CP Gearbox woes...

[stevewhitt]

Took my w/ng for its 1st ever ride this morning (it was a new bike to me in Sept.). All of the engine, wheels, clutch work I have been able to do with the assistance of the forum has gone well. The engine pulls like a train!
However, there is something wrong with the gearbox (or the way I partially assembled it).
Under no load and on the rear stand I was able to sequence the gears correctly. On the road, 1st was easy, but after that.....
It generally goes from 1st to 3rd/4th and finds a false neutral along the way. Coming back up, lucky if I can select anything until I reach 1st again. When I did manage to select 3rd/4th, it jumped out of gear under load.
Gearboxes have always been a black art to me, but I am willing to dive in and take a look. I have verniers and micrometers.
I removed the end cover and was surprised to see gearbox oil in the case. It looks like it is entering via the mainshaft/inner cover bearing - is this normal?
That aside, any advice on where to start would be greatly appreciated.
I have attached some photos of the outer case components.

[JohnnyBeckett]

hi i think you need to look at the gear change selector, the selectors and springs stick and springs go weak

[stevewhitt]

Hi Johnny, I stripped the selector down. It was well greased, no broken springs and not much wear as far as I could tell. I happen to have bits of a spare gearbox, including a selector which I also stripped down and compared with my original. The main springs on my spare are 5mm longer, but that is the only difference. The only other thing I noted is that the metal plates which abut the springs do have some wear marks (grooves) in them.

When you assemble the gearbox, does the gear sector quadrant go in a central location (i.e. in the middle along its length of travel onto the camshaft) - that is how I assembled it.

[stevewhitt]

Hi Johnny, I stripped the selector down. It was well greased, no broken springs and not much wear as far as I could tell. I happen to have bits of a spare gearbox, including a selector which I also stripped down and compared with my original. The main springs on my spare are 5mm longer, but that is the only difference. The only other thing I noted is that the metal plates which abut the springs do have some wear marks (grooves) in them.

When you assemble the gearbox, does the gear sector quadrant go in a central location (i.e. in the middle along its length of travel onto the camshaft) - that is how I assembled it.

[simon.holyfield]

When you put the quadrant back in, there are two timing marks - small punched circles - which must align. One on the quadrant, one on the selector drum pinion. Did you see those?

[volker.halbach]

I had a similar problem. The peg in the control quadrant had come loose and was not always engaging. But probably you would have noticed that already.

[SteveShone]

When you assemble the gearbox, does the gear sector quadrant go in a central location (i.e. in the middle along its length of travel onto the camshaft) - that is how I assembled it.

Not quite assimple as that, Steve. on the end of the selector shaft you'll see an '0' stamp in the valley of two teeth. Position the selector shaft so the 0 is at the 9 oclock position. Its actually a false neutral between 2nd and 3rd. The selector quadrant has a similar 0 mark but at the peak of one tooth, about half way alongthe quadrant - line them up as you put the quadrant into position. Then its the juggling to get the spring box over the pins. Much easier with the box on the benchbut can be a challenge when its in the bike. I learned new combinations of anglo saxon when I did the box on my Matchless last week
I think your box should bd grease filled rather than oil unless its had the output shaft seal conversion. Theres no difference in the internals that Im aware of. I use Penrite semi fluid grease (sometimes referred to assteering box grease) with an eggcupful of 140 oil tipped in for good measure. The oil filled boxes normally have a level plug just behind and below the kickstart shaft.

Hope this helps. Steve (I see Simon posted whilst I was typing!)

[stevewhitt]

Well, just goes to show 'you don't know, what you don't know'! I have reassembled as per above instructions, test ride tomorrow morning.
It was a struggle getting everything lined up, I think I can add to your angle saxon dictionary Steve. I wrongly referred to my semi fluid grease as oil. My question regarding 'should it have made it into the front cover' stands though.
Thanks everyone who replied.

[SteveShone]

Some will make it through into the outer case eventually, in fact I normally squirt a good dollop in there on the basis that there are moving parts in there and itll not do any harm. In an oil filled box the oil finds its own level between the two areas anyway.

Steve

[Roger Gwynn]

Pre 1944 boxes do not have any holes for the grease to get into the outer compartment or kick start case but some will find its way past the bushes and bearings. There should be a steel sealing washer on the bearing and parts inside that cover should be greased. I have found that the condition of the springs in the spring box make a lot of difference, 5mm shorter will make a lot of difference.