Britbike forum Forums British Motorcycle specific Brands Norton bulletin board 1970 Commando points cam removal

In process of removing oil pump to address wet sumping.

Archives refer to a couple special tools (e.g. My 'From 1970' WSM specs 064298)
There is also a discussion of actually using the tool's slide hammer vs lightly tapping the tool sideways, I assume to jog the taper interference fit.
Anyone care to comment so I can blame them when the cam breaks. :-)

Cheers

With a line like that, you could go far in politics !

Special tool ? For removal ??
I've never had any problems taking it off.
Be gentle, no need for ham fistedness here.

You do need the little tapered tool thingy to replace the cover though,
it avoids damage to the oil seal.

btw, the original cam was STEEL, anyone who can break that really was ham-fisted ...

Assuming you aren't going to use a sledgehammer then screw in the tool (or any 5/16" bolt* long enough to bottom out) and partially tighten, then tap the head of the tool/bolt sideways. This information is given in Norton Service Release N3/31 which recommends against a "straight-pull" only to extract the auto-advance.

*Edit:
Early AAU extractor thread is 5/16" x 26. Late is 5/16" x 24 UNF.

The (gentle) sideways tap is to break the taper joint, which a straight pull out may not do.

All the AAU i've removed are 5/16-24 UNF If you put in a pre made 1 peice tool it will bottom out in the cam and when the screw is tightened it is a self extractor.
A regular bolt with a separate smaller than 1/4'" rod will also work as a self extractor.
a small slide hamer with a 5/16# 24 screw-in bit works.
The side ways tap also usually works but I rarely use that method.

an old stator mounting stud from the other side will have the thread to screw inyo the AAU.

i do that, then grip the stud with vise grips and tap it gently with a hammer while pulling on the stud.

ive never had a tight one.

Thanks for all the tips gents.
Found a stainless 5/16-24 bolt at Ace Hardware so will try it out tomorrow.
If it is a 5/16-26 apparently so is the chain adjuster bolt on the 68 Lightning, so I will liberate that temporarily since the Lightning is in drydock.

I expect it will be 5/16"-24 so I suggest you try that first. To check the thread just borrow a 5/16" UNF from the bike if you don't have any.

5/16"-24 it is.
Expected the cam to be keyed in some way?
e.g. I should have marked mount position before removing.
Doh.

The advance unit is keyed on Triumphs, but not on Nortons.
Re-timing is not such a big deal, but remember to wedge the advance unit is out at full advance when you're doing it. There is a special stepped washer to put under the head of the 5/16x24 bolt to do that.
... Gregg

Well, yes, you could have done although easy enough to reset.

http://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf
Section C38,
'Ignition Timing Basic Procedure Prior to Checking'

Cover off and pump out.
Thanks all.