Help......Overheating after replacing thermostat, hoses, & cap

Hi everyone, I’m new here. Took a while to be able to join the site. Looks like this site is going to get all the overflow from VFRdiscussion.

What I’m looking for here is some help to know what is normal and what I should do to problem solve this cooling issue.

After I went through a ton of sorting out things with the bike over the winter. One of the things I did was change the all the cooling hoses, thermostat, and cap. This explains the issues I’m having with overheating and wondering if I have blown head gasket.

I took it for a ride to work on the interstate and on the way home it overheated. What I found was about a quart of antifreeze made its way into the reservoir and could not get back out. The cooling system was short about a quart of antifreeze. For good measure I replaced the fan switch as well seeing the fan was not coming on. I also drilled out the clog in the reservoir to help the antifreeze move back and forth, as it should.
Today is my 2nd ride to work and everything has gone well. On the ride home it is going to be about 94 degrees outside air we will see how well she will do.

Welp, it overheated again. For the first 15 miles it was at 176-180. Then all the sudden it says 225-238 as I’m going about 75 mph. It's sit there bouncing all over the place while riding down the interstate. Once I get to the back roads and have to stop it climbs to 252 and starts flashing. By the time I get it to a parking lot to stop it's hitting 270 and not coming down. I stop turn it off the antifreeze is boiling for a minute or so then it dumps a bunch out the reservoir overflow. I wait for it to cool down and limp home with it again getting close to 260 mark. I'm not sure what to do at this point. I followed the manual on filling the coolant and burping it. Is this the best method?

I replaced the switch with a 185f this past weekend.

All the testing I have done at home with letting the bike run until it's hot enough the fan comes on and watch the temp come back down....thinking the cooling system is working. Mean while once I'm on the interstate for 20 miles the temp seems below the fan turning on and then all the sudden there is a demand on cooling the temp spikes and jumps to 220 then bounces around all the while the air flowing through the rads is keep the temps high but below overheating. Once I slow down the temps rise and then they have a hard time coming back down and that's where the temp stays until I turn it off. Then I hear the antifreeze boiling in the system.


My solution is not really a solution it's more of investigation. I need to open the system and run water through it to see if there is a plugged radiator. I doubt it but you never know. If all good there then I'm going to pull the cover off the water pump and take a look at the impeller. At that point I should come up with something that could be the problem.
Would it be safe to say that there is an air bubble in the system somewhere?

Yesterday, I decided to fill the cooling system and run the bike on its side stand to try and get the air out of the coolant system with the cap off. I also watched how the fluid flowed and for bubbles. This whole process leads to the question that this bike runs hot normally does that mean it will overheat if it’s just idling and not moving?

I have no water in the oil, no smoke/steam out the exhaust. After the bike idled for 30 mins in my driveway with the rad cap off burping antifreeze out of the opening where the cap goes. I would add a little antifreeze, but the bike end up getting really hot and overheated. I cut it off as soon as it hit 250 degrees and the fan was not running.

If the thermostat is sticking open would the bike overheat, most likely not? If the thermostat sticking closed would I see the water pump burping antifreeze out the opening as it idled?

I’m planning on pressure testing the cooling system and pulling the plugs to see what they look like. I’m going to have to be totally convinced the head gasket is blown before I tear into that. Looking for ideas, as I have not had this bike long enough to know how it acts and if any of this is normal behavior.

 

Have you checked the air bleed hose from the thermostat housing to the right radiator and the overflow tube from the right rad to the reservoir are correct? Once in a rush to get the bike back together for a trip I crossed them up and ended up with the same symptoms you're having. Got them corrected on the road and problem solved.

 

Hmm, that could be what I did. Great suggestion. I will double check that this weekend.
I hope its something that easy and dumb. thank you!

 

I was not able to do much work this weekend on the bike. Between power outages and things needed done around the house I ran out of time.
What I did get done was, I noticed the hose going to the right rad was connected to the overflow tank. I was able to run water through the system. I am currently working my way down to the thermostat to pull it out and test it along with the old one.
This got me thinking. If I was to pull the thermostat out and ride that way what harm could it do? High idle, yes. Anything else?

 

Overflow tank hose is connected to the nipple at the filler neck or on the radiator body?

 

Yes, that is correct. I was able to verify that much.

 

Well, that's cleared up.

 

No thermostat = slower warm-up, and when running with decent airflow, sub-optimal coolant temperature. I doubt it will affect idle in any way.