slight overheating problem...

Sup guys
Rite thanks to alot of hard work from me and advice from you guys my mk1 is back on the road!
however im having a small overheating problem…
Its a 1.8 kr on bike carbs, im using a top fill rad and have kept the heater for obvious reasons. I have a huge air con fan from a passat to keep it nice and cool but it keeps getting too hot and throwing a hissy fit!
Head gasket is fine so thats not it, the fan is on a switch so its always on when needed but it jus seems to keep getting too hot
Any ideas what it could be?
Cheers

A little bit of additional information could be helpful here. At this point it could be many things and not really worth guessing. Things like how long does it take to warm up, just when does it begin to overheat, any modifications to the cooling system, does the temp come back down and when/how? Having a switch to operate the fan has always seemed to me to be a "not so great" idea as it only works if you are always watching the gauge and can predict when temps will rise, but that's probibly not the problem.

Do you have a thermostat in the system? Sometimes they stop working..

I can remember something about overheating caused by ignition timing that was off. Maybe do a little search on google about overheating caused by ignition or something can help clarify that…

it get warm almost instantly, no thermostat as we thought it could be this, there isnt much difference on the cooling from standard apart from not running the injection and using carbs so a couple of pipes have been "blanked". Temp comes down a tad when fan kicks in but never really gets "cool". Fans not an issue as i have used fans on a switch before with previous vw's, Any help…

Old rads can "collapse inside" which can almost stop the waterflow.
You say that it gets hot imidiately is a sign that your waterflow is not right.

Do a flush of your system. The other way than the waterpump is directing the water!

Have you removed / checked the thermostat yourself or just been told that it isn't there by a previous owner?

Did you check the timing as i mentioned?

You use terms like "slight overheating" and "warm" in describing the issue. just what are we talking about, overheating or just running a tad bit to warm? Ignition timing or mixture are two simple things that could raise the temperature up a little too much, but that is just a tuning problem. I can't really think of what hoses you could have blanked on a KR that still has a heater hooked up? Just how fast is almost instantly? Are the upper and lower radiator hoses hot? How hot in degrees, or is this based on the factory gauge?