Overheating

[Vtwin650]

Well it was a nasty humid 90 degrees this weekend and I went for a sweaty ride.

Stopped at a stoplight the bike heated up - last season i installed an auxillary switch for the electric fan so that I can turn it on whenever I feel the need - not have to wait for the thermostatic switch to hopefully work.

So stopeed at a stoplight, the bike heats up, i flip the fan on and it keeps the heat down for a bit, but the damn street light stays red - there happens to be a cop behind me - or I would have run the light. Now the bike starts to heat up all the wat towards the RED in the guage!!??? So I kill it and wait for the light.

Once I get moving again, the bike cools back down and everything is good. So my question is, could i have a problem with my thermostat or something related? I am just not looking forward to the 100+ degree days this summer worrying about the bike overheating.

Thanks for the help.
Ashton
'89 Red
57000 miles
Fort Worth, TX

[Soul]

Re: Overheating

Well it was a nasty humid 90 degrees this weekend and I went for a sweaty ride.

Jesus..When reading that I thought to myself "does this guy live in hell or something?" its like 50 here..
Are your fluids ok? Everything filled nicely? It does sound like it could be a thermastat problem, if all your fluids are ok.

[bfizzle]

Cooling systems on bikes are designed to work best when you are moving. The electric fan helps some... but just isn't adequate for extended periods. I've been told that is bad to let your bike sit for 10-15 minutes in a garage without having a box fan blowing on it.

Check out the thermostat for sure though.

[Vtwin650]

nope, not hell - TEXAS!

I will buy a new thermostat just to be safe

thanks

[SpeedyR]

the hawk should idle for a long time without any problems if your system is working well...

instead of replacing the thermostat, I'd first check out the radiator cap. in just about all the cases I've looked at (my own as well as friends) it was the radiator cap that was going bad that caused overheating. May not make a lot of sense but it seems that it just doesn't keep enough pressure in the system and it boils over.

now that I think of it though the normal symptom with the bad cap is that it will boil over the fluid (you'll hear it in the overflow tank and it'll come spraying out the tube under the sidestand. Normally this happens right before the needle gets into the red on the temp guage...

anyway just something else to check into before you go replacing everything else.

mine would overheat if sitting for a bit as well as if I was really flogging it on twisty roads at a bit higher elevation when it was hot.

good luck!

Jeff

[Schiff32]

Sorry to bring up a dead thread... but just got my bike a week ago and it overheated already. Yikes!! It was sitting for about 10min. or so, by the time I looked over it was smoking and fluid comming out the bottom. I checked the fluid levels and they seemed ok, I couldn't tell if the fan kicked on or not, it was in the red by the time i ran over to it. I'll try replacing the cap, any suggestions on where to get one or which ones will work? Yeah, I'm a total noob with regard to motorcycles....

[AK_Hawk]

I couldn't tell if the fan kicked on or not, it was in the red by the time i ran over to it. I'll try replacing the cap, any suggestions on where to get one or which ones will work? Yeah, I'm a total noob with regard to motorcycles....

The fan is loud. You would not have missed it. As for the rad cap: Hordpower or Honda dealer. Just picked one up, $37.00.

[Outdoorsman]

Just came back from Hell myself...118 in the shade by the Salton Sea (50 miles north of Mexico in California). Came back to a cool 98 here in Arcadia (just over 100 today). I saw a fan switch that sells new on Ebay. Supposed to help in hotter climates because it turns on sooner and stays on longer or something. About $55 or so. Goes right to the stock plug-in on the harness. If it got to spew'in on ya, I'd go with a new cap first too. In a lot of cases, your thermostat either works or it doesn't. Sounds like it is working if she does cool down.

[Schiff32]

she'll stay cool while riding, just gets got when sitting for a while( of which the guy I bought it from said to not do). I'll try the cap first then move to the thermostat. thanks for the replies!

[squirrelman]

first you need to determine that your cooling system is 100% full by removing radiator cap and filling to the top.
no cap will hold pressure if the bike is left idling in hot weather and the fan does not come on; as a matter of fact i'm guessing that is responsible for your problem.

test your setup by touching the wire that clips onto the radiator switch (left side) to ground (with key on) and your fan should start running.

the most likely and common failure is the thermostatic switch, not cap or thermostat.

[Schiff32]

Ok, filled the overflow to the upper line, it was empty... touched the wire that holds the radiator switch to ground (frame) and nothing happened. Not sure if i did it right, I just used a copper wire and jammed it to the switch and put it on the frame. Fan definitely is not coming on when the bike gets hot. Do i have to take the take off to get to the radiator cap?

[hawksonfire]

If the overflow is empty then the system is probably be very low on fluid as well. Remove the gas tank, don't forget to turn the petcock off and top your cooling system. Don't use antifreeze with silicates only ones designed for aluminum engines. You can eliminate the need to worry about which antifreeze is correct if you get it from a reputable motorcycle shop. Don't ride your Hawk with the cooling system partially dry or completely dry. Aluminum engines crater rather quickly without coolant.

[NT696]

Not sure if i did it right, I just used a copper wire and jammed it to the switch and put it on the frame. Fan definitely is not coming on when the bike gets hot. Do i have to take the take off to get to the radiator cap?

You have to take the wire off the thermo-switch, and touch the wire to an electrical ground. Your fan should work if the key is in the run or on position. The fan is electrically 'hot' all the time, and it just is waiting for the thermo-switch to complete the circuit.

Yes, the tank has to come off to get at the coolant system cap. It is located at the highest point to help keep air out of the system. Right next to the thermostat housing.

[Abquid]

overheating

My fan wasn't working when I got the bike, and failed the jumper test. Turns out the problem was in the ignition switch/wiring. I replaced the switch and the fan works fine.

One other note: It might be worth flushing the radiator (and cooling system) as well. After a lot of time enough stuff can accumulate in the radiator to create "dead" spots and keep it from working at top efficiency. Even when the bike isn't moving, I would think the radiator/fan should be able to handle temps below 100. We just had it up to 110 here and while I was never stopped longer than 5 min, the fan consistently kicked in and brought it to a reasonable level while in slow traffic, waiting for lights, etc.

[Schiff32]

first off, thanks for all the responses!! I know it can be frustrating trying to help a noob! the fan didn't kick on when touching the wire to ground, so I guess ill try a new switch and some fluid in the radiator. I've got a lot to learn about bikes... thanks again to everybody for the suggestions.

kevin