Sharky
Well-Known Member
Had this info sent to me....looking for second opinions......
"Yeah, the radiator....as you prolly know, the Max runs pretty hot on a hot day, the rad capacity is right at the limit in the heat.Don’t know if you know this but one of the contributors to the ‘hot’ temps is the fact that the by-pass piping (from the RHS coolant manifold to the thermostat) does not go through the radiator. Even when the thermostat is fully opened the coolant still still flows from the heads to the manifold to the thermo to the pump, by-passing the rad completely.. What Yam should have done is to cool the bypass. The by pass flows around 20% of the pump’s circulation thru the 12mm diam hose, so 20% is uncooled coolant circulating back into the system. If I was getting a rad made I would have this factored into the design or look at increasing the rad capacity.*Todays rad materials have improved a bit from the original Vmax, 25 years ago so that might help.. FWIW. My present scoot is a XVZ 13TF Venture which still uses the same by-pass system but the rad capacity is about double the Vmaxes."
"Yeah, the radiator....as you prolly know, the Max runs pretty hot on a hot day, the rad capacity is right at the limit in the heat.Don’t know if you know this but one of the contributors to the ‘hot’ temps is the fact that the by-pass piping (from the RHS coolant manifold to the thermostat) does not go through the radiator. Even when the thermostat is fully opened the coolant still still flows from the heads to the manifold to the thermo to the pump, by-passing the rad completely.. What Yam should have done is to cool the bypass. The by pass flows around 20% of the pump’s circulation thru the 12mm diam hose, so 20% is uncooled coolant circulating back into the system. If I was getting a rad made I would have this factored into the design or look at increasing the rad capacity.*Todays rad materials have improved a bit from the original Vmax, 25 years ago so that might help.. FWIW. My present scoot is a XVZ 13TF Venture which still uses the same by-pass system but the rad capacity is about double the Vmaxes."