Hi Folks
I've got a '98 with about 44K on it. I was out riding the hills in warm weather and discovered my temp guage was nearly pegged. I safely made it home. I'm suspecting the thermostat which has never been replaced, but I'm wondering if there's another common problem at work. Anyone have this experience? Tips are appreciated.

 

Yep...I've got this problem at the moment!
Firstly, can I state the obvious?
Have you checked your Radiator fluid & oil level?
The next possibility causing overheating is the Radiator cap pressure valve sticking..(this has to be checked by a dealer, unless you know someone with a S'hawk that is preparred to lend you one to check if this fixes the problem....
The next possibility is that your bike is running really lean. Have you got a new aftermarket pipe on?

Lastly..(& this is where I am), you will have to remove the thermostat.
Hang it in a pot of cold water with a thermometer next to it & raise the level of the water until it hits 90 degrees F. At this stage the thermostat should open. If it doesn't, it is not allowing water to pass through the radiators & motor & will need to be replaced!

Hope this helps.... :P

 

Excellent, thanks for the info on checking the thermostat - I hadn't thought of that. As the for the other checks - yeah, that all looks good, except I haven't checked the radiator cap. I don't see how that would lead to overheating though.

I was thinking maybe there was a common problem with the fan or electrical system for the fans. I'll check the thermostat first.

 

Thermostat, Cap, Fan or fan thermocouple, or coolant leak.

It's most likely to be the thermostat or cap. The cap is rated 16-20 lbs. Any auto parts store cap of 16 or 18 lb cap that is the same size will work. I understand one for a Toyota fits perfectly.

The thermostat opens at about 165 degrees and is fully open at 194. You can test it in a pot of boiling water with a thermometer.

 

How does the cap affect overheating?

 

Coolant boils at a lower temp when its not under pressure. If the cap won't hold pressure, the coolant expands and comes out the overflow.

I'm actually betting on the cap.

 

Ahhh, thanks Jim!
Is there any way to test the cap? I suppose replacing it is cheap enough. So what do you do, take the cap down to auto parts store and see what matches? I imagine Honda charge four times more.

 

Another thing to check. This happened to me last year. Temp rocketed to 245 degrees. No fan. Made it home. Checked the fuses. Fuse went. Replaced and back to normal.

Only other time this happened was when a rock got caught in the fan, jamming the fan. Extracted and temps back to normal.

 

Hey! This happened to me too!

Opps! attachments post in reverse order.
I'll have to remember that.

~Jeffers

 

Good information - thanks for the tips!

 

Replacing it is cheaper than the labor to have it tested. And yes, take it down there and match it to a car cap.

 

I just finished taking out my thermostat & boiled the sucker in a pot to see if it works & it does.
I'm down to the final thing it could be, & the most expensive fix.. The water pump is RS! Either the pump impeller bearing is seized or there is a leak in the seal there somewhere, but it means draining the oil, removing the water pump & clutch housing & minimum replacing the gaskets & O rings!

 

Huh, that's a drag.
So you checked the radiator cap and the fan fuse?
I hope it's simpler than taking out the water pump, though I believe you can get that out without taking off the clutch cover - it has a separate cover.

 

Yeah mate.....everything else is sweet & works as it should. You can get to the impeller without taking off the clutch housing, but you can't get to the pumpdrive chain & gears without taking it off...!

 

Turns out mine was just the fuse.

 

Hey Mono, if you want to do the w/pump bearing and oil seal, that can only be done with the clutch housing removed, as they fit from the inside.

Also to do the mechanical seal requires removal of the impellor, and guess what, that needs to be knocked out from the inside, so you need to take that cover off mate.......

I did mine two days ago, so if you need any info PM me on OSFS.

Cheers
Shayne

 

Thanks shayno.... You mentioned on the OZFS site that you think it may be simply the fact that I am running a full fairing causing the excessive heat!
This has crossed my mind as well...(& Id love to hear from someone with a full fairing on their Superhawk/Firestorm with a similar problem).
You mentioned fitting a larger oil cooler & I didn't consider this option. What pumps the oil thru the bike? Is it a pump similar to the water, or is it the motor? If it is a pump like the Water, would I have to increase its size to compensate for a larger oil cooler?

Anybody else fitted a larger oil cooler to their bike & if so, off what model? Would it be possible to fit 2 VTR coolers in series?

 

Not only are you running a full fairing, but being a Mario Nava unit it is different than just fitting a lower like most people do. It's design may be a factor.

The oil pump operates the same as the water pump in theory, in that they are both chain driven from the crank, and use an impellor for distribution.
They look completely different though. The oil pump is inside the engine cases and can be accessed after removal of the sump.

I have not heard of any cooling issues with the VTR, and would suspect the cooling system first as you have done. Once this is verified as all good then I would consider the oil cooler. This will be good insurance for you when you do you engine mods. More bang will mean more heat.

My initial thought is that the oil pump will not require any modification to fit a bigger cooler. Volume and pressure should be ok, however there are a number of things to consider. I would seek expert opinion on this. Jamie Bezzina at S&R Pro may be able to assist you here.

I would think that a larger cooler would have a significant effect on the engine temp. Most people overlook the cooling function of the oil in an engine, however it plays an important role in conjunction with the cooling system.

I will post this on OSFS as well.

 

Thanks for the tip shayne...I know Jamie from S&R so I might contact him about the mod!

Cheers mate