My Valk is overheating....help!

[BigBishop]

Alright Guys.... I have a 99 Valk. It's overheating.... I believe part of the problem is that the fan is not turning on. I changed the radiador fane switch. But still nothing.
Any suggestions? 

[Thunderbolt]

seems like that was the suggested method of checking the fan.

[Bugslayer]

Alright Guys.... I have a 99 Valk. It's overheating.... I believe part of the problem is that the fan is not turning on. I changed the radiador fane switch. But still nothing.
Any suggestions? 

If it's not coming on when you ground the wire, maybe it's a blown fuse..?.. My fan very seldom comes on. Are you sure it's over heating? What's it doing?

[BigBishop]

Yes I grounded the fan and it does come on. So I know that the fan is good.
Weather it's overheating or not is a question I considered myself. What it's doing is: it's spitting fluid out of the cap and it's smoking from the cap. It looks like it's overheating but since a bike normally  get hot I really don't know.
Thoughts? 

[Jackleg]

Sounds like your radiator cap is loose. Have you removed it lately And possibly reinstalled it incorrectly?

[BigBishop]

Yes did that.... I may just try buying a new one.

[Robert]

The problem if the thing is overheating is more than likely a bad thermostat. The fan switch will not turn on the fan unless there is hot water in the radiator if the thermostat is closed then there will be no circulation to the radiator and no hot water. It would be nice if you had some way to check engine temp like a temp gun but barring that feel the radiator hoses and the engine. If the radiator hoses are cool or only warm and the engine is hot then you have a thermostat problem. The hoses can be warm but in a properly running engine the top radiator hose should be pretty close to engine temp with the bottom hose only being a little cooler. If this is not the case like the top hose is pretty hot and the bottom is warm to cool then that's the problem. The only other thing that I would suggest is making sure the water pump is circulating water. I reread your post and if you take off the radiator cap and run the bike there should be no water peculating out of the top. This is of course after you open it and get the initial pressure out of the system ,it will run over a little but should not boil out and you should see some kind of circulation in there, kind of a second way just to verify that the thing is indeed running to hot in absence of a gauge.

[Chrisj CMA]

Yes did that.... I may just try buying a new one.

2 things before you replace that cap:

1. if you forced it open without removing the set screw then undoubetly you have buggerd up the tangs on the cap that tighten against the spout of the radiator.  Be careful, think through  and bend back into place

2. check the top surface of the opening and see if its flat, may need a flat file to lightly smoothe it to get a better seal

[MP]

+1 on the ears on the cap.  Bend them a little down.  Put on the cap.  It should be tight.  If ANY wiggle, it is loose.  Refill the radiator with silicate free antifreeze.  Check the bottle under the LH cover.  Just the ears loose can do all you described. Might be a very simple fix.

MP

[Hoser]

Removing the cap without loosening the set screw will really fark things up.  hoser

[Bob E.]

I had a problem where my fan was rubbing the shroud behind the radiator.  This would prevent it from turning, thus blowing the fuse.  I was able to adjust the metal fan shroud with a couple gentle whacks from a hammer...enough to clear the fan blades and this cured the problem.  So as suggested, check you fuse, then reach in behind the radiator and see if you fan will spin freely.

[asfltdncr]

I did precisely that--set screw deal.I ended up trueing the radiator neck surface to stop the spitting.
This would happen well into a ride sometime.Make sure your present cap hasn't got any aluminum material imbedded in the rubber gaskets on the cap itself.PROBABLY not overheating at all.
Good luck and don't file much or more than needed.I don't know the wall thickness of the radiator throat.

[Red Diamond]

The problem if the thing is overheating is more than likely a bad thermostat. The fan switch will not turn on the fan unless there is hot water in the radiator if the thermostat is closed then there will be no circulation to the radiator and no hot water. It would be nice if you had some way to check engine temp like a temp gun but barring that feel the radiator hoses and the engine. If the radiator hoses are cool or only warm and the engine is hot then you have a thermostat problem. The hoses can be warm but in a properly running engine the top radiator hose should be pretty close to engine temp with the bottom hose only being a little cooler. If this is not the case like the top hose is pretty hot and the bottom is warm to cool then that's the problem. The only other thing that I would suggest is making sure the water pump is circulating water. I reread your post and if you take off the radiator cap and run the bike there should be no water peculating out of the top. This is of course after you open it and get the initial pressure out of the system ,it will run over a little but should not boil out and you should see some kind of circulation in there, kind of a second way just to verify that the thing is indeed running to hot in absence of a gauge.

I'll disssagree with you on this one Robert.  If the thermostat is not opening when it should
(at approx. 160-180 degrees) and stays closed, believe me, you won't find anything cool on that engine. Everything gets hot and the fan should kick in if the fan switch is working properly. The purpose of the thermostat is to  control the operating temp of the engine, i.e 190, 200 deg and so on. If the temp is low the thermostat closes, if it is high, it opens and so on.
      I would check, as others have suggested, the radiator cap, the water pump and other related temp items, and first, be sure the bike is running hot. The engine should be touchable even after running a few miles. If it is indeed running hot, the fan should come on, if it does not come on, check related items. Good luck and ride safely. One more thing, the engine need not be running hot for steam and/or water to spew from the radiator cap. That system is under pressure and if the cap is bad, it will let off steam at a lower pressure than it is designed for and also not let off pressure that it is suppose to let it off at. If the fan switch is good, thermostat is working properly, fan works and does not come on when coolant spews out, chances are your bike is not running hot. my .02

[Gryphon Rider]

One big clue that the engine is overheating is that the engine temperature light comes on.  If the rad cap is sealed properly and the engine overheats, it should be venting and boiling into the overflow tank, not out the rad cap.

[Robert]

Diamond, it will more than likely turn out to be the rad cap like many have said. I responded as if it were really overheating because there were already enough posts about the rad cap, and said he really needed to check to confirm of it overheating, but I wanted to give some info that he may not have had including the fact that if the thermostat is stuck closed the fan will not go on, Why? because the fan switch is located in the radiator on the side that the water has already been cooled and the coolant is headed back to the engine. Like you also said its the job of the thermostat is to regulate and is accomplished by restricting flow. The radiator fan switch is meant to switch on at 210 and will never see that temp if there is no flow so the fan will not go on. Yes the hoses will be warm but not hot the engine on the other hand will see temps say 200 to 230 maybe 240. If the fan switch had been located in the engine then the fan would come on. If you doubt this when cold take a ride on your bike and compare engine hose and radiator temp till the thermostat opens you will notice the radiator will be cold and engine hot. If the thermostat is partially open you will see the upper hose hot and lower hose luke warm. Normally the difference in upper to lower radiator hose temps will be about 20 maybe 40 degrees. This will make both hoses feel pretty close on temp. If you have run the engine to the point of overheating you will still be able to tell a temp diff but no where as easily. Steam and boiling will make like you said everything pretty hot ,Thats why you need to start with a engine not run into the red zone and has water in it. Most dont think about the fact of no water circulation as the cause of a fan that doesn't go on and is also one of the simple stumper's that I have seen many mechanics make a mistake on.

[Red Diamond]

Thanks for that info, my opinion was based on my experience with car engines. Since the Valkyrie engine is so close to a car engine, I figured the cooling system should operate the same. That's what I get for figuring. I'll file that info for future reference.

[BigBishop]

Great stuff guys. Thank you! I'm going to work on it today.
Good being apart of this site!
Ride Safe!

[Bugslayer]

Let us know what you figure out.
Good luck. 

[Robert]

Diamond I think I have a thought for you, if you are used to dealing with American cars then the fan would kick in if the thermostat was closed. American cars have the fan switch in the engine block either as a separate switch or as a temp sensor for the computer with the computer turning on the fan. So if the thermostat is closed and the engine starts to overheat then the fan would come on regardless if the water in the radiator were hot or cold. Japs and Europeans do it either way but a good part put it in the radiator then it is as I explained and its how the Valk is set up so that may explain things

[F6Viking]

One other thing to check, if you have done any work in the areas the vent/overflow tube runs to the reservoir, you may have it pinched. Had same problem a few years back. Had done some service work and first time I rode afterwards was to work and by the time I reached work (17 miles) I had anti-freeze blowing all down right side. Got to checking and found tube was pinched and wasn't letting pressure release when it got hot, had no where to go but out around cap. Fixed tube route and no more problems.