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Discussion Starter · #1 ·
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Gear Household hardware Engineering Nickel Machine

I thought I would add a little story today. Once upon a time, in a greasy shed in the backwoods of NJ…
The pre-unit I purchased a few years back had some transmission issues. Putting it into first gear without making noise, was crunchy but gradually got worse. Come to find out the belt drive was way too tight and so was the chain. Totally my fault and shame on me for not going over the bike before riding it for a year. That dumb mistake cost me.

Long story short, I finally decided to pull the transmission apart and guess what I found.
Layshaft first gear, Layshaft second gear, and Layshaft third gear have damage. Inner teeth chewed up and the fork was all blue and overheated. Not to mention the gearbox bushing was worn the F out as well.

No choice but to do a full rebuild. Sealed bearing on drive side (open bearing on other) along with needle bearing conversion as well and of course the belt pully on the crank was damaged. Special thanks to Bob Newby (from across the pond) for sending out a new one. Great guy btw. This little project set me back at least 500-600$.

Oh did I mention the bottom pivot bolt that holds the transmission at the bottom of the frame was worn out. Had to buy another case with decent mounting holes…
The end.
 

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The sealed bearing you have to cut a bit of the shaft ?
I did on mine
 

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Discussion Starter · #7 ·
Like you cut a bit off
Because now your closed needle roller
I dug up some information on issues with converting a preunit gearbox from brass bushings into needle bearings.
Apparently when doing this the stock layshaft no longer works and sticks out creating a problem with closing the cases. But the layshaft from 1961 to 1963 is shorter and will work with needle bearings.
 
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