Some hints on Sunbeams

I think we can all benefit from some of the great advice given to my brother by Archie Beggs as an introduction to the joys of vintage Sunbeam ownership:

“To start from cold, flood carb fully, set ignition halfway advanced (some bikes need more). Do not kick it on the stand (these are a bit fragile).

Put bike in bottom gear and wind it back on compression. Then lift the clutch lever fully at the same time pulling back, whereupon you will feel the clutch plates “unstick”.

Select neutral give slight throttle and swing the kickstart smartly but not a vicious kick and if the bike is in good condition it should start.

When started, check the tell-tale is about 1/4″out showing the oil is getting there. This is vital if taps or anti wet-sumping valves have been fitted.

Before putting the bike in gear pause a moment with clutch fully lifted in order to allow the clutch stop (if one is fitted) to slow the clutch to stop and ensure a silent bottom gear engagement without scrunching the gears.

Refrain from being brutal with the gear lever as on the flat tank models the pivot is riveted and soldered to the tank bottom and may be forced loose and cause leaks. Re-soldering the bracket is very difficult as the deposit from the petrol cannot be accessed for cleaning and the solder will not take.

With the cork clutch the plates run oily and I find auto transmission fluid to be suitable, excess slipping causes overheating and severe clutch drag, so get neutral if you are waiting in traffic.

When adjusting clutch, first ensure the lever on the bridge comes right back (cable not tight) so full travel is attained. Then see that the pushrod is free not end loaded and holding the pressure off

When fitting new plates, particularly if Ferodo, be sure that they are wide enough and do not “bottom” on the end of the gearbox mainshaft.

Oil the valve stems before use and put a teaspoonsful of oil to each gallon of petrol to oil the stems

I use the old KLG M80 for normal running and M100 for “blinding” so source modern equivalent but not ones with internal gaps or resistors.

Check tappets when the engine is really hot and make sure there is a couple of thou’ play by feel not the gauge.

Check the three rear wheel bolts after each run and also the stand bolts.

Drain fuel if the bike is left for more than a week and filter before refilling. When drained put a bit of oil in the tank to deter rust,

Do not start the bike in the workshop but in the open and if you start indoors locate fire extinguisher first. Particularly this applies to vintage Rudges.

Use the soft black linings for front brake -this works.

Check gearbox sprocket occasionally

I have always preferred to drain my oil tank when the bike is in only occasional use using a 1/4″ bore plastic pipe and syphoning it out while hot into a large plastic bottle. While this is messy and a nuisance to do, a look at the bottom of the bottle after it has settled for days may convince you it was worth the trouble and as a result all my oil tanks are clean and do not have an 1/8″ of sludge in the bottom. And the engines last longer.

To adjust clutch stop, slack it off fully then lift clutch, then screw it in till you feel the handlebar lever begin to respond to the pressure and try to lift.

Spark plug gap 16 to 20 thou’ not greater

Sunbeam oil regulator orifice sizes

No 1 .046”, 3/64”, No. drill 56

No 2 .060”, 1/16”, No. drill 53

No 3 .077”, 5/64”, No. drill 47

These are the nearest sizes that I can give.”

 

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