[dvnr] Fwd: Level Three Norton Gearbox Repairs

[bob Katz]

I will hold u to that Sammy offer and enjoy every little bite. Lol

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 On Saturday, July 13, 2019, Brian Safer via DVNR <dvnr at casano.com> wrote:

Greetings Boys,

As some of you know, I suffered a gearbox failure on my Norton after returning from the INOA Ralley in Michigan. A call to Sellers Recovery and Repair Service fetched me from Upper Black Eddy to the Level Three Motorcycle Repair workshop here in bucolic Penns Woods. The initial diagnoses from such mechanical savants as Dan Sellers, Dave Benkhen and Bob Katz indicated layshaft bearing - whatever the hell THAT was.  Ive never been inside a Norton gearbox and the only motorcycle transmission Ive done anything with is simply removing the entire thing from a T140. Having been encouraged by some folks at the First Sunday breakfast telling me that "its not a big deal" and Frank Mohr relating that he once rebuilt a transmission in a parking lot in Daytona with a pocket knife, I figured how bad can this be? Bob Katz tried to talk me into removing the whole gearbox, but that sounded like a lotta work.

So away I went. My first obstacle was removing the clutch operating mechanism lockring. I made a tool from a 1 1/2" pipe nipple that did the trick. Next, I got all but ONE of the inner case mounting nuts off - but Dan had a thin wall socket that fit perfectly. I thought I could just get the mainshaft nut off with a cheater bar, but no luck - so resorted to a pneumatic impact wrench - et voila. I started to withdraw the cogs and removed the spindle that the selecting forks were mounted on. After withdrawing the cogs, layshaft and forks,  I immediately saw the pile of ball bearings in various stages of disintegration piled up in the case well where the layshaft bearing should have been. The inner bearing race was attached to the end of the layshaft. The outer race remained in position. I got a magnet and fished out all the metal shards, then flushed the case several times with brake cleaner to debride the cavity until I couldn't find anymore loose metal bits or metal powder.  

Now I had to remove the outer race. Heating it and pulling it with a bearing puller was the preferred method, or if the gearbox was removed it was even easier.  I fashioned a bearing puller of sorts with a gear puller and was able to get the race out after two or three slaps with a large socket as a dead weight on the threaded shaft.  I was aware that there could be a crack in the case where the sleeve bearing and layshaft bearing were only milimetres apart. Clever design. And you guys think Im level three???  I flushed the race cavity and used the magnet and cleaned out the debris. I got a small mirror and inspected the outer race mounting surface. I found a small crack.  

Attached are a few pics - my initial view of the ball bearings, the worn kickstart pawl, the small crack and some of tools I used.  So now Im torn - ball bearings vs. roller bearings. Most say roller bearings - but two people I know and respect tell me ball bearings - so Im tempted to stay with ball bearings and reduce the need to adjust layshaft end float. Besides, I think they are now made in Argentina instead of Portugal (like that's an improvement????).  Regardless 45 years of service aint bad - Ill be dead in 20 - or at least probably not riding the Norton. The more critical question is about the crack - remove the gearbox and repair?  Then I probably owe Bob Katz a sandwich or something.

Brian


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