Forum

[Davie Hall]

If you still have the old plug try it back in the bike. Over the years I have had a few faulty plugs. I once managed to have 5 out of 6 champion plugs faulty on a honda cbx6. Champion said they didn't make faulty plugs

[Beezabryan]

Might not have been Champion that made them

[Frank]

Might also be worth checking for an air leak in the exhaust or the blanking plug on the cylinder head exhaust port where the PAV pipe used to go. Might be a leak which seals itself when hot.