Hot Running Mama!

[commandodave]

Is it just my RC390 or "Do They All Do That?"

It seems my RC runs just at the verge of the fan kicking on. Easy ride on country roads on a 80 Degree F day. I was being a good boy and keeping the RPM below 7K. The temperature gauge was just below the break in the bars. Whenever I would come to a stop sign, the fan would turn on in a matter of a few seconds. Sometimes it would turn on while I was still moving if I was doing a slow coast waiting for a car or two in front of me to clear the intersection. It is annoying. Other water cooled motorcycles I owned run well below the fan start temperature. My Aprilia (with a digital readout and an analog gauge) would run 30 degrees F below the fan operating point. Even on hotter days. It would only come on if I was stuck in stop and go traffic on a hot day during a rush hour commute.

 

[Ryanthegreat1]

That is exactly how mine operates. Always 2 bars below the break for the "HOT" bars. Fan comes on with in town riding or after stopping for more than a moment.

 

[Bagwell]

Mine runs two bars under the upper break of the display, but mine doesnt always turn on at a light a few seconds after stopping. Depends on if I had a chance to run it at a little speed to cool it down a lil bit, but they do run warm and I think some of it is the lean condition at certian rpms that contribute.

 

[RoninJames]

yea mine runs the same. 2 bars below the break. i rode in downtown philly traffic one day and the fan was on the entire time. only time the temp went all the way to the break on the gauge.
i am going to flush the coolant after my first service and add engine ice and see if that helps at all. i will post a thread of my results then (prob about a week) if noone else does it before me

 

[Guyhowdy]

yea mine runs the same. 2 bars below the break. i rode in downtown philly traffic one day and the fan was on the entire time. only time the temp went all the way to the break on the gauge.
i am going to flush the coolant after my first service and add engine ice and see if that helps at all. i will post a thread of my results then (prob about a week) if noone else does it before me

I'm eager to see your results, I was also considering swapping out for engine ice to see if it would take longer for the fans to kick on. My bike is almost always 2 bars below the break and I've heard these bikes just run hot. My other bike is a Ducati 749 that will give you 3rd degree burns on your inner legs riding in slow traffic so the RC 390 isn't quite that bad, but the fans kicking on so much can be annoying. I even had them kick on last week the moment I slowed down to pull into a gas station...this was on PCH at night probably low 50s temperature, couldn't believe they even kick on when riding in such cool weather!

 

[micahpearlman]

From what I understand, the closed loop circuit, which controls the fuel mapping to approximately 5K RPM is extremely lean. The PowerCommander 5 (PCV) that KTM Performance will be selling should have control over the closed loop circuit and provide a proper map -- it would be assumed this would cool the operating temps bopping around town. Though not entirely certain that the fan coming on and the number of bars showing is a real issue other then it being annoying.

 

[micahpearlman]

Actually get your PCV while you can: http://www.rc390-forum.com/forum/ktm-performance/510-pcv-sale.html

 

[onethump]

Thought mine ran to hot, but seems it runs exactly the same as all of yours. Fans kick in lots usually when stopping at a light, but as some of you have mentioned even of colder days it kicks in alot.

 

[ArkansasDave]

So are the bikes ever overheating or you're just annoyed that a cooling system is working properly and keeping the bike in its designed operating range?

 

[reenmachine]

So are the bikes ever overheating or you're just annoyed that a cooling system is working properly and keeping the bike in its designed operating range?

I have overheated mine, but that was running it hard on uphill twisties for 26 miles. It puked a puddle when I stopped, a puddle of thick, neon green goo. Looked heavy on the antifreeze and here in SoCal I don't need that. I'll be flushing and refilling with distilled water and Motul MoCool next weekend.

By design, like any cooling system, the fan is thermostatically controlled and thus kicks on when the radiator can't do its job with the airflow available. The fan kicking on excessively just means that the radiator may be a bit on the small side for some climates. Changing the working fluid to something more efficient should do the trick.

 

[ArkansasDave]

So only one person has actually pushed fluid and had the gauge say they are overheating? When I pick mine up this week the coolant will be swapped immediately because it's going straight onto the track.

 

[commandodave]

Neither. I am annoyed that the normal operating temperature range is so close to the fan operating point. As an engineer, it offends my esthetic sense and points to an under designed cooling system. If it runs this hot on a mild day with break in RPM, what will happen when it is 40 degrees C., humid, and I am flogging it?

So are the bikes ever overheating or you're just annoyed that a cooling system is working properly and keeping the bike in its designed operating range?

 

[ArkansasDave]

That's a good question, maybe I'll ask some of the cup racers to see if they have had any overheating issues. My experience is most overheating happens in stop and go traffic, not flogging it on the twisties.

Also as an engineer you would know that the greater the difference between the temp of the engine and the environment then the more efficient an engine will be. You can't control the environment but they can the operating temp of the engine.

Has anyone one found out what their coolant temps actually are or just looking at some arbitrary bars?

Edit: The cup racer I talked to hasn't had any issues and he hasn't heard of anyone having issues with overheating.

 

[micahpearlman]

I've been racing in 100F+ conditions with no issues.


Sent from my iPhone using Tapatalk

 

[RoninJames]

as an aside, when i called to set up my first service the tech asked why i wanted to switch to engine ice, i told him that in city traffic the bike runs pretty hot and the fan is always on. he said thats good, the fan is doing its job lol. but he also said they can go in and adjust the temp the fan comes on.

now if the fan is doing its job at a certain temp i dont think i wanna mess w it too much so im gonna try the engine ice option first and see if that keeps it any cooler

 

[ArkansasDave]

Can you ask what temp the fan is set to come on from the factory?

 

[ray]

The DUKE/RC 200/390's are infamous to heat up all the time.

 

[desmo]

I was also curious.. a buddy of mine and I picked up our bikes and noticed the fan running a lot of the time. We figured it was due to break-in. But now it sounds like these little motors may be running lean. Anyone hear of a fuel/air ratio change from the factory?


Never mind:
http://www.rc390-forum.com/forum/ktm-performance/510-pcv-sale-3.html

 

[RoninJames]

i THINK he said it comes on at 190? and they could set it to 200... not sure if he was giving me exact numbers or just saying an example out of thin air (he may have said IF it comes on at 190 we can set it for 200)

 

[ArkansasDave]

190 is incredibly early for a fan to come on.