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Technical Discussion Forum / Re: Magneto sprocket retaining nut. Is Loctite acceptable?
« Last post by Exstress on September 13, 2018, 07:56:59 PM »
Thanks Guys,
This is exactly the sort of advice I was hoping for! That's the great thing about this Forum, you always learn something new after each visit. As a latecomer to the old Sunbeam restoration society I find it invaluable.
John.
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Technical Discussion Forum / Re: Magneto sprocket retaining nut. Is Loctite acceptable?
« Last post by VicYouel on September 13, 2018, 10:17:01 AM »
Hello again,
I don't think putting a spanner on  the small bolt holding the contact breaker assembly is a wise thing to  do by  the way and could cause serious damage to the internals of the magneto. John's advice should be followed.
I usually time at the fully advance setting and leave some tolerance so it is possuble perhaps to very slightly over advance when riding...... best with "tight wire advance".... one must also "approach TDC by turning the back wheel in top gear in the driven direction to allow for any slack. ....hope this makes sense?

It is worth noting that setting the contacts to "just opening" when fully retarded at top dead centre is usually a good way of getting you home when repairing at the road side.
Vic
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If the tapers are good then a sharp tap on the sprocket should hold it tight enough to get the nut tight, good tapers are self locking or virtually self locking. The nut is there to stop vibration from loosening the grip of the taper..There is nothing wrong with using Loctite ( the right grade of course) to stop the nut loosening.
Is the taper on the magneto shaft scored or badly worn? Try tightening the nut with the bike in top gear but with the back brake held on hard to stop the engine turning, it really shouldn't need wrenching up too tight.  John
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Technical Discussion Forum / Re: Magneto sprocket retaining nut. Is Loctite acceptable?
« Last post by Exstress on September 12, 2018, 08:37:04 PM »
Thanks Vic and John.  Please forgive my ignorance as a "newbie" but can you explain in layman's terms how a well fitted taper would stop the nut coming undone.
I wonder if its the way I am tightening it up? I have been setting the timing then getting my wife to hold a socket on the small bolt on the points side whilst I tighten up the sprocket nut.  It will only go so tight before it starts to turn the engine over which I still have in 4th gear from setting the timing.
Should I be doing it a different way or perhaps using 1st gear?  Also, am I correct setting the timing with the mag fully advanced?

Many thanks, John
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i'm with Vic on this problem,especially if only the magneto sprocket nut comes loose. If the bottom one that fits on the inlet cam is fine then the problem must be the taper fit..Personally once I have the magneto sprocket fitting fine I only set the ignition by freeing the bottom sprocket and adjusting from there, I've found it easier..John
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Technical Discussion Forum / Re: Magneto sprocket retaining nut. Is Loctite acceptable?
« Last post by VicYouel on September 12, 2018, 04:36:47 PM »
Somehow I don't think just loctite is the solution....... the magneto sprocket and the cam shaft sprocket are on tapers and care should be taken to gently lap both of them on to the tapers.; it sounds to me as though the magneto one is not lapped on..... if using fine grinding paste you will have to disassemble as you cannot risk any paste migration to delicate parts!
Also wondering whether everything is running true or is some thing eccentric?
Vic
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Technical Discussion Forum / Magneto sprocket retaining nut. Is Loctite acceptable?
« Last post by Exstress on September 12, 2018, 02:24:36 PM »
Hello, I have finally got my 1935 Model 8 running and hoped for a pre winter spin.
Everytime I set the timing the engine runs great for 3 minutes then the magneto sprocket nut becomes loose. the engine retards and overheats then cuts out.

 Is it ok to use Loctite on the nut or is there a special locking washer that should be there but isn't?
Any help on this is appreciated.

John.
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Parts Wanted / Re: Clutch pressure plate
« Last post by singleminded on September 10, 2018, 12:06:55 PM »
I have added a photo in the general section of the gallery of the dome welded back on, it will not last as the metal has worn very thin..John
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Technical Discussion Forum / Re: Clutch pressure plate uneven lift
« Last post by singleminded on September 10, 2018, 11:55:21 AM »
I looked at the clutch plate and found that a 3 degree misalignment between the centre bearing face and the outer part of the plate that bears on the top friction plate gave me 80 thou difference low to high,about 2mm.
I thought about how to check this on the bike and came up with the following which I knocked up out of scraps.
I found that the clutch was completely free at 70thou lift..
Larger photos are in the gallery under the general section.John
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