Gearbox issues

fiatfan · Aug 19, 2017

It doesn´t show very well in the pic, but I got a feeling the quadrant isn´t aligned with the housing.

Since the bolt just turned around and around and nothing else happened, this was the only way I thought.

Out!

Here you might see what I mean a little better, lookes "wobbly"?

rvich · Aug 19, 2017

Is there a specific fault with the gearbox?

I have always pulled the quadrant before pulling the cam plate. So it has never occurred to me that it might spin clear round if the cam plate is removed. I think that would be normal.

These parts are often not finished off as nicely as possible. (understatement) So one could polish up rough edges. The critical areas here are the teeth, the fork for the roller and the shaft. Yours looks pretty good to me. When the shaft is inserted into the shell does the fit feel correct or "wobbly"?

Russ

L.A.B. · Aug 19, 2017

rvich said:
I have always pulled the quadrant before pulling the cam plate. So it has never occurred to me that it might spin clear round if the cam plate is removed. I think that would be normal.

It wouldn't be normal, but what I think he means is that the spindle is loose in the quadrant.

fiatfan · Aug 19, 2017

Ok, maybe I wasn´t clear enough. What had happened was that the bolt turned in the spindle, but didn´t come out no matter what. Threads gone.

Tommy

rvich · Aug 19, 2017

Ah! Seems you have a list of options:

1.) Use JB Weld or similar to build new threads
2.) Put in a Helicoil and use the original bolt
3.) Tap it out for a larger bolt
4.) Buy a new quadrant.

I would probably lean toward #3 but everyone has their own standards to live up to. I believe the shell is bushed, so it is possible to renew that bore if it seems like a poor fit. I don't have a quadrant handy without tearing down a gearbox so I can't compare photos, but yours looks pretty standard other than the threading issue.

As for alignment, I would install the cam and the quadrant and see if the cam goes through all the "clicks" without any binding or rubbing.

Russ

fiatfan · Aug 19, 2017

rvich said:
Ah! Seems you have a list of options:

1.) Use JB Weld or similar to build new threads
2.) Put in a Helicoil and use the original bolt
3.) Tap it out for a larger bolt
4.) Buy a new quadrant.

I would probably lean toward #3 but everyone has their own standards to live up to. I believe the shell is bushed, so it is possible to renew that bore if it seems like a poor fit. I don't have a quadrant handy without tearing down a gearbox so I can't compare photos, but yours looks pretty standard other than the threading issue.

As for alignment, I would install the cam and the quadrant and see if the cam goes through all the "clicks" without any binding or rubbing.

Russ

Well I´ll probably go for #4, even though there´s already lots of things I´ll have to buy for the box. So one more thing.... :mrgreen: I just got the two bearings out of the shell, and guess what? No good, buy new! And the kick start shaft has been welded, and so on, and so on..... :shock:
I´ll put the quadrant back with the cam as you suggest, see the alignment. But the quadrant doesn´t look right, not straight. Hard to get on a pic though.
Tommy

gortnipper · Aug 19, 2017

No, it does not look 90 degrees.

gripper · Aug 20, 2017

Be careful when tightening the two screws in the camplate and quadrant, It's easy to chip the first tooth off the quadrant.

fiatfan · Aug 20, 2017

This is how it looks when both the cam plate and the quadrant is in place. Obviously not right, the quadrant is touching the cam plate, I think you see very clearly on this pic that it´s not in a 90 degree angle.

And there´s more...is the surfaces on this fork ok? Looks strange....

And the lay shaft bearing doesn´t seem to have been set properly.

.....sigh......
Tommy

L.A.B. · Aug 20, 2017

fiatfan said:
And the lay shaft bearing doesn´t seem to have been set properly.

What often causes that rub mark is when layshaft '4th' gear has been fitted back to front, so the flat side of the gear is up against the bearing.
The layshaft bearing goes all the way in up to the shoulder. If layshaft 4th gear is installed correctly the sleeve gear bearing possibly isn't in far enough.

Hopefully, you already know the layshaft ball bearing should definitely be replaced with either the roller or Hemmings bearing upgrade.

fiatfan · Aug 20, 2017

L.A.B. said:
fiatfan said:

And the lay shaft bearing doesn´t seem to have been set properly.

Click to expand...

What often causes that rub mark is when layshaft '4th' gear has been fitted back to front, so the flat side of the gear is up against the bearing.
The layshaft bearing goes all the way in up to the shoulder. If layshaft 4th gear is installed correctly the sleeve gear bearing possibly isn't in far enough.

Hopefully, you already know the layshaft ball bearing should definitely be replaced with either the roller or Hemmings bearing upgrade.

Thanks for info, I suspected something like that. Unfortunatly I didn´t pay attention when I removed the layshaft, so I don´t know which way the gear was fitted....

But I guess it was the wrong way. I´ll replace both bearings, the small one too, that actually didn´t have any markings on it, so I guess it´s a really cheap one.
Tommy

rvich · Aug 20, 2017

Are you familiar with the Mick Hemmings Gearbox Servicing DVD? It provides quite a lot of comfort when sorting through the pieces.

http://www.nortonownersclub.org/shopping

gortnipper · Aug 20, 2017

rvich said:
Are you familiar with the Mick Hemmings Gearbox Servicing DVD? It provides quite a lot of comfort when sorting through the pieces.

http://www.nortonownersclub.org/shopping

+1

Gearbox issues

fiatfan

rvich

L.A.B.

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fiatfan

rvich

fiatfan

gortnipper

gripper

fiatfan

L.A.B.

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fiatfan

rvich

gortnipper

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