Fan swap coolant problem

Yesterday I installed the VTR fan blade. I tried to do it without draining any of the coolant, but I didn’t have a genie, or any pixie dust. I disconnected the lower radiator hose on the left radiator to give myself some extra room. Once I had that off I was able to get the VTR fan blade in there. I wired in a manual override switch for the fan while I was playing around in there. Now here is the problem. I started the bike back up thinking that the system would take coolant from the reservoir and the fan would turn on at the usual 220 deg F. Both assumptions were wrong. The switch will turn the fan on, but it didn’t go on by itself and the coolant reservoir is at the same level before I drained the left radiator. What hell did I do?...

 

You need to purge the system of air, the sensor is at the top of the radiator and the system is reluctant to purge unless revved up several times at operating temperature. You also need to close the gap between the fan and radiator as it will be quite wide unless you "modify" the fan frame. The fan will blow air around the radiator instead of through it unless you close the gap.

 

That makes sense, I took it over to a parking lot afterward, and kept it below 4,000.
Just get it to 180 deg F and rev it up to 9-10K a few times, then watch the resirvior level drop?

Is it as simple as bending the frame inward to get the fan closer? or cut & re-weld?

 

You will see the coolant flow when the thermostat opens by looking down the filler cap and rev the engine, would suggest at least two cycles of the thermostat. If you carefully bend the arms of the frame you can get the desired results with the clearance.

 

That is interesting as I experienced the same issue after removing both rads and then refiling the system. After the first run to 220 deg, I shut it down and the system burped a bunch of air back into the reserve tank. The second run burped but just a tiny bit of air came out. The fan didn't engage on the first run and I was about to start troubleshooting the system but more than likely it was just the result of an air bubble.

We are forcasted to hit ovet 100 deg OAT today! Not a good day for riding in traffic on the VFR, not that mine is ready anyway. Soon baby soon.....

 

Update:

Burped a lot of air out of the system. Fan didnt come on the first time, fan override switch works just fine, but if the fan doesnt come on in the next couple cycles (been rainy all week so I've only been on it once since Sunday) what should I be looking for/ at?

 

Always best proceedure to recheck coolant level after a 20-30 mile ride under the rad cap, not the overflow bottle !!!

There are various reasons why the overflow bottle MAY NOT indicate whether the cooling system is full or isn't, so it's always best to check under the rad cap periodically or after draining.

 

But not when the system is hot!!!!