Hyosung MS3-250 overheating

[wayneb]

I've had this Hyosung MS3-250 for 4 years now, have 9600 miles on it now. Never had a problem with it overheating before, although others have said that their temperature guage never goes over 2 bars, mine would always run at 2 bars out of town, but go to three bars in town. The guage goes to 5 bars total. For the last week it still runs at 2 bars out of town, but after riding in town for a while it will go to 5 bars and overheat. I like to ride this thing, but am not the most mechanically inclined person. I took the front cover off and cleaned out the radiator fins, started the scooter and kept an eye on the fan, it would come on and off like it is supposed to, never went over three bars. Then I took it for a ride around town for about half an hour, never went over three bars. Then took it for a ride out in the country and it went to 2 bars. Came back into town and it went to 5 bars and overheated again after about 10 minutes of riding in town. I can't hear if the fan is running while the scooter is running, but I shut it off and turned the key back on and the fan was running. It's been like this for the last week. What do I need to do to find out what is causing this. I thought about buying a new sensor or thermoswitch, but I don't want to go buying a bunch of parts and not knowing what it is, the parts aren't real cheap for this scooter. Love to ride but don't like to fix them. No hyosung dealers in my area.

[Guest_3]

Welcome to ScootDawg.

If it were mine and its going on 9.600 miles, I'd replace the water pump & thermostat.

[spandi]

Have you checked (and replaced) your coolant?

[wayneb]

I replaced the coolant yesterday just to see if this would help, but it is still overheating in town. I've replaced the coolant every year since I have had it. I can't hear if the fan is running when the scooter is running, but if I remove the cover over the radiator cap I can look in with a flashlight and see it if is running. I just did this with the scooter running in the garage. The fan used to kick on when the guage hit three bars, and then shut off when the guage went back to 2 bars. But now it isn't kicking on until the guage hits 4 bars, and shuts off when the guage goes back to three bars. So it is running one bar hotter than it used to. Always runs at 2 bars when riding out of town though.
If it were the water pump, wouldn't it overheat all the time.

[wayneb]

I know how to do the basic maintenance on these things like changing fluids, but when it comes to mechanical I am not too smart. What is the difference between the sensor and the thermoswitch?

By the way, this isn't a chinese scooter. It is korean and it is built much better than chinese scooters, but the parts are a lot more expensive also.

[wayneb]

I've also noticed it takes longer to get a full charge on the battery, just noticed this about the same time the scooter started overheating in town. I always plug the scooter into a battery maintainer when I'm not riding it, and it usually just takes a couple of minutes for the light to go to a flashing green. Now the light stays on red for a long time before it goes to flashing green. I'm due for a new battery, but could this possibly in some way have anything to do with the problems I am having with the water temperature running hotter now?
Just found my receipt for the battery and it was purchased on May 22, 2010. So I think I will go buy a new battery anyway.

[blueboy5000]

Hook a voltmeter to the battery and verify you have proper voltage charging the battery (do this with the bike running). Sound to me like a bad VRR, which could cause a problem with the coolant sensor and fans (IE not turning fans on when it is supposed to).

If that is all good, change the waterpump and the thermostat and coolant.

[wayneb]

I replaced the battery and all is good with the battery now.

I did a lot of riding in town and out of town over the weekend, and it never went over 3 bars. Don't know why it was going to 4 bars and even 5 bars once for a couple of days. But once it gets to 3 bars now it stays at 3 bars. It used to go to 3 bars riding in town, but then when I went out of town it would go back to 2 bars, now it stays at 3 bars.

I don't know what to say about the price of the thermostat. The only place I can find it is on Alpha Sports and they want $168.96 for it. That can't be right, can it? Part number 17610HP8900HPA. This is a really nice performing scooter, but they don't make it anymore. I usually need to order the parts from South Korea, but they don't even have the thermostat listed. I'm really thinking about getting the new Honda Forza that is coming soon. With the Hyosung there is no dealer network around here, so if anything goes wrong it is up to me to fix it.

[wayneb]

Got a new thermoswitch from South Korea yesterday, replaced it this morning and rode around town for half an hour. Guage never went over 2 bars. Probably won't ride out of town until the weekend so will have to see how it does then.

[wayneb]

Did a mixture of town and country riding today, and it was running like normal again. But it's been a cool
weekend here, with a high of 68 degrees today. So hoping the thermoswitch was the problem, but have
to wait for hotter weather again to know for sure.

[4getful2]

Any place close to you that has a couple longer steep grades, where the motor has to work a bit? that would give you a better idea.
Take 3 or 4 bottles of water with you just in case.

[wayneb]

Just thought I would give an update. Replacing the thermoswitch did take care of the overheating issue. I was still having charging issues after replacing the battery, and it turned out to be a short in the stator. After replacing the stator and thermoswitch, the scooter runs like new again. Almost 11 thousand miles now, and these are the only repairs I have had to make so far besides the regular maintenance. Will probably have to look at replacing the belt and rollers over the winter season.

[spandi]

Great news! (ain't it wonderful when you get it working again?) Soon as you posted about the Thermoswitch I thought yep, that's probably going to be it. Fall is almost here, Ride! Ride!

[skuttadawg]

Were you going slow or dogging it ? Mine could get hot in the summer if I crept around campus with the 20 MPH speed limit but not run hot at cruising speeds with the increased air flow .

Did you burp the hoses to remove any air ?

Did you use automotive coolant ?

After reading , researching and talking to a guy at CycleGear I will flush out the Prestone and try Engine Ice since its formulated for motorcycles that run hotter than cars do since of the higher RPMs .

My fan only seldom comes on but in the last two weeks with it being warm it has came on and stayed on much longer . If its warm outside to you it is to the scoot as well .

Check the oil level and change if dirty .

Do a plug chop as if it is lean it will run hotter so you may need to upjet if yours has a carb

[wayneb]

As I said, changing the thermoswitch solved my overheating problems.