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Discussion Starter · #1 ·
Hey guys,
A little history: I recently purchased a used '10 690 SMC with around 1000 mi. The PO put on Akrapovic exhaust and dealer installed remap. The bike was primarily used on the track. I went out a couple of weeks ago when it was 80 degrees F. Bike overheated on the expressway. I discovered it was low on coolant. I flushed the coolant and replaced with Engine Ice coolant. I also changed the oil with Motorex 4T 10w60. I took the bike out last night 75 degrees F temp. and it overheated in stop and go traffic. I stopped and let it cool off. No coolant leak or smoke. I decided to go home, about 25 miles on expressway. Bike was fine with 5 bars on the temp gauge . Near my exit, I took it for a quick speed run up to around 100 mph and right back down to 65-70 mph. Bike overheated again and I had to limp home the last couple of miles. Again, no coolant leak, no smoke. The hoses to and from the radiator were hot. I searched the archives. Should I replace the coolant with Motorex, bad thermostat, leaky head gasket, faulty temp sensor? Any ideas are greatly appreciated.
 

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first guess would be bad thermostat. did the fan even come on at all?

just curious though, how do you know it's overheating if it wasn't blowing steam or burping coolant? when the bike runs too hot the pressure increases causing the radiator cap to open up and excess pressure and coolant into the recovery tank.
 

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Discussion Starter · #3 ·
Thanks for the quick response. What would happen is the bike would lose power(limp mode), the temp. gauge would go to the top with all bars lit and then the red temp. light would come on. My first thought was the thermostat also.
 

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cheap things would be to try first the thermostat and maybe the temp sensor.

After that it would be back to the dealer for me...
 

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Discussion Starter · #6 ·
The fan did come on. It would stay on after I shut the engine off. It would then turn off automatically when the temp gauge would come down a few bars.
 

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if its overheating only in stop ang go traffic then its normal and nothing to worry about. i do a lot stop and go in town and when its hot outside the temp gauge goes up to the 2nd bar from the top(with the fan kicking in), but once i start moving for a minute or two it gets back to normal.
 

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You could have air in the system or possibly a bad rad. cap...did you check the owners man. before you changed the coolant?
 

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I have a 2008 690 SMC with 10K miles. Haven't changed the radiator fluid. Though, I have kept an eye on the level of it. I have enough where I could probably replace it, but don't think I will until I notice the bike runs hot. I've only had the fan come on a few times, and only once did the bike reach full bars (during stop and go traffic for like an hour). So, not sure what it could be unless the fluid was filled with part water or something.
 

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Discussion Starter · #13 ·
Thanks for all the responses. I ordered a new thermostat and when I pull the old one I will test it in some boiling water to see if it opens.

Garconis - I filled it with undiluted Engine Ice.
alarka - I haven't checked the rad. cap and I followed the owners manual when I refilled it.
dodojanik - the bars wouldn't go down after I started moving.
 

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Try to check the state of the radiator, and the insides of the cooling system, and check for scaling etc, if it was used as a trackbike with water and no antifreeze, and left in there for 1+ years there could be some problems.

I have seen it happen before
 

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Crossroads; describe what the bike did when it "overheated" and you limped it home. Also, after what you've done, is it still acting up?
 

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if its overheating only in stop ang go traffic then its normal and nothing to worry about. i do a lot stop and go in town and when its hot outside the temp gauge goes up to the 2nd bar from the top(with the fan kicking in), but once i start moving for a minute or two it gets back to normal.
No! Overheating is not normal, regardless of traffic conditions.
 

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So try to leave ur bike running on idle for 15minutes and check the temp gauge. It will be way over the fifth bar and the cooling fan will switch on as well.
 

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So try to leave ur bike running on idle for 15minutes and check the temp gauge. It will be way over the fifth bar and the cooling fan will switch on as well.
overheating means the temp is getting up so high the bike is burping coolant and blowing steam.

it's normal for a bike to run hotter when it's been idling for 15 minutes, but that doesn't mean it's actually overheating. the fan will kick in to keep your bike from reaching that critical point, not when you've already gone past it.
 

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overheating means the temp is getting up so high the bike is burping coolant and blowing steam.

it's normal for a bike to run hotter when it's been idling for 15 minutes, but that doesn't mean it's actually overheating. the fan will kick in to keep your bike from reaching that critical point, not when you've already gone past it.
indeed.


Traffic in 75- 90degree weather, you will experience up to one bar before the temp stack is "full"

This is fine. if you ever "fill the stack" w/ temp indicating bars, then you are actually "overheating" -- as mentioned, this will also be evident by a significant amount of coolant flowing from the overflow lines and such.


5bars is the MINIMUM OPERATION temperature. gl have fun!
 

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Discussion Starter · #20 ·
Thor450: What would happen is the bars on the temp guage would go all the way to the top. The sound of the exhaust would change deeper and louder and I would lose power. It wouldn't rev past 4000-5000 rpms and I could only go about 35 mph. Also, the red temp warning light would come on. When I stopped, I could hear the fan was on.

Update: I replaced the thermostat and replaced the Engine Ice coolant with Motorex yesterday. The inside of the radiator looked okay with no noticeable scaling. I took the bike for a short spin between rain showers and the temp here was 68-70 degrees F. I let it idle for 10 minutes and the bars on the temp guage made it to 2 from top and did not go higher. When I rode it, the bars immediately came down to around 5-6. I will have to go for a longer ride but I think its better. Incidentally, I put the old thermostat in boiling water and it opened perfectly. So, maybe its the Engine Ice coolant. The bikes still under warranty so if its still the same, I'm off to the dealer.
 
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