Ride-ability upgrades for an Atlas 750

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Rohan said:
[quote="Bernhard"
No, the brand new cam ring which I purchased from Lucas was found to be 4.5 degrees out on the lobes, so i no longer take anything for granted.
You don't have to '' stone '' the cam ring to correct the timing to fire 0 and 180 degrees.
Lucas are making new parts ??
This was recently, or back in history ?

If the lobes are not 180 (magneto) degrees apart, there is no other way to get correct timing....[/quote]

As it is Christmas…….Oh Yes There Is!
Stoning is for wimps :mrgreen: :mrgreen: ………..you obviously have not discovered the ‘’method’’ ….yet.
I was shown this by the late Jack Cooper of Greenwich who along with his brother used to sprint/drag race Triumph twins way back in the 1960s/70s.
I won’t tell you ‘How to’ just yet ……………but...............watch this space.
 
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Here’s how Jack Cooper corrected my magneto which was 20 degrees out.
Obtain some magneto bearing packing shims which (was) available in .003 and .005 thou thickness, cut of into quarters and insert the correct amount, obtained by trial & error, in to one corner- which will lift one cam lobe onto the contact breaker fibre face. check with a timing disc to see if correct amount of shims are inserted.
 
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One corner of what - the bearing race ? Or the end housing ?
This sounds like a bodge at best. (We are talking K2F's here ?).

A good magneto rewinder will fix all the various things that wear, and give you back a good working instrument that should be good for a few decades of happy motoring. Don't forget to keep the points clean and gapped....
 
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Rohan said:
One corner of what - the bearing race ? Or the end housing ?
This sounds like a bodge at best. (We are talking K2F's here ?).

A good magneto rewinder will fix all the various things that wear, and give you back a good working instrument that should be good for a few decades of happy motoring. Don't forget to keep the points clean and gapped....

The explanation is self explanatory. You insert into the corner of the cam holder where the shims would normally go.
It is a matter of suck it and see, until you get the timing correct at 0 and 180 degrees.
You really need to mount the degree disc onto a specially made adaptor to hold the disc on the tapered shaft of the magneto where the drive normally goes; you could have one knocked up on a lathe in an afternoon.
If you really think this is a bodge up, you are entitled to your opinion, the old Lucas factory were churning out magneto parts on old worn out machines that were inaccurate, if my experience is anything to go by when I purchased a new Lucas K2F cam ring, which was 4.5 degrees out between the two lobes, they were guilty of churning out junk that should have ended up in the reject bin if they where inspected, besides a magneto bearing is way cheaper to replace than a chewed up piston caused be inaccurate ignition timing----- don’t ask me how I know.
 
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Bernhard said:
The expiation is self explanatory. .
Call me thick, but I don't even know what an expiation is ?
And still don't see how shims on one corner of a worn timing ring cam can alter the timing towards an even firing maggie ?. That would tilt the timing ring, is that good ? Wouldn't the fibre heel then wear quickly and unevenly ?

Think I much prefer lightly grinding the cam, can see exactly what is going on and where things should be happening. And how they should have been in the first place ? .... Cheers.
 
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Put your fears to one side for a moment, I have found 2 magnetos that where done exactly the same way-besides it works!
 
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