Right - time to take the B33 for a test run. First problem - the timing moved. Re set and made sure the dizzy bolt was tight this time. Next problem - could feel what seemed like a bearing failing. Found out later it was the rear wheel bearing. It hadn't failed but the locking collar had worked loose. That was fixed too. Next problem - the front pulley on the belt drive is too loose on the splines. This is a fault from manufacture, so it's time to buy an aftermarket pulley and find a place that can broach the splined hole to the correct tolerance. There again, today was the first 100 miles that the bike has covered and none of the problems are insurmountable.