AMC Box - freshly rebuilt, can't find gears

hrwat1

hrwat1

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Mar 30, 2013
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Well - just a quick query, I have a freshly rebuilt gearbox for my P11 - rebuilt by a mechanic i trust who works on Nortons (and knows more than me!).
All installed and in the frame, but when I try to flick through the gears I get a mixture of:
- hard shift (new box, hasn't been run yet - assume it will loosen up with use);
- no gear (ie I can move the shifter around but there is no resistance - but it will come back after working it round a bit); or
- working properly....

Any ideas on common causes of something like this? Clutch is working

The bike has not yet been fired and run since being taken apart - and the engine and box are both freshly rebuilt.
There is oil in both.

Also, does anyone know the thread on the bolt that holds the gear indicator in?

Huw
 
If the engine isn't running you need to turn the back wheel as you engage gears to give the dogs chance to line up. You can't just move through the gears with the bike stationary. If you're moving the wheel and it isn't engaging gears I'd get back to whoever rebuilt your gearbox.

Ian
 
Also check that the pawl spring, located in the outer cover, is installed correctly (looks like a hairpin). The offset (double crank) needs to be on the bottom for proper operation. This spring fits nicely with the offset top or bottom, but will only work correctly when on the bottom. This is clearly stated in the Norton shop manuals.

When assembling, it may even work a few times running through the gears with this spring in wrong-way-around, but will not keep working.

Hard lesson learned for me, with the help of Thomas (the torontonian) at Barber last year.
 
It my be wrong way round but the legs on spring may be bent incorrectly...I had same symptoms on Commando and fixed by proper bending of spring legs
 
hrwat1 said:
does anyone know the thread on the bolt that holds the gear indicator in?

Huw
Click to expand...

1/4d x 26tpi x 3/8"long P/N 04-0137 (domed head, as are many of the bolts on a P11)
 
Thanks all - much appreciated (I had noticed better feel when moving rear wheel - but hadn't quite thought it through).

Bolts all sorted (muggins here may have sheared it off with over enthusiasm) - easy enough to get back out.

Huw
 
BillT said:
Also check that the pawl spring, located in the outer cover, is installed correctly (looks like a hairpin). The offset (double crank) needs to be on the bottom for proper operation. This spring fits nicely with the offset top or bottom, but will only work correctly when on the bottom. This is clearly stated in the Norton shop manuals.

When assembling, it may even work a few times running through the gears with this spring in wrong-way-around, but will not keep working.

Hard lesson learned for me, with the help of Thomas (the torontonian) at Barber last year.
Click to expand...

No that torontonian would be Peter.
I think I caught that at Barber squinting in your Gearbox inspection cover with the flashlight.
Cheers,
Thomas
CNN
 
Alright, this may not be directly related to the last query but.....

Just setting up to kick and check spark (all wired) , can get one or so kicks in and then locks up solid at the kick (with plugs out) , usually preceded by a slight click, as if it dropped in to gear....turns fine by hand in reverse direction and fine both ways with clutch in ~ both ways in neutral.

Engine has been turned independently and turns fine (freshly rebuilt).

Thoughts?
 
You have wound the engine/gearbox forward by turning with the back wheel ?
What happens when you then try and kick it again. ??

Sounds like - obviously - something is not correct in the kickstart mechanism.
The pawl bizzo is catching on something....

What was replaced in that area ?
 
Wound back by socket on crank (rotor nut) - winds back and then has movement back to the catchpoint. When kicked will run back to that point and stop.
Will usually give one good kick and part of one more.

Has been suggested that it is something to do with the Pawl - although the spring seems fine. However, I recall that when unloaded (ie no chain attached) I could kick it round and round while adjusting the level of the clutch. This seems to suggest an alignment issue to me.

Entire gearbox was rebuild - would have to check invoice for what was replaced.

any suggestions?
Huw
 
You are either going to have to dig into this box yourself,
and see if you can spot where the trouble is.
Or run this by the rebuilder, and see what they have to say ?

Its most likely going to be in the outer cover, so won't (shouldn't) be a major dismantle to find.
But you won't know without someone having a look....
 
Thanks Rohan - I had a look in outer cover and it seemed fine but need to have a closer one with a better light / small mirror to check.
 
hrwat1 said:
Well - just a quick query, I have a freshly rebuilt gearbox for my P11 - rebuilt by a mechanic i trust who works on Nortons (and knows more than me!).
All installed and in the frame, but when I try to flick through the gears I get a mixture of:
- hard shift (new box, hasn't been run yet - assume it will loosen up with use);
- no gear (ie I can move the shifter around but there is no resistance - but it will come back after working it round a bit); or
- working properly....

Any ideas on common causes of something like this? Clutch is working

The bike has not yet been fired and run since being taken apart - and the engine and box are both freshly rebuilt.
There is oil in both.

Also, does anyone know the thread on the bolt that holds the gear indicator in?

Huw
Click to expand...

I wouldnt expect the "new G/B" to click over smoothly in the shed.... Share your thoughts with your "Trusted Mechanic".. IMO, I would let him know your dissatifaction and prepare him to revisit the G/Box... Do not disturb it cos he will know !! if you puk with it, hobot will teach you how to "whistle dixie"...
 
Tell us about the primary chain. How much slack has it on the upper level when cold.......... I ask because if the primary chain is over tight it will puk with gear selection and other issues will develop... Just another thought!! Feedback would be nice!!!
 
Thanks - as soon as I get in to the shed on the weekend to bottom this out, I will give some feedback.

The chain that is on there is old but I think it had a small but not excessive amount of slack. I have a new chain that just needs a couple of links taken out and it can be replaced.

Saturday will be devoted to sorting this one out...
 
Quick update.

Bike back - spent most of last night just fettling and checking. On gear issue, selector spring appeared to have been put in upside down (reading the AMC gearbox overhaul guide). Corrected this but not the root of the problem.

On the kickstart jamming front, off with the primary and the chain is under high tension (ie way too tight) - adjust the chain/gearbox position and the bike kicks again.
Successfully got to kcik and fire - will need to dial it in as the tune is way off (long process to get it to fire!) - but first need to chase down all the oil leaks and make a new outer cover gastket for the gearbox (wrecked it taking it off - v. annoying as it was brand new!).

Need to work on Stator/Rotor adjustment next - but on the P11 it is covered so adjusting the gap will be a bit of a trial and error process.

Huw
 
Quick update.

Bike back - spent most of last night just fettling and checking. On gear issue, selector spring appeared to have been put in upside down (reading the AMC gearbox overhaul guide). Corrected this but not the root of the problem.

On the kickstart jamming front, off with the primary and the chain is under high tension (ie way too tight) - adjust the chain/gearbox position and the bike kicks again.
Successfully got to kcik and fire - will need to dial it in as the tune is way off (long process to get it to fire!) - but first need to chase down all the oil leaks and make a new outer cover gastket for the gearbox (wrecked it taking it off - v. annoying as it was brand new!).

Need to work on Stator/Rotor adjustment next - but on the P11 it is covered so adjusting the gap will be a bit of a trial and error process.

Huw
 
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