Thermostat - VTEC Replacement

[HispanicSlammer]

Craigs bike a 2002 VTEC was constantly spewing antifreeze out of the overflow tube, sometimes onto the rear tire while riding into turns. He reported that twice at our last track day that he slipped from this happening. Our trip to Maroon Bells following him I could see water pouring out of the tube.

He would refill the overflow tank with water at each stop, and the left side radiator was not hot. A sure sign that the thermostat was stuck closed.

Click Here for a large picture with text labels

Craig had already removed the tank and the air-box when I arrived at his house. He moved the tank to the seat and placed it back-wards, unplugging the fuel pump and fuel sensor. He unplugged the Map sensor and removed the vacuum tube, he unplugged the air box temperature sensor and unplugged the two crank case breather tubes. He Removed the air filter and the four velocity stacks, he had the taller ones in the back short ones in the front.

Craig removed the tank and air box

After removing the tow side fairings, on the left side is a hole for you to probe a long screwdriver, it needs a very long Phillips to loosen the clamps on the intakes.

Sticking in the screwdriver to loosen the intake clamps

Shine a light down to see the clamp and loosen it, that cylinder on the left is the wax element.

Loosen the four bottom clamps, this is the left front

Remove the drain plug and screw off the radiator cap to let out all the antifreeze

Gently pull on the fuel rails to lift the throttle body out, be very careful here not to force anything. There are two hoses connected to the wax element that need to be removed, the idle speed cable must be threaded from the right side and allowed to come loose careful not to break it. There are several wires in the throttle body for the fuel injection you can leave them on. We removed them to treat them with dielectric grease to prevent corrosion. Make note of which connectors go where most are unique but the fuel injector connectors can get confused.

You will need to remove the throttle cables by removing the two hex nuts on the throttle cable bracket and then popping the cables from the throttle wheel.

Gently lift the throttle body out carefully not to force anything

I removed the throttle cables and Craig threaded the idle screw cable free, here I am removing the two hoses to the wax element

With the throttle bodies free we unhooked the wire harness and exposed the thermostat housing.

Most of the clamps were facing down so we had to remove the housing from the other side of the hose.

Tape over the intakes so nothing gets inside the engine

Remove the old thermostat, there are two 8 mm bolts to loosen on the bottom and it cracks open like a clam

Craig seats the new thermostat in the housing

The O ring is a bit tricky its larger than the seat it fits into, with little nubs to pinch the ring into place.

We turned all the clamps facing up and fitted all the hoses back on, tightened and re-tightened each one. Then reinstalled the hoses to the wax unit, threaded the idle cable back in place, connected all the electrical connectors, and gently pushed the throttle body into place. With a flash light we inspected the intakes to make sure the rubber boots were seated and began to tighten the clamps.

Gently Craig seats the throttle body back onto the intakes.

I am flashing a light onto the clamps as Craig works the screwdriver onto the clamp screws, they are supposed to be 7mm from nut to bolt tight.

We slid the air box into place connected the temp sensor, the map sensor and the vacuum tube, connected the flapper solenoid and vacuum tube. Craig decided to leave the flapper tube disconnected and stopped it up with a screw in the hose. We replaced the air stacks tall in back and short in front. Replaced the filter, hooked up the crankcase breathers, and screwed on the top. Hooked up the gas pump and tank sensor and put the tank back in place. Filled up the radiator with 50/50 prestone no silica. We started it up - no fuel injector light so the electrical connections were correct, then we let it heat up, I put my hand on the left radiator and at 175 it started to heat up so the thermostat was working.

Then we opened up the radiator cap and filled it all the way, turned on the motor and blipped the throttle until the all the air was burped out of the system. Craig put the cap on and we ran it to full temp all the way to 220 when the fan came on and the temperature leveled out. we watched the level of the overflow tank after filling it to the top line. It stayed at the same level. I think his problems with antifreeze on his rear tire are over.

[VFRMAN]

What parts would I need,or would be good to have at hand just in case along with the new stat, to replace the stat on a 5th gen?

thanks.