Layshaft Stuck

Niagara850 said:

I looked at the current Mick Hemming price list and didn't see a ball bearing listed, just a roller. Maybe it isn't available anymore. Anyway is old reference cataloge has this listing

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http://www.mickhemmings.com/ >Mick Hemmings Catalogue 2005 (Ignore Pricing) Reference only.
pdf p.8

"SPECIAL RACING BALL BEARING, THE ANSWER! TX1366

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Niagara850 said:

Layshaft Bearing (Standard Type) O4 0100 3.13
Roller Replacement for above (Not recommended) 06 7710 16.25

A confusing choice of wording?

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04-0100 The original ball bearing
06-7710 The roller replacement (now the standard AN part - but not recommended by Mick H)

Aha! just had to keep reading... or better yet called and got a current price too

Ok , got around to re-assembly, the bearing went in much quicker than coming out and the box went together without fanfare, tested shifting through the gears and neutral. I measured the end play to 0.085'. Is this excessive or in the normal range? I guess my choices are 2 x 0.30' + 0.020 iso shims for end result of 0.05' or 2 x 0.030 + 0.010' + 0.005' for an end 0.010' play. which is better loser or tighter. I see Old Britts target 0.005"

.005 seem a little thght to me.
Not that you are asking but.......
I believe there are 2 alternative options to shimming.

1 would be to shim behind the outer race in the casing but the thought of removing and replacing the outer seems just too evasive on the soft machined surfaces.

The other would be to shim behind the inner race in the layshaft. This option seems much more plausible. Shimming the kickstart shaft as OldBritts does is ok but too wishy washy and inconsistant IMHO.

Please do not consider this an argument to your choices, but I have gone with a good ball bearing but remain open minded and will continue to research these options. My current thoughts are if the layshaft is allowed to float, is there a need for a thrust washer somewhere?

Here is a quote from Jim Bush (jba@express.ca) on NOC-L 1st. Sep 1997
"I don't believe it would need a thrust washer as the first gear shoulder on the layshaft, and not the face of the bronze bushing in the kick-start spindle, prevents lateral movement."

I think any of the modern solutions will work fine when accompanied witth good bushing, proper lubes, a good working clutch and sound shifting practices.

Shimming the kickstart end is correct, it locates the layshaft where it originally was positioned by the ball bearing. (the shoulder on the roller bearing is the locater in the LH direction) The original ball bearing held it with no endplay, so the .005" clearance suggested by OB is a good number, just enough to allow lubrication in between shims on the right, shoulder on the left.
This retrofit of a roller bearing in place of a KNOWN PATTERN FAILURE ball bearing is a no brainer because: It's a safety issue. A locked rear wheel is not a joke, nor is it romantic, nostalgic or any of that crap. There's a good chance you'll need skin grafts.. if you're lucky. Get driven over if your not. Like a the airbag in your car, it may be overkill, but it's comforting to know it's there. Unlike the arguments over which carb/ignition/oil is the end of the rainbow, this can put you in a wheelchair, not just sputter to the side of the road or make you the object of ridicule as you kick repeatedly on a bike that won't start.
Take advantage of the lengthy history and put it to use.

fwiw , researching the forum et al

The FAG 6203 TB.P63 ball bearing or FAG NJ203E C3 roller bearing will both suit the purpose. I haven't found evidence of either failing. The ball bearing has the advantage of not requiring shimming and the roller bearing is stronger dealing with axial loads. In my case the roller was readily available at a somewhat lower cost( but when I add the shims and shipping it's a wash). The Ball was on back order. So I took the expedite route. As long as its shifts nicely when I'm done I'll be happy, and no worry of catastrophic failure.