A Fizzy? As in a FS1E Yamaha? Surely that had an expansion chamber on it...

Got these if you can use them...

Welcome! And some very nice work there, glad to see another SJ saved from the scrap heap. If you get stuck you are in the right place, just ask

Barf bag please...

Been scratching my head over this. I take it you've checked under the bonnet and nothing is loose. Have you had a look underneath? Are you sure it's coming from the engine? Sound can be deceptive...can you get a mate to walk behind and in front of the zook while you trundle along and see if they can...

A stab in the dark here but is the cam on that beastie chain driven? That might be the problem.

Most of my tools are Halfords and not had a single one go wrong...good stuff.

Could be one or more things...are the wheels balanced? Wheel nuts all torqued down? Pads shot? Discs knackered? Is the steering wheel bolted down tight?

Could be lots of other reasons but I'd check those first.

Glad it was listed in the bar...I need a drink after that...

Other things wear out as well as engines...I think it could be genuine mileage.