Successfully started my '99 R1 engine last night (at around 11pm in a, normally, very quiet street!) which was fantastic. Oil pressure seems fine for hot and cold idle and no leaks to report.

Only strange thing was on the initial startup, after about 10 seconds there was a 'bang' sound which was like a fuse blowing (or like those banger things that kids throw). Anyway, started the engine again and everything fine, nice smooth idle and rev'd nicely (just blipped up to 6,000 RPM periodically), no misfiring sound. I thought this might have been the fuel pump seizing and blowing but I tried again this morning and it pumps just fine. The only fuse in the box was the ignition fuse (15A) and this is fine.

Is there anything I should check (like regulator, ECU etc)? COuld it just have been fuel igniting in the exhaust (due to the excess fuel from the first few cranks which didn't fire)?

At a guess it would be the fact that there was a lot of fuel in the engine and some might of gotten into the exhaust and caused it to ignite? As its a carb version that would be my guess