Hot weather starting issues

Hi all,
I have a 2001 CB500S which I love however the last week it refused to start after work so I left it over night then in the morning started first press. Been fine for a few days, started fine this morning but when I've tried it just now it won't fire. It must be to do with the hot weather, have tried some of the quick start spray and that won't do it either.
Have tried no choke, lots of choke and every variation in between - nothing. Help!
Pretty sure battery is ok and it's turning over fine but doesn't even cough.
Thanks in anticipation of your help
Squiffyliffy

Are you sayin it (non start) only happens after it's been sitting in the sun for a few hours? When you say "this last week", do you mean every day?? When the bike is running, is it going ok?
Hard or non starts on a hot engine can indicate valves/compression issue or overheating coils but if a bike is just sittin takin the sun I can't see these being the cause. May sound daft but can you find a cool shaded spot to park in daytime to see if it makes any difference before tearing into things?
Sounds more like an intermittent fuel or electrical/spark problem to me altho, admittedly, if there is a pattern to it as you seem to be saying, it just seems to be too much of a coincidence.
Start with the simple things first. Check if fuel is getting to the carbs in case of any blockages in fuel line or filter; pull the fuel line and blow it through. Check condition of the air filter. Open the fuel cap and if it starts this will tell you if the breather pipe is blocked. If all that checks out then pull the plugs and check the spark and see what the plugs are like, rich, lean or whatever. 
Let us know.

If you've tried "quick start" and it doesn't work then the problem isn't fuel. If the bike runs ok when you do get it running, then it's unlikely to be a mechanical issue. I'd be looking at ignition/electrical systems as a first stop; plugs, coils, wiring connections.

Thanks for the info so far. It's definitely temperature related somehow, the saga goes:
- Monday, rode to/from work fine
- Tuesday, rode to work fine, refused to start at 5pm so got a lift home
- Wednesday, got to work 07:30, started fine. Started 5pm and rode home.
- Thursday rode to/from work fine
- Friday rode to work fine, bit of coughing and spluttering 15:30 but got started and got home
- Saturday, rode to work fine. Wouldn't start 4pm.
- Today, got a lift to work 07:00 started fine and just rode home!
Will try parking in the sheltered bike shed tomorrow to see if that helps.
It's just really annoying since I don't know when/if it's going to do it and now it's working again it's hard to find the fault.
Thanks

Coil pack breaking down would be my first guess, from the symptoms you describe.

Well since posting I've been parking in the sheltered bike shed and haven't had any more problems, has been started fine!
Had a good look round yesterday and found a big split in one of the breather hoses by the carbs and some whiteish gunk (looks like Vaseline so think it's congealed petrol) in another hose.
Going to replace the damaged hose and service the carbs, have had the bike nearly 6 years and never serviced them so they're probably due a bit of TLC anyway.
I hate these intermittent problems!

That hose (I suspect) is the one that goes from the back of the valve cover to the airbox, it would be better if it didn't have a split in it, so, yes, replace it.

The gunk will go away if you get the bike hot enough/ride it for long enough, I suspect.