Bike running hot - check impeller?

[stay_upright]

After 1 year of no use really my bike did not carburate cleanly (as it did before) and so i have leaned it off to achicve this. Also though it is running hot to the point where it can start to boil over at the top of a tricky hill but when i have not got stuck - this has never happened to me before on a 2 stroke....

So I would like to check the impeller as i've heard it mentioned on here before but what am I looking for? Does a LTR one flow more coolant so keep things cooler?

I did a search for HOT on this forum and the search returned nothing I assume there is a fault with the search function? I can't believe no-one has ever mentioned HOT before in a post...