[wessex_man]

Personally I prefer the 3/4 long reach, and agree with the article in last Beaming. Better flame propargation, especially when using a more sporting setup.

[hennie.nijhuis]

The Long reach 18mm plugs are like rocking horse manure....

[Ken the Sec]

Was that just because they don't have any long reach plugs in stock?

I have tried both in my Lion 600 and so far can see little difference in performance.  I was hoping the long reach plug might improve the tickover that is sometimes a little difficult to tune.

[hennie.nijhuis]

According to an engineer of the green spark plug company Sunbeam supplied the Model 9 engine with a Champion D9 18mm 1/2 inch reach spark plug

reason beeing that the shorter plug in a longer 3/4 hole would prevent fouling of the plug....

feel free to react on this.

greetings, Hennie