TOPIC:

Warming up the carb bodies with a hair dryer will help preheat the intake air and let's face it, the heat from the hair dryer will also heat up the intake tracts as well at the same time. All this heat is helping vaporize the fuel in the intake air to assist with igniting the mixture. The choke circuit is enrichining the fuel mixture to help guarantee ignition while the engine is warming up. Once the engine is warmed up, latent heat from the cylinder head is warming up the intake air and mixture which help vaporize the mixture. This whole reasoning about vaporizing the mixture explains why propane and or natural gas vehicles do not require a choke circuit. The "fuel " is vaporized as supplied.
Another thought that you should consider is that you may have a weak diode in the rectifier/regulator which is discharging the battery while the bike is sitting and maybe the 4 day mark is the "point of no ignition" due to the starting circuit drawing down the voltage enough that the ignition doesn't have enough voltage to fire the bike. I've seen it before where the engine is just turning over and no spark until an additional electrical source (boost battery) is added to raise the voltage up high enough so the ignition fires.

My money goes on the possibility that one or all of the choke circuits in the three carbs is either not operating properly or somehow blocked. If warming up the carbs works after a 4 day layover, then I suspect that it's a fuel problem. Even if the float bowls evaporated some of the fuel , the choke circuit should at least fire the bike then stall out. The choke circuit will pull up fuel from a low float bowl.

I think you're all missing a critical part of this topic. Historically,it seems to be the least discussed..
If the engine runs well otherwise and hard starting is the only problem then one should look closely at the choke/fast idle set-up. In my manual this is detailed on page #50 with 3 photos #E20 - E21 - E22. This is your starting point - no pun intended.
If this initial adjustment isn't correct then hard starting issues will prevail. It's ALL about the relationship between throttle-plate position (vacuum between the throttle-plates and cylinders) and the amount of choke-plunger lift (amount of raw fuel being "dumped" into the intake). If this isn't coordinated correctly then you can have a too lean or too rich situation when trying to start cold and particularly after the bike has sat for a while. ( bowls and fuel galleries dry.)

That's the Short version.

Thank you all for the input it's definitely something I can now look at as I didn't know where to turn next, I didn't think it was my battery as even when hooking a good car one same problem. Just one more question is it wise to get a led front light to save battery drain when starting?

Personally, I wouldn't waste my money on an LED Bulb conversion. The idea of saving some current for the battery's benefit is good in principle but the other concern should be the light output for night riding. A good quality Sealed-beam will give you more light, correctly focused and with far better reliability. Replacing the Halogen bulb with a Hi/Lo LED conversion is purely hit-n-miss. Our typical OEM headlight/reflector is engineered for a Filament light source (Halogen typical) and the unique light dispersal characteristics of this type of bulb. The light source and the reflector must work together for maximum light, pattern and distance. A generic LED conversion bulb is not engineered for a specific headlight body. Additionally, some LED conversions use a separate "driver". In simple terms, a voltage regulator/stabilizer. There could be a problem getting all of this into the headlight bucket.
LED technology has come a long way. But: I recently tried a 12 LED "Driving-light" in place of the 55W halogen driving light I have mounted under the headlight. This LED "Driving- Light" came as a complete unit with it's own housing and reflector/lens. I mounted the two lights side by side and used a car battery as the power source. Wired in parallel with a switch I could select back and forth between the 55w Halogen and the LED, for comparison. The light output of the LED was ok, but still disappointing ! I put the 55W Halogen light back on!
If you're concerned about delivering the most power to the Starter - by being able to turn off the headlight - then you'll need a "Double-Pole/Double Throw" switch so the POWER to both the Hi and Lo can be interrupted simultaneously. With the power to both filaments interrupted, the Headlight warning light will illuminate, reminding you your headlight is OFF. When the switch is flipped to turn the headlight back on, the headlight warning light will go off (provided both filaments are good and you've wired it correctly.)
Better to get the difficult starting issue dealt with; which I often attribute to a carb. set-up issue.

Thank you once again! I've had a quick look and followed the manual, all seems fine apart from when I lift up choke lever fully the roller isn't turning freely, as it does when it's fully down ,should the roller sit in the indent on the choke cam? Also not sure about the adjusting screws job?

The "roller" should roll. That's it's job - To make the mechanism move more smoothly and easily. If it's not rolling then it's either gummed-up which can be dealt with a cleaning and 1 drop of oil. If the roller has been "stuck" for some time then it's possible it's been worn (flattened) and probably won't roll regardless of a cleaning and lube.
The roller will drop into the indent when the choke is full ON. This allows the choke plungers to be fully lifted and the throttle plates to be closed. The roller should not make any contact with the fast idle cam when the choke is OFF. If it does, then it usually is indicated by an inconsistent idle/high idle, regardless of the idle adjustment screw (between the left and center carb's.) The Philips screw that you refer to is to adjust the point when the roller makes contact on the cam, relative to the throttle plate position. It's a critical part of the carb set-up.
NEVER try to "Fix" an idle/choke issue by changing the profile of the fast idle cam.