Guys, my bike has been of the road for a couple of weeks whilst I identified an electrical fault. This is now sorted and the bike running again, however I noticed there is some play on the crank when I was removing the fly wheel. Now it's running it smokes a lot when I open it up (apparently it smells like gear oil burning), it doesn't seem to want to fully rev and the revs seem to take a while to drop. I'm assuming the main bearings and crank seals have gone?? Thoughts?

Yep, should be zero play in crank.

Thought as much. Would it be terminal to leave it? Also does the engine have to be split to change the crank seals?

As for it not revving out, is this more likely to be the jets and the bike starving of fuel?

The crank oilseal should be changed without splitting the cases but if you excess end float it may be the mains If the drive side seal is worn then it will draw in gear oil and air making it run weak I would also change the water pump seal when I was in there Got your E mail but cannot open up the link to reply but did send one through the member part of the site