As a reference, our pre-09 ran a 124F water temp on a 75 degree day during a road race.  But, we did not have a sensor in the head.  We had it in the hose from the head.  Would expect a sensor in the head to read higher. How much higher I don’t know.

Try putting the sensor in boiling water to test the gauge’s accuracy. Check the radiator cap to see if it’s holding pressure.  I an not fan of the type of pump belts you’re using and would try a conventional belt. If you do go that route, put on extra belts and tie wrap the spares to the center bearing support.  And I’m assuming you are purging the air out of the system before you hit the track.

Another cause could be your chassis set up.  If the chassis is too bound up, that will cause the engine to work harder, causing more heat.  Look at the gear alignment.

Let us know what kind of RPM’s you’re turning. There should be someone on the Forum that’s run with a head temp.  And it might be time to call your local kart shop.

Why do you believe that 160 is too high?  There maybe nothing wrong with your engine.  If there are other Leopards at your track, ask them. We didn’t run a probe in the head of a Leopard but did have one on a Rotax.  150 to the high 160’s were acceptable water temps.  Do not throwing parts at your engine until you’re sure there’s a problem.  A spare pump, belts and gears are good to have as spares.  Unless the gears are severely worn on their sides or the teeth are misshaped, there’s no reason to replace them.  If they are worn, replace them and the chain.  Another good spare for a Leopard would be clutch.

How are you purging the air from the cooling system?  Are you removing the temp sensor and spinning the rear wheels until water comes out?  We used to run the engine on the stand until it started to warm up.  Then would tip the left side of the kart up so the radiator was higher than the engine.  Make sure the pump was turning, set it back down and fill the rad up to the top.  No need to leave room for expansion. The radiator cap is suppose to hold pressure and allow some water to escape if the pressure builds to high. Have a catch can attached to cap.

If the rear width is not at the max allowable, move the hubs out a quarter inch to free the kart up.

See you PM.

Do you have a thermostat installed? 160 is really warm for that kind of ambient temp on a Leopard. Also, have you made sure there is no obstruction in the radiator or cylinder head?

If you don’t have the chassis manual, here is the link.

Adult Setup Guide

You need, to get a thermostat housing in your line headed back to the radiator. Put your sensor in it. Tony is right, it will read different, right at the head. Braided belts work good for me, but I run them straight off the axle, no pully. I think you will see a difference. I do not run a thermostat in warmer weather, only when it starts to get cold.

is your temp sensor between the plug and the head?

if so, that’s probably the reason for the high reading – it’s normal.