I have. 2004 TXT 280 Pro. Jetting is per recommendations here, fan comes on when it should, running proper coolant, fresh radiator cap. No oil in transmission fluid. I have cleaned and hosed out radiator externals. Running 80:1 using race gas. Problemwas worse with pump gas. Admittedly I ride in San Diego which gets warm, and I do some climbing, but whenever I shut the bike off I can hear the coolant gurgling and boiling. Any ideas?

Wear ear plugs

 

Seriously, any thing with an engine gets warmer when there is no movement of air over it.

 

A cars rad temperature spikes when it is turned off.

 

That is why they used to let the fan run for  a while after the car was turned off.

 

What you are hearing may be normal for that type of bike and ambient temperatures.

 

Try draining the rad fluid and putting a more efficient rad fluid in there such as “Engine Ice”.

 

This should lower the rad  temparature quite a bit.

 

I would assume you checked that the pump was indeed pumping?

Edited September 4, 201510 yr by billyt

  I worked on an 06 Raga 300 the other day that overheated and filled the crankcase full of water, when i went to remove the impeller from the water pump shaft I was suprized how easy it came apart.  It came apart easy brcause there was no impeller just two little pieces of plastic. I've taken many of them apart with stripped threads where the impeller was doing nothing!!

I have a 2015 water pump on the bike - the new design is much better and it's definitely aligned correctly otherwise it wouldn't seal against the engine. It's full of Maxima performance coolant. It has a Kehin carb, maybe I need to adjust the fuel screw as it's running too lean?

Yep impellar

--Biff

It could be your fan is not running fast enough.

You are not losing coolant or seeing steam, right?  You do have enough coolant in the system, right?

 

I agree with others, most likely the impeller has failed. Easy enough to pull it to check.

Lean fuel/air mixture will cause the engine to run hotter.  So will excessive spark advance and long pulls up hill.  Too hot of a plug can also contribute. 

 

I seem to recall a post somewhere by Jim Snell (GG Importer) or Ryan Young (Sherco Importer) that he recommended against using race gas. I don't recall the reason.

 

Check the direction of flow of air from the fan.  I have heard of some people in the southwest reversing it to blow through the radiator to push heat away from the rider.  I amno engineer but I don't think this is a good idea because if you are moving forward at the same speed as the fan is pushing the air, you will get no air flow through the rad.  Hence, not much cooling.

When you fitted the 2015 water pump did you check the system is circulating correctly? Air lock maybe?

 

When the bike is warm, are the bottom hoses as hot as the top hose??

 

If the bike doesn't boil over and throw all the water out of the radiator, then its not really overheating. Is it doing this?

Edited September 4, 201510 yr by faussy

Thank you all so much for the replies! So many great suggestions. I will check the fan speed an that may be the culprit, it is very quiet compared to other bikes and may not be turning fast enough. Will also check feel of cooling hoses and will pull apart impeller. Actually the new style impeller is sealed, I think, so this may not be an option. It is described as an automotive type and may not be serviceable?

Also she does puke out about a half cup if coolant after a long ride. Pretty sure no air lock but I will squeeze the tubes to make sure.

If the bottom hoses are cold while the top hose is hot you have a circulation issue

Edited September 4, 201510 yr by faussy

Head gasket

Head gasket

 

What he said

What he said

 

What they said, Cylinder head inner O-Ring. Pressurizing the cooling system.

So there are telltale signs of coolant dried on the back of the cylinder. Pulled head and it was caked with white crud. The rubber gaskets look fine. But the fan is turning slow enough where I can see the insides of the blades turning. It is pulling hot air out but it's more of a waft. I'm wondering if that means the fan is bad or that it's not getting enough current, any ideas?