Cooling - leak & temp issues.

Hi all… got a problem. I am really trying to make the PGR Mission to Prescott Arizona on behalf of the 19 fallen Heroes on Tuesday.

My 89 has been running hot in our cool 110 degree days. So, I flushed the system and changed all the gaskets and o-rings on the thermostat and the round diverter. Other than it was an absolute PIA, It seemed to button up pretty tight. I did not have a chance to ride it yesterday, but was able to idle it up to running temp. I can’t risk trashing the bike in 110ish degree - 500 mile round trip ride on Tuesday.

This morning I went out to take it for a ride and there was a puddle under the bike. From looking at it, it appeared to be from the radiator area and I thought maybe it was residual from filling the radiator with coolant. The weird part was that the overflow bottle was bone dry. I had filled it half way. I filled it again ½ way.

Rolled the bike outside and hosed off the whole radiator and under carriage area. Took her for a 10 mile ride. The temp seemed to be OK ( ½ way) for most of the ride. (picture) Once I got home it was a little higher than ½ way and after idling for a few minutes it went to the ¾’s area.

But, once I put it on the center stand I noticed that it was puking coolant out of a drain type hose by the rear shock. (picture)

I checked the overflow bottle and it was filled to the top.

I have her cooling down on the center stand and paper under it to see if it drips and from where. Just wondering what you Gurus think.

YES… the diverter thing-a-bob is turned to the correct (?) position with the writing upside down.

I suspect your flushing procedure resulted in an air bubble deep in the engine. Bleeding bubbles out of the cooling system is required on these machines. The air expands with steam forming inside it that pushes coolant up into, and out of the overflow tank, and piddles on the floor via the drain tube. The system is probably air free now on its own. Just check that the overflow tank is at proper fluid level.

One can double check the system by removing the radiator cap (cold) and confirming the radiator is completely full to the top. This check causes fluid to run out of the overflow tank via the tank-radiator hose, so be prepared, or pinch it closed with a clamp. Then refill the overflow tank

-Pete, in Tacoma WA USA

Thanks Peder... sounds like you hit it on the head. Took it on a 13 mile run yesterday morning and no issues upon return. Parked it for 7 hours while away and when I got home no leaks. Checked on it this morning, no leaks. Took her for a short 4 mile spin and parked it.. no leaks.... I am looking like I am on a no leak roll here....

Yup! Air pockets are a PITA to avoid on any vehicle and Peder described them perfectly!