Breakdown.

What was the problem, Peter?

Hi Pete, the failed plug, making your Commando a single the main issue. I have always used the standard Champion plugs in my Commando (NY7C I think) and never had one fail. A lot of hype about fancy plugs when the originals work just fine.

I did, on another bike have a main jet drop into the float bowl, but it was only over about 40mph there was an issue.

You may have one, but there is a special tool to remove / replace main jets in Mk 1 Amals, without having to remove the awkward float bowl.

Hi again Pete, My Commando has been running well on Boyer and standard plugs since 1988. The only issues I ever had was when I changed to a single Mk 1 Carb. Took a while to get that right but eventually got there. But nothing to do with the plugs!

Hi Neil

Do you remember the settings you use for your single Mk1 Amal? I've just adopted the same layout but would be interested to know what Main Jet, Pilot Jet and cutaway you ended up with?

Peter

Hi Pete,

I posted on another message but if your bike is a 750 that will not apply. I wrote down what I remembered but because it has run perfectly this last 5 years, I haven't needed to touch it. The way it should be.

Can't remember if the slide was 3 or 3 1/2? I know, I should have written all this down! Was the stuff I had to change I remembered because I had to pay for the bits...

I strongly recommend you drop John Dunn a line, he is very helpful and will help you best.