Ok so a good few weeks back I started getting some noises from the front sproket. Tony suggested that it was the chain hitting the aftermarket exhaust and guess what... he was dead right. Cheers

but I did also needed to change the chain and sprokets. The front one in particular looked like it had never been changed. Sharp teeth with a visible twist

So got new chain and sprockets changed them and now the bike won't start. Not even a promise of firing. So here's what I did, and I can't think it would have an effect but if anyone knows different then please let me know.
I took the front sproket cover off complete with the clutch cylinder. The pushrod came with it about half way I reckon so I shoved that back in. Cleaned a hell of a lot of crap from around the sprokect changed it over (kept her in gear whilst I undid the bolts and re-torqued). Changed the rear sprokect, installed the chain put the sproket cover complete with clutch cylinder back in place. Had the battery on charge so loads of power. Tried to fire her up and she just isn't interested

. I can hear air being pumped out of the exhausts, so definately turning over. I pulled a plug out and checked the spark and it's sparking no problem. Doesn't look amazingly bright but it was in direct sunlight, so probably stronger than I thought. I can smell a bit of petrol but not that strong. So put the plug back turned her over loads, pumped the choke and then checked the plugs again. Now at this point I would expect a very strong smell of petrol and the plugs to at least be damp but no. Plugs dry as and still not the strong petrol smell. So the logical conclusion is that I have trapped a fuel line somewhere, but I can't find one, and all the work was down by the final drive and no where near the fuel system.
So before I start to strip down the fuel system and start flushing out lines, does anybody have any ideas? or is there a common fuel blockage?
The other thing I noticed when moving the tank around is that there is something rattling around in the tank (sounds substantial like a bolt) and I'm pretty sure I haven't heard that before. Anyway I'm pretty stumped

... to be fair she is a fairly abused storm but normally runs like clockwork, did the RBLR1000 and she didn't miss a beat, three days after this took her to Assen and no problems at all, then used for work etc... up until now the most reliable bike I have ever had and she's been with me since 2004.
All suggestions heartily welcome.
Cheers
Neil