spark plugs

[Tom Gaynor]

I've only ever seen V electrodes in hard grades (I have lots of B10EV's, as used in TZ Yamahas) and my NGK literature describes V and GV variants as racing plugs, which implies grades 8 and above. I've never seen B6EV plugs, which doesn't mean they don't make them. Must take a look tomorrow, but I think Suzuki T20's might have used a B77EV plug. And I do know that in 2001 NGK consigned the B6V to obsolescence.

I did notice that the suffix R indicates the dreaded resistor plug, aka mag-bane, fatal to magnetos, but Z is an "inductive resistance" plug. Anyone know WTF that means? Because I'm running BP6EZ in the (magneto) twin, which starts instantly. I'd hate to think I was slowly killing my mag.

 

[Comet Rider]

Hi Tom,
You can get a BP6EVX, which is what I currently have in my Comet.
On initial observations the tickover was much smoother and also easier starting.

Neil

 

[Simon Dinsdale]

John,
You are nearly correct, except for the polarity. You should have a negative going voltage on the center electrode and the earth electrode should be positive in regards to the center electrode. This is because the center electrode will then be the cathode and as electrons travel from negative cathode to positive anode (earth electrode) and so material will be removed from the center electrode to the earth electrode in the direction of electron flow. Making the center electrode out precious metal reduces this effect. This is why ignition coils have input polarities to ensure the outgoing polarity is negative. Please note this is independent to the polarity of the rest of the bikes electrics.

Cheers,
Simon.

 

[Tom Gaynor]

Last year at Chimay I had problems with my PVL ignition system on the Manx so fitted the newly overhauled 2MTT, which misfired badly. So I borrowed another mag, and all was well. It was only once I was home, having had both PVL and 2MTT checked out as perfect, that I realised what I'd done. I didn't change the R00456-10 surface discharge plug when I changed to the 2MTT. I did change the plug to a conventional thin-wire NGK R17-10, when I fitted the last mag. So I can confirm what John says: surface discharge plugs and magnetos don't play well together. And 10 mm surface discharge plugs cost £35 each...

 

[Graham Smith]

test test test

test test test

 

[John Appleton]

John,
You are nearly correct, except for the polarity,
Simon.

Oooops. caught out!! Simon, at least you were gentle with me. I have often been totally wrong, but this is the first time I have ever been "nearly correct". (actually I was sticking with conventional current flow so as not to confuse all those people who are now confused)

Regards, John

P.S. we have just ordered some BP6ES Iridium plugs, and will no doubt report in due course

 

[Alan J]

After reading all this lot-I'll leave me "vin" in the garage and walk every where!! I have fitted some new plugs at great expense and it is starting better!-N.G.K.s of course-grade 6 this time instead of 7.

 

[Peter Holmes]

Just put in some new Bosch W8CC spark plugs (made in Germany) The Bosch book at my local motor factor lists them as correct for the Vincent, it started first time. Now the bad news, my faithfull Miller dynamo and J G regulator is not showing a charge, it was when put into hibernation last year, I have checked the brushes and they are not worn out or stuck and the comm is clean, any suggestions for a quick fix?

 

[John Appleton]

any suggestions for a quick fix?

Peter, fit a walkernator.
John

 

[van drenth]

You have to flash-up your generator'
Van Drenth JC