainly do this as a stop-gap measure, but I would strongly prefer to fit a gasket made as one continuous piece.

Thanks again!

-Robert

 


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