Hot Hot Heat - Or How to Cool Your RC390.

[cornerslider]

After following all the issues on the forum, I did 3 things to mine. One was going to ICE coolant. Drained and flushed the system and then flushed the system once with ICE to be sure I had full strength. Second I added the higher pressure radiator cap. Thisrd, I pulled the fan and trimmed the shrouding away. Result is one to 2 bars cooler running and the fan doesn't cycle as much now. I live in Houston, hot and humid and did a bike school track day the 30th of July and the bike ran cooler all day.

+1..... To what he said!!!! I baby my bike on the street, and I run the hell out of it on the track. I did ALL of the above, and got the same results. My best advise to ANYONE buying an RC390- Learn to work on your bike yourself, and don't depend on the factory warranty for anything other than a catastrophic failure.... Just my opinion-



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[=maz=]

SPAL fan, 1.6bar rad-cap, only run distilled water in my race bike(that's the rules), head gasket and base gasket through cjwells, machined head and barrel at time of install...bike still blew the head-gasket. It actually blew between the 2 gaskets that make the head-gasket.

My best advice to anyone buying an RC...be aware of the warranty stipulations and don't take "No" as an answer from your dealer...demand evaluation from KTM(in what ever country you're in) on all warranty claims.

 

[=maz=]

it is a lot easier for me to critically think about the other side of the argument when the rebuttals aren't just a bunch of snarky comments.

Don't feed the troll buddy.

 

[stevieboy]

+1..... To what he said!!!! I baby my bike on the street, and I run the hell out of it on the track. I did ALL of the above, and got the same results. My best advise to ANYONE buying an RC390- Learn to work on your bike yourself, and don't depend on the factory warranty for anything other than a catastrophic failure.... Just my opinion-



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I agree with the part about the dealers. Mine was clueless at best and misinformed at worst for service. Fortunately I have a local Yamaha dealer that I have been working with for almost forty years. He will work on anything I bring in although he was a little pissy with the Aprilia two-strokes!

 

[WA390]

Ok guys/gals, from what you have seen is the fan failure still an issue with the 2016 model and does this seem to be an issue only for peeps that track the bike? New 390 owner in about a week. Will be doing moderate commuting, joy riding but no track days. Should I be concerned or just wait for signs of a failure? Obviously one would want to do the fan and coolant mods to be safe, but trying to gage the risk.

 

[btalont]

new 2016

Ok guys/gals, from what you have seen is the fan failure still an issue with the 2016 model and does this seem to be an issue only for peeps that track the bike? New 390 owner in about a week. Will be doing moderate commuting, joy riding but no track days. Should I be concerned or just wait for signs of a failure? Obviously one would want to do the fan and coolant mods to be safe, but trying to gage the risk.

Given the evidence, I think changing the coolant and radiator cap are mandatory. My 2015 fan hasn't failed so I just trimmed the shroud. I believe it is necessary given he flow you gain but that's you call on a new bike. I have tracked mine enough now to know the radiator has enough capacity if it has adequate air flow.

 

[Deleted member 452]

Here's my experience after changing the head gasket & water pump 5K miles ago. My bike always ran 2 bars away from the hot mark before, during, and after the head gasket/water pump replacement. I installed a SPAL fan, high pressure radiator cap, and Engine Ice as preventative maintenance 2K miles ago and now it sometimes runs 1 bar cooler or 1 bar higher (doesn't matter how hot it is outside). The overflow reservoir also pukes coolant and goes from the low mark to the high mark often. I don't think the SPAL fan cools the bike more efficiently than the OEM fan but I don't have CFM #sto prove it and I'm thinking about trying out Evans coolant because it doesn't expand and contract like water/glycol products...

 

[Diploman]

An OEM fan with the shroud cut away might be closer in output to the SPAL fan, but I still believe the SPAL moves more air. But there are other reasons that justify moving to the SPAL:
-- It is unfailingly reliable. No issues with self-disassembly or intermittent /sporadic operation;
-- It is far quieter than the OEM fan, almost imperceptible at a stop, in contrast to the loud, annoying, insect-like whine of the OEM fan. This alone is worth the price.

 

[Bagwell]

Here's my experience after changing the head gasket & water pump 5K miles ago. My bike always ran 2 bars away from the hot mark before, during, and after the head gasket/water pump replacement. I installed a SPAL fan, high pressure radiator cap, and Engine Ice as preventative maintenance 2K miles ago and now it sometimes runs 1 bar cooler or 1 bar higher (doesn't matter how hot it is outside). The overflow reservoir also pukes coolant and goes from the low mark to the high mark often. I don't think the SPAL fan cools the bike more efficiently than the OEM fan but I don't have CFM #sto prove it and I'm thinking about trying out Evans coolant because it doesn't expand and contract like water/glycol products...

Are you running any kind of fuel controller on the bike other than stock ECU?

 

[WA390]

Thanks for the details everyone! Will add the Spal, the better fluid and cap to my mod list.

Would the duke swap be essentially the same steps with the addition of some faring removal needed: Spal Fan Instal How To - KTM Duke 390 Forum

Thanks again!

 

[Diploman]

The Duke and the RC are essentially the same bike - engines are identical. Once you remove the fairings just follow the Duke How-To.

 

[WA390]

The Duke and the RC are essentially the same bike - engines are identical. Once you remove the fairings just follow the Duke How-To.

I thought so, but wanted to be sure! Thanks

 

[Deleted member 452]

Are you running any kind of fuel controller on the bike other than stock ECU?

Yes and my AFR is 12.8 so it's definitely not lean.

 

[benmh]

hi there, i recently suffered from overheating issues on my rc390. I live in the UK and rode in low temperatures 0 - 10 degrees and yet more than a few traffic light stops (stopped in neutral) id hear the fan and then trying to pull away the bike would cut out and sometimes it would start again but othertimes id have to wheel it to the side of the road and let it cool. Anyway, i decided to take it in, the mechanics said nothing was wrong with the coolant, fan, engine etc during the service. So i took it away but it kept happening so I took it back and changed the engine coolant with engine ice as recommended but the guys there also said they adjusted the adapitted valves. It's solved the problem, the engine still gets hot (believe me i can feel it on my legs) but the bike does not cut out when stopped at lights or junctions. Im not very mechanically minded so im not even sure if adapitted valves are a thing but thats what it says on the reciept. does anybody here know anything about this?

 

[Diploman]

I have not the slightest idea what "adapitted" valves might be (nor does Google). This does not appear to be accepted English-language automotive/mechanical terminology. One might wonder what those mechanics were smoking when they said they had adjusted the bike's "adapitted valves". I suspect they meant to say they checked and adjusted the bike's intake and exhaust valves, a customary operation on 390 engines. It does seem likely that out-of-spec valves could cause the motor to run overly hot. In any event, it is a good outcome that whatever they did with those "adapitted valves" has resolved your cooling problem.

 

[andysodandy]

Can anyone tell me what is NORMAL temperature readings as in how many bars off full hot should our bikes sit on?

Mine sits 2 bars below HOT and doesn't go any less. When stopped for traffic the fan comes on and it keeps it at the 2 bars which is a good thing I'm hoping as this heat stuff is beginning to worry me.

Is 2 bars off full hot good or bad for the RC390?

 

[Diploman]

Andy, My 390 has never experienced cooling problems. Prophylactically, I have fitted a SPAL fan, Engine Ice and a 1.6 bar radiator cap. During operation, the temperature bar sits consistently at 2 bars below hot, and moves very little. Others (unless their bike happens to have a cooling issue) typically report the same temp indication. I think 2 bars below hot is the 390's normal working temperature. So I think your bike is right on spec.

 

[Bonarj]

Hi there. Newbie here. Can anyone post a link where you guys bought the exact SPAL fan that you guys use and the 1.6 radiator cap (assuming you bought it online)? Planning to buy those and fit it on my RC 390. Thank you and Ride Smart.

 

[Deleted member 452]

Radiator cap:
Chassis - MNNTHBX

SPAL fan:
https://www.amazon.com/Spal-3010301...&qid=1489160457&sr=8-1&keywords=SPAL+30103011

 

[stevieboy]

Or look on ebay. I got mine for $40.00 including shipping.