Ariel Owners Motorcycle Club

I have yet to run the engine of my '54 VH500. The magneto produces a good spark when turning over the engine with the kickstart but I am concerned that I will not be able to stop the engine running because earthing the magneto via the earth wire does not stop the spark!

Am I missing something?

The earth wire shows continuity and is in contact with the engine during testing but still I get a spark at the spark plug.
Dennis

Earth wire? Do you mean the magneto body earth? Ariel's don't normally have an earthing end cap...

I use the valve lifter to stop mine.

As simon says there isn't an earthing stop - usually - fitted to the
magdynos usually fitted to singles.

hi i have a new mag cap with a earth switch on my NH and a valve lifter i use the switch to stop the engine being started and to stop it wet sumping when it is left for a long time

Thanks both. I misunderstood what the earth terminal on the magneto is for. I know understand that is to earth the magneto body and not the points. I see that you can buy an end cap that includes a contact to earth the points to stop the spark and hence stop the engine. However, if the original method of stopping the engine is to use the exhaust valve lifter I will do that for now. I will also use the earth terminal to bond the magneto (and dynamo) to the engine and frame.
Dennis

hi dennis i have fitted a earth on the mag to the engine and gearbox plate i found it made it start and runs better i did do , a post about it last year when i was rebuilding my NH

Johnny,

Thanks I plan to do that as well.
Dennis

glad johhny mentioned the earth wire because i have also noted another indicator to a problem that might occur .

when i found that my NH magdyno magneto mounting bolts had become loose i had experienced erratic charging on the ammeter and a slight misfire but only found the mag loose when i happened to put my hand on it to check something else and found it wobbled a bit .

it may help anyone else with a similar charging issue occur to spot a loose magneto mounting .

i now check the magneto for movement regularly and will also put an earthing wire from the mag .

does the earthing wire go to the battery earth via wiring loom or anywhere particular on the frame , i have neg earth system myself .

cheers , ian

My magneto earth is a short (3") wire that goes to the adjacent crankcase stud.

hi i fitted my earth form the mag to the 1/4" bolt on the engine plate that supports the engine that the mag sits on , and i think it looks very neat with the wire running straight down , and not fitted to the engine