Help Temperature for the exhaust manifolds

Most likely due to incorrect carb balance.

 

The procedure for your bike is usually detailed in the service manual.
I have never used a gauge. I just use a length of rubber hose placed in the intake of each carb and balance to get the hiss sounding the same. I usually start with a bench balance with the carbs off the bike. Just measure the opening of each butterfly and adjust for them all to be the same. There are various techniques using drill bits and ball bearings. Just do a bit of a google.

In general you start with the carb that connects directly to the throttle cable and the idle adjustment screw. Adjust the idle adjustment screw to get that cylinder (often # 3) sounding ok and the hiss/vacuum at a mild level.
Then go onto the single carb adjacent to that one (#4) and adjust the sync screw between the carbs for the hiss/vacuum to be the same as the previous carb. Now move to the next carb (#2) and adjust its sync screw so its' hiss/vacuum is the same as number 3. Finally adjust #1. You will probably need to wind back the idle adjusting screw as you go to maintain a reasonable (fast) idle speed during the process. Keep going back and forth between the carbs making slight adjustments to the sync screws until they all have similar hiss/vacuum readings. Finally adjust the idle screw back into spec. Check that all carbs are balanced again. Now you should be done. Recheck your exhaust temps after the engine has been running at a fast idle for a few minutes. Hopefully, your exhaust temps will now all be similar. If not recheck your carb balance and if still no good you might need to look for other issues (ignition, valve clearance, compression, etc).
If you have good spark and plugs are ok, then a balance should do the trick.
A correctly balanced engine sounds smooth with no obvious regular beat or throb from a particular cylinder.

Have fun.

 

Balancing the carbs does not typically result in a change to the mixture settings. You are attempting to balance the air flow through each carburettor as the throttle is opened.
A colourtune may help with adjusting the mixture of the carbs, but I have never used one. Best way to set the mixture is on a dyno.