Mine is doing almost the same, but it clears every now and then, or even if you rev it hard to clear it
This had me also thinking it was fuel related ??
I've been using it for work evey day this week and the only time it does it religiously is in the first 30 seconds of riding when cold, after that it's a lottery ??
Guess i'd better stick the old plugs in and take it from there
Dave
