Loss of coolant through tank line, bubbling coolant, where to start

Good day.

84 vf750f.
Last fall, I had the cams reconfigured and tappets cleaned up. Put it all together with a new head gasket and as many as I could get to.

Finally got around to working on the balance and mixtures. I let it idle for about 20 minutes to warm up properly. While working on one carb, it suddenly lost coolant from the belly. I shut off, looked for obvious signs then topped the bottle with clean water and started again. After a few minutes, loosing coolant again but this time more water than coolant (so directly from the bottle, not block or other hose, fitting).

I shut it off, checked the bleed valve in the thermo housing for flow by cranking and letting it run for a few seconds and flow was good. Same thing for upper hose at thermostat so I believe the thermostat is not stuck closed.

I started the bike again and after a few minutes, the fans kicked in and temp did go down. Once they shut off, the temp did not shoot up abnormally.

I let it idle and then shut it off, seeing no more loss of coolant but I did hear a bubbling from the expansion tank and heard some sucking sounds.

There is a chance that I had air trapped in the system but I figure that would cause coolant levels to drop as the air escaped and fluids sucked in. Being that air compresses and fluid does not, I am hoping that not burping the system was the issue. Am I wrong?
I may have also topped the bottle up over the max line....I am not certain, although I am sure I did after the first loss of fluids.

Where to look? I am hoping there isn't an issue with the head gaskets... improper torque causing a leak.
If that is the case, is the headgasket toast or can resetting (not loosening but making sure the bolts aren't loose) the torque be any use?

I'm not sure where to go from here but another head gasket job will kill this bike for me.

I hope my explanation is clear and thank you for any advice.

 

The expansion tank should be at the MIN mark when cold. If you had it filled at MAX or higher when cold, then when the radiator cap let some pressure off (and coolant) to the tank, it likely overfilled and went out the over fill spigot to the ground.

When cold check your radiator level and put your expansion tank at MIN and run again, letting the fans cycle.

You will hear burbling when the radiator is pulling fluid back from the expansion tank and normalizing.

Did you install a new radiator cap? If not, you ABSOLUTELY should. It is key to the system operating correctly and not overheating.

 

Thank you. Will do. Ride safe.

 

I would check your oil if you think it is a head gasket. I have had two rad caps go bad and the symptoms were varied, but all cured by the cap itself. Usually takes me a couple test rides to get the coolant just right.

 

Ummmm, check your rad cap.