I've had my '75 Norton 850 Commando more than four months, and I've yet to ride it.

I've replaced a few parts in the gearbox shifting mechanism (selector pawl, hairpin type spring, "O" ring and circlip tha6t holds the selector pawl captive, but something else is keeping the thing from downshifting.

It will upshift, and I can get it to upshift and downshift on its stand by pushing on the selector, but once buttoned up, it will not downshift.

Any suggestions would be greatly appreciated.

Is the clutch dragging?

Are you certain you 'set' the pawl spring correctly? This involves bending it to eliminate selector bias (gears select much better in one direction than the other).

L.A.B. wrote:Is the clutch dragging?

Are you certain you 'set' the pawl spring correctly? This involves bending it to eliminate selector bias (gears select much better in one direction than the other).

Although the clutch is a bit hard to pull, in shifting up, it works fine.

I am unaware that some magic has to be done with the spring.

I do know that the spring should have about .010 clearance, but it seems like the spring isn't captivating the pawl.

When it does this what does the gear lever do ? Does it feel solid or does it move but feel slack?

Trying to select gears with the bike on the stand with the rear wheel on the ground with the engine running won't help with gear selection if that is what you are doing? (my own Mk3 I'm sure would not easily select all gears if I were to do that) As ideally the bike should be moving forwards or at least the rear wheel should be off the ground?

L.A.B. wrote:When it does this what does the gear lever do ? Does it feel solid or does it move but feel slack?

Trying to select gears with the bike on the stand with the rear wheel on the ground with the engine running won't help with gear selection if that is what you are doing? (my own Mk3 I'm sure would not easily select all gears if I were to do that) As ideally the bike should be moving forwards or at least the rear wheel should be off the ground?

I'm giving information second hand. My son's buddy, who was a motorcycle racer (road) is doing the work. I'm interpreting his input.

He didn't know that the spring needed anything but to "capture" the wedge shaped "pawl" that moves up and own. It seems that at first this happenes, but when he took it out, it upshifted well and even downshifted... once, then not again.

Looking at the exploded drawing, that pawl, part no. 04-0024, seems to be capytured by the spring, part no. 04-0038.

At first, I thought it was missing the circlip that keeps it on the pawl pivot pin, but that was on and tight.

I'm wondering if the bushing, part no. 04-0473, or the inner gera shift bushing., part no. 06-5184, might be too loose, allowing the Carrier Pawl Assembly to allow the pawl to get by the spring.

Noe, I'm trying to line up an experienced Norton mechanic in the Phoenix area to help solve this problem, or to devine a magic fix.

rocketdoc,

If you email me at <powers.one@ntlworld.com> I will send you detailed information on how to check and set the pawl spring.