[Exstress]

Once again, thanks for all your advice chaps!!

I will go and do some test starting (but always on a hill) if this rain ever stops. I have a new carb fitted which has been jetted to Sunbeam specification so hopefully the fuel side is ok. I will make sure I have a spare plug with me at all times as well. Which current spark plug does the panel recommend for a 1935 Model 8 please? I have a Champion D16 "Copper Plus" fitted at present.

Regards, John

[VicYouel]

Blimey Rick that is a comprehensive reply!! That stuff on carbs is excellent.

A couple of other points that could be considered.

Firstly I have found that the points do need an occasional  clean up to remove some oxidisation over the winter months.

Secondly I always ride on full advanced.... to retard the ignition when riding or slogging up hills can cause quick overheating and the inevitble consquencies. Always better to change down.

[Rick Parkington]

Hi John,
As Singleminded says, no two bikes are the same; wear and tear has given them all their own, um, personalities, you might say and the need to earn the drill for your bike is part of the bonding process, sort of...
However, firstly, you shouldn't need to tickle a carb when the engine is hot. If you do it suggests that the fuel mixture is too lean in the low range - which most likely means the pilot circuit - or the throttle slide cutaway,given that you probably open the throttle slightly as you kick it over - is at fault.
The ignition lever setting should not be affected by engine temperature and will always need to be retarded slightly to prevent a kick back. If the engine does seem to need more advance when hot it could indicate an ignition problem. Magnetos are internally timed such that the strongest spark occurs at full advance, the spark becoming weaker as you retard the lever. This is no problem with a healthy mag but because magneto problems tend to appear when hot, an engine requiring more advance than usual to start when hot can be a warning that all is not well. if you get a really good spark at full retard with the engine hot, that's good, if not a mag rebuild is on the cards.
But check the points gap - I ran into this one recently. For a mag it should be 0.012". If new points have been fitted the gap tends to close up as they run in and although the engine will run, it can then take an almighty kick to jar them enough to open at kick-over speeds.
Carb wise, weakness in the pilot circuit can, in theory, be addressed by the pilot air screw but if that doesn't help there could be a blockage in the fuel drillings. These are contained within the  brass jet block within the carb body. To remove it you need to undo the large nut on the bottom (remove the float chamber, it's the vase shaped nut the float chamber nut screws into) and then carefully pressing it out - bashing it can distort it. There are some tiny holes that need to be clear. Unfortunately these are the pilot 'jets' so there's no easy way to alter the fuel supply; an air screw should usually be 1.5 to 2.5 turns out fro fully closed, if it's happiest wound fully home it may be you need more fuel but it may also be down to slide/bosy wear allowing too much air in.
If you have removed the choke on the carb,  make sure the hole for the cable is blocked in the carb top or you introduce too much air. 
The slide cutaway is easier to alter, usually engines are happier to start when rich than weak so maybe a lower cutaway would help. The cutaway should be stamped on the top of the slide and is measured in 16ths of an inch so a 4 cutaway is 4/16" or 1/ 4" - that's if you stood the slide on a flat surface and measured up to the apex of the 'arch'.
Realistically a bike should start hot with the throttle completely shut if the pilot is right but throw in an uncertain amount of slide and body wear and the fact that modern fuel isn't the same as the stuff it was made for and it all gets very vague. If your mag passes the hot/full retard test it's likely to be carburetion or technique. Hopefully a bit of practice will sort it out, meanwhile it's good you were able to bump it.   
Cheers Rick

[singleminded]

Ahh, the age old question of starting big singles.
I don't think you will get a definitive answer..My 9A doesn't like to be tickled at all, just turn the fuel on from cold and wait a minute. Turn the engine over a few times and then give a few good kicks.I find that a little advance and a very little bit of throttle and it will start within a few kicks, hot or cold. I usually leave the fuel turned off if I am restarting fairly quickly and the turn it on once the bike is running..My Vincent comet is the same.
A friend of mine has a very nice Raliegh 350 and that likes to be well tickled hot or cold..I'm afraid it is trial and error till you find what you bike likes.OH and always carry a spare spark plug, they sometimes like the plug to be changed if they don't start...John

[Exstress]

Could I ask one further question please.  The mag nut is staying in place and I have had my first run of about 6 miles. I haven't stopped grinning yet!

I did stall on the journey and could not restart the bike with many tries on the kickstart. I ended up with a bump start and then the bike was fine.

What is the procedure for restarting a hot Sunbeam please?  Do I retard the mag fully or leave advanced? Do I re-tickle the carb?
Thanks, John

[Exstress]

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.

[VicYouel]

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

[singleminded]

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

[Exstress]

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

[singleminded]

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

[VicYouel]

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

[Exstress]

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.