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View Full Version : RC51 Owners Please Chime In



RC51Sp2
Oct 10th, 2014, 07:42 PM
I wanted to know what kind of temperatures you guys are running in the valley.

In 100 degree weather I was getting over 230 degrees when riding below 45-50 MPH. Is this abnormal?

Over 70 MPH it would cool down as low as 179 degrees.

Sticka
Oct 10th, 2014, 09:05 PM
I am not an RC owner but I have a TL1000R.
230 sounds pretty hot.
My TL fans come on at 225 (only in traffic, never when moving). Average running temp is 182.

RC51Sp2
Oct 11th, 2014, 12:31 AM
I am not an RC owner but I have a TL1000R.
230 sounds pretty hot.
My TL fans come on at 225 (only in traffic, never when moving). Average running temp is 182.

Thanks for the feedback. Do you have dual fans? Which direction does the air flow when your fans are on? Mine pull air in at about 220 and go off at about 210. They have very little flow. Pulling air is opposite of the airflow at speed. It seems like an odd design. I can't tell if the ECU logic is the same while moving. I will have to hook some sort of LED test light to see if the are running when I am riding under 50 mph.

Sticka
Oct 12th, 2014, 10:37 AM
Yes, 2 fans on the TL1000R's.
They are at the back of the radiator and the pull the air through from front to rear.

Jetstream01
Oct 13th, 2014, 03:03 PM
Eric those are perfectly normal temperatures for an RC51, don't worry! My bike gets about the same in hot weather. The RC51 is just a hot running bike since it has kind of a dumb cooling system (other v-twin sportbikes don't usually have side radiators).

In my experience, my bike peaks at about 230 degrees and won't get much hotter since the fans can keep it around there.

RC51Sp2
Oct 16th, 2014, 07:27 PM
Yes, 2 fans on the TL1000R's.
They are at the back of the radiator and the pull the air through from front to rear.

Hi, do you have aftermarket pipes on your TL? I would like to check out your bike sometime. How do you like the handling of the TL? I had read in magazines many years ago that there we handling issues.

RC51Sp2
Oct 16th, 2014, 07:30 PM
Eric those are perfectly normal temperatures for an RC51, don't worry! My bike gets about the same in hot weather. The RC51 is just a hot running bike since it has kind of a dumb cooling system (other v-twin sportbikes don't usually have side radiators).

In my experience, my bike peaks at about 230 degrees and won't get much hotter since the fans can keep it around there.

Thanks Patrick, you are a great resource. I just read your interesting thread about buying a RC a couple of years ago.

MadKaw
Nov 15th, 2014, 10:53 AM
I have owned two RC51s but they were both 2001 models and the fan control system is different.


for emission compliance reasons the cooling fans are set to come on around 220 or so. The RC51 cooling system was never designed for traffic or low speeds. It is designed to have good airflow at high speeds and the fans are for low speed. However for emissions the trigger temp is just too high.

The secret on the RC that I found is to have the fans come on sooner so that the temp never climbs that high in the first place. On the early RCs the fan temp control is controlled by a simple temp switch in the radiator. It took me some time but I came up with a fix for the early models by figuring out the metric thread size and pitch of that temp control switch. Then I spent quite some time going through a book at a car parts store looking at temp control switches and I found a match thread size and pitch with a trigger temp of 180 degrees. That took care of my bike.

If yours is a later model RC then you dont have such a luxury. you do have a fan control relay located back behind the seat but the control for that relay is your engine ECU. When your ecu reads the temp from the radiator temp sensor (not a switch) it closes the relay and turns on the fans.

You have two options for triggering your fan control relay at a lower temp. Your first option is just install a manual toggle switch up on your bars somewhere and provide a manually controlled ground for the fan relay. Turn it on whenever you want. The lower the better.

Second option- there are aftermarket hotrod electric fan kits that you install on a hotrod. These are sometimes controlled by a temperature sensitive switch that you install right onto the backside of your radiator with a zip tie and then wire it into the fan control relay.

RC51Sp2
Nov 15th, 2014, 01:26 PM
Thanks MadKaw, very informative. Nice looking RC. I'm having a lot of fun on mine. I think I going to use the defense "Officer, I was speeding to keep my bike cool" :D

GusGus748s
Feb 17th, 2015, 11:41 PM
I would suggest for you to go to speedzilla forum, and search Spal Pusher 5.5" and 5.6" fans. These are bigger fans that you need to attach to your radiators, and they will blow more air, and cool down your RC51 faster. Here are a couple of pics I found on speedzilla.

RC51Sp2
Feb 18th, 2015, 02:07 AM
I would suggest for you to go to speedzilla forum, and search Spal Pusher 5.5" and 5.6" fans. These are bigger fans that you need to attach to your radiators, and they will blow more air, and cool down your RC51 faster. Here are a couple of pics I found on speedzilla.

Thanks, I will check that out. Do you have any heating issues with your Duc? If we ride with you are we all immune from tickets under the profession courtesy umbrella of your fellow brethren? :)

GusGus748s
Feb 18th, 2015, 06:41 AM
Thanks, I will check that out. Do you have any heating issues with your Duc? If we ride with you are we all immune from tickets under the profession courtesy umbrella of your fellow brethren? :)

Never had any of my Ducs run as hot as the RC. This is primarily due to the side radiators of the RC. I havent been on a motorcycle for almost 5 years now. I sold all of them.

There's no immunity anymore lol. Probably one of the perks I miss when I was in that profession.

Jetstream01
Feb 18th, 2015, 01:42 PM
The RC51 could definitely use some better cooling. I don't understand this design decision...the idea of a V-twin is to make the bike narrow, right? So why put the radiators on the side of the bike?? Come on, Honda...they do the same thing on the Interceptor and it also runs hot. The way Ducati does the radiators makes a lot more sense, and they're a lot more narrow because of it.

GusGus748s
Feb 18th, 2015, 02:38 PM
The RC51 could definitely use some better cooling. I don't understand this design decision...the idea of a V-twin is to make the bike narrow, right? So why put the radiators on the side of the bike?? Come on, Honda...they do the same thing on the Interceptor and it also runs hot. The way Ducati does the radiators makes a lot more sense, and they're a lot more narrow because of it.

Nicky Hayden's RC51 had a front radiator.

Jetstream01
Feb 18th, 2015, 03:53 PM
Nicky Hayden's RC51 had a front radiator.

Yeah, which makes it weird that they designed the street bike with side ones. I will say it's not that the bike runs TOO hot (i.e. has mechanical issues because of the heat), it just runs hot. Never seem to lose any performance or anything from it.

RC51Sp2
Feb 19th, 2015, 01:21 AM
Never had any of my Ducs run as hot as the RC. This is primarily due to the side radiators of the RC. I havent been on a motorcycle for almost 5 years now. I sold all of them.

There's no immunity anymore lol. Probably one of the perks I miss when I was in that profession.

I understand your career change and selling of your rides. Maybe you'll throw a leg over after he's on his own.

RC51Sp2
Feb 19th, 2015, 01:26 AM
Yeah, which makes it weird that they designed the street bike with side ones. I will say it's not that the bike runs TOO hot (i.e. has mechanical issues because of the heat), it just runs hot. Never seem to lose any performance or anything from it.

Go figure. Anyways, as you know if we keep the speed up there is no heat issues. I'm sure Honda was not designing the RC for stop and go traffic (even the street version).

Jetstream01
Feb 19th, 2015, 07:37 AM
Go figure. Anyways, as you know if we keep the speed up there is no heat issues. I'm sure Honda was not designing the RC for stop and go traffic (even the street version).
That's definitely true.