OK, can someone answer me this...
Why use the KX250F/450F radiators in the first place? Why not use the original KX500 (or whatever donor engine) instead? Is there a significant cooling advantage that I'm not seeing or what?
Look at this diagram I pulled from Benny's build manual...
In my opinion, the factory KX500 routing should be more efficient than the "F" routing as it forces coolant to travel through both radiators. The lower right radiator feeds the water pump then the lower left radiator is fed the hot coolant. From there it has to travel upward through the left radiator, out the balance/transfer hose at the top to the right radiator, then down through the right radiator until it feeds the water pump again. That uses every bit of cooling area provided by both radiators.
Now, notice how the "F" cooling system routes the radiators. Both radiators feed the pump and they both receive the hot coolant from the engine simultaneously and, in theory, should be equal between the two. However, that isn't how things always work in the real world. We all know that all forces (electricity, water, ect.) will take the path of least resistance. I would be willing to bet one radiator does most of the cooling thereby not getting the maximum efficiency from each radiator. The only thing I can see as an advantage to the "F" type routing is if you are low on coolant. If you have at least some coolant in the system then it will be most likely fed back to the engine. Maybe that is needed on a 4T but we are talking about installing 2T engines here.
I know, I'm probably way over thinking it but it just seems logical that the KX500's system of forcing the coolant through both radiators would be superior. I'm sure it probably isn't a big deal either way but with all the headaches associated with modifying the "F" radiators it might be the better option! Thoughts?
