valve timing or what?

[Tim]

So I've finally resumed work on the 500 Sei after far too long a time having to do other things. Ive done work on the top end and the engine is back in the frame. The bike has never been running while Ive had it and I'm about to do a belt change. In getting the marks lined up as per the blue book (which they do) I was somewhat surprised by air blowing out through the inlets (valve clearances have been done but maybe I should recheck). Is this valve timing, if so what's the best way to check?
Can someone put my mind at ease...?

[Steve Brown]

When a cylinder is on TDC of its idle stroke both valves will be open. If you find that point and move the piston back and forth around TDC you should see both rockers moving. TDC on compression should have both closed.

[Tim]

Thanks Steve

[Tim]

Well that seems to check out so I’ll soldier on!