MO1 Magneto Question

[Bob.Murphy]

Folks,

I'm building-up four single cylinder Mags from a collection of bits, and I'm learning a lot. Three of them now work well with "Brightspark" Condensers but I'm still looking for parts as I can't build them all up at the same time .

I acquired a rear cover with the cable entering from the left . . Which means "slack wire for advance" - which would mean I don't have to ride with my thumb between the bar and advance lever any more . I like the idea of this.

BUT (there's always a BUT). When I fit the points face cam it goes a lot deeper into the cover than on the others, there would be room for another locking ring if there was a groove there. The result is that its loose and the nylon rod that works the points isn't long enough.

Do points cams come in different thicknesses, should there be a backing washer or something, what's going on here ??

If I pack it up with a washer it almost clears the peg that limits the Advance/Retard action - which would be bad.

Advice please.

Bob.

[pete.collings]

Hi Bob

I have built and sold a lot of MO1 mags, and know that a few ends had a deeper seating for a thicker camplate. However, the later thinner camplates can be used with a star shaped packing washer underneath, it needs to be star shaped to allow for movement of the camplate plunger. I have never owned such a spacer, although a job lot were sold on EBay recently, selling for more than I was prepared to pay.
I may have a thicker camplate, which I would be happy to swop for your thinner one, as I have more of the later ends.
I have used slack wire advance ends on my VH, but the run of the cable can rub against the barrel and overheat, I just used a spring clamped lightly at the point of contact to avoid this problem.
PM me if you want more details.

Pete

[will_curry]

There are some cable ends which screw into the magneto end cover which are slightly shorter
than the usual ones and which fit quite well as slack-wire cables .There is just enough room
for the flexible part of the cable to clear the barrel fins without strain. These ones I have are
alloy, not steel and if anyone's interested I'll look one out and measure it.

[Bob.Murphy]

Pete,

You have a PM.

Will,

Details are always useful so yes please. Do you know where the shorter cable ends came from (presumably the spring is shorter as well) ??

Thanks for the replies.

Bob.

[will_curry]

That can be the next job up after I've found out why my 500 was such a pig to start and ran
so badly on Sunday. It was fine for the first 35 miles 'til I met up with the rest of the group
at the start. We needed a push in the end - most embarrassing. It's usually a first-kick
starter.

[Bob.Murphy]

My 'VH' was becoming impossible to start without a push -- very embarrasing
Hence the blitz on the Mag .
Bob.

[will_curry]

The fault with mine is carburettor - a duff float needle allowing it to flood slowly and a quantity
of watery sludge in the bottom of the floatbowl and the primary fuel passages. It's a 10 or so year
old 'new' 276 and this is a trick it's only started playing in the last couple of years. The carb was
replaced after an overhaul which included a magneto rebuild. That failed last year when the
slipring disintegrated taking the HT pickup with it. I got home on the metal spring which
should hold the carbon brush. What fun we have, sometimes.

I've found the two cable ends, one measures 27 and a half mm from the thread side of
the hexagon to top, not including the cable adjuster and the other measures just under 24mm
for the same part,

The difference isn't as obvious in the picture as the thread is paradoxically longer on the short
one. I have no idea where the short one came from - I have 3 and I have no idea who gave me two
of them but the third came on the wader on my HT.

[Bob.Murphy]

Interesting. Not a huge difference between them but every little will help.

I thought about putting a short, curved, piece of threaded tubing into the end and putting the adjuster further up the cable. That should direct the cable away from the cylinder fins. A spring around the outer would be a lot less hassle .

Thanks, this is the least of my worries at the moment as I have a lot to do and the date of the LDR is approaching (why do Drags take so long to send stuff . . . And why are items marked "Plenty of Stock" suddenly not available . . its a plot to confound us ).

Bob.

[pete.collings]

Some photos to show the difference between the thicker and thinner MO1 camplates

[Bob.Murphy]

Thanks Pete, I'll PM you again shortly.

Bob.