Overheat problem

I have been road testing a new to me silverwing 600 spliced onto a Kandi Viper 250 to make a reverse trike. I occasionally have overheat problems after a 25mi round trip. After 12 miles temps seems normal, 3 bars. When I continue to rreturn home it has overheated 2x just before pulling into my driveway. It may just be air in the system after the drain and refill, it sucked down reservoir after the 2 trips, just did a 3rd trip no overheat, 3 bars. I have ordered a new thermostat and cap in case the thermostat is sticking. The fan is working fine. My current question is what is the impeller of the water pump made of, Steel or rubber and do they wear out/deteriorate? No leaks that I have found. I will do a flush and fill when I get the new thermostat.

Just a routine question since these are getting older and rubber dries out (can’t answer what the impeller is made of but I would assume metal)- any chance the return line from the overflow tank to the radiator is leaking and you’re running low on coolant (or the line that goes to the overflow tank)? A new cap is a good idea as well as the spring and seal of the cap may become less reliable over time (had this happen in a car I own and a new cap fixed it from loosing coolant). If the coolant level is low, then it may be escaping via the cap or the overflow line- did it truly overheat or just ran hot on the dash gauge? Fan working fine means it will turn on with the engine hot and bike still (no air movement at the radiator and kicking on properly)?

Hi terryweasely.
1stly, pictures please!

Couple of questions.
Does the trike use the Swing radiator in its original Swing chassis position, if yes, I would say it's probably not getting enough air flow because the seats and central console must be really close masking the air flow.(I had a small plastic bag partly cover my radiator while out riding, didn't take long to come close to overheating, until I found the bag) meaning, the rad needs good airflow, and your in Florida temps.

If it uses a different rad and location how much more piping has been added, also is the rad plumbed the right way around, as in heated output from pump goes to the top of the rad, not the bottom.

awaiting your reply.

Be safe, be seen!

I see no visible leaks around the cap or the tube. It sucks water back into the radiator as it cools down. I have ordered a new cap and thermostat just in case. The gauge on this afternoon's ride was at the top but the idiot light had not come on yet. Top of radiator tank measured 220 deg and bottom of core 178. It is using the original swing radiator and original mounting position. In this configuration the radiator is tilted forward with top about 3 inches from the back of seat area and the bottom below the floor about 4 inches. When moving it should be getting enough air. There are side ducts pushing air into the area behind the seat and to the engine area. When I get the thermostat I will do a system flush and as I replace it along with the cap. My bigger concern right now is that it might be a head gasket problem due to not seeing any water leaking anywhere but getting sucked in after it cools. I have the Kandi trike radiator that actually mounted in back of the right duct but do not know its condition. I had removed it to get better air flow.

Here is a photo of the radiator to back of seats

If the head gasket was failing, wouldn’t you expect coolant loss as well as some white smoke from the coolant getting steamed in the cylinders? Meaning if the coolant level is consistently normal, a head gasket wouldn’t be suspect, would it?

My take---when you are using things not for what they were designed for....you have trouble.

If you have a head gasket issue the engine will run poorly for the first minute or so after a cold start. As the engine cools the pressure in the rad is greater than pressure in the cylinders . On initial startup there would be coolant on top of the pistons causing it to misfire as it tries to burn the coolant

I did a cooling system flush, replaced the thermostat and cap. Went for a 25 mile test drive and all temps stayed normal. I believe it was the thermostat. I did NOT test the old one. As to possible head gasket and water disappearing from reservoir I was overfilling the reservoir. It holding at normal levels now. Thanks to all for help and comments.