[redyaris]

...ferther to the problems of the VT500 V-twin; the rear cylinder is inadequitly cooled because it is shielded by the front cylinder, the solution Honda uses is to put a larger main jet in the rear cylinder carb [Honda VT 500 front #112, rear #122] this reduces the heat generated by the rear cylinder [cheep and effective]. the normal main jet size for a 250cc cylinder is #110 [Honda CB250].
So by improving the cooling of the rear cylinder the main jet can be reduced to #112 the same as the front. This will also improve fuel econonomy. may even be able to go to #110 main jets.
The way I plan to improve the rear cylinder cooling is with a small 1.9 watt fan [solar powered] aimed at the rear cylinder & head, from the side. This may work well because the cylinder and head are fined, just like an air cooled engine! In fact when at the Honda dealer I looked at the new V-twins; they are all fined like an air cooled engine even though they are liquid cooled?! With this set of modifications I may be able to get into the 80 -90 mpg range consistantly, and no poor/marginal cooling isseus...