Best way to confirm coolant system is completely bled?

Hey guys,

This is my first post in the 5th gen forum. I just picked up a 98' with ~36k on the clock a couple weeks ago. Long story short it was getting pretty hot, to where I was nervous of hitting 251 while stuck in 20 min of barely moving traffic.

So yesterday I removed the fairings and found no coolant left in the reservoir, so I've got a slow leak somewhere, because I haven't noticed any puddles or drips. Anyways, I took out the old coolant per the FSM, flushed with pure distilled water, and then refilled with Honda HP coolant. The FSM says to let it idle on the center stand for 2-3min with the rad cap off, "Snap the throttle" 3-4 times (I guess revving it to like 10-11k really fast?) to bleed the air. I followed this procedure.

The reason I'm curious because it seems like my fan is coming on and shutting off at different temperatures each time when I'm looking at the coolant temp gauge. Is the fan switch not necessarily seeing the same temp because of an air bubble? Or because the two sensors are at different places in the system?

What is the best way to confirm there is no more air in the system and that it is functioning correctly? If I remove the rad cap now (cold, sitting since last night), should the coolant be up at the filler neck? Thanks in advance!

Best,
Chris

 

AFTER COOL, remove the radiator cap & top off if necessary. Repeat the startup & run procedure with the cap off until warm; top off if necessary. Repeat until you no longer have to top off the radiator. Once you've got the coolant staying at the top of the cap, fill your overflow reservoir to the specified level.

 

I find you get a much better result with the bike on side stand.
Make sure you check the overflow line for a blockage.

 

I have found the best trick is to park the bike facing up hill and on the side stand. The goal is the get the radiator cap opening to be the highest point in the system, so the air can escape. With the engine running, squeeze the coolant hoses to force the coolant and air to move around, eventually working the air out of the system.

Another trick is to, on the initial refill, add the coolant slowly. This allows the air to escape.