Honda CBR 600RR Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
169 Posts
Discussion Starter #1
Hi folks. I have a 2005 CBR600RR with 30,000 miles on it. I've owned it for the last two years and it's used solely for track day riding. Other than suspension and a quick shifter the bike is completely standard.

On track the bike has always run quite hot at about 105C/221F degrees. However I was at Catalunya circuit in September and the ambient temperature was probably in the 30C/86F degree range and I saw the temp get as high as 114C/237F degrees. This is in a straight line at 152mph, so with maximum air flow through the radiator. This seems very high to me and also what I'm noticing is that my first couple of laps are about 2 to 3 seconds quicker than the later ones, so I suspect the bike is losing power at the higher engine running temperatures.

On the cool down lap I am completely off the throttle (very low revs) and rolling in top gear and the temp will drop to just under 100C/212F degrees, so I'm pretty confident that the coolant is flowing around the cooling system as it should. Back in the pits and the temp will start rising again. The fan kicks in when it should, but at speed I doubt it would be effective against the 152mph air flow coming through the radiator. I don't think a faulty thermostat or radiator cap is the issue as the temperature is rising and falling. I use normal anti freeze in the bike and all the air is out of the system. There is no requirement to replace the anti freeze with water for track days, only if you are racing.

So my question is aimed at those of you who either race or use their bikes a lot on track.

Do I need to invest in a bigger radiator or is there a problem with my bike?
 

·
Registered
Joined
·
169 Posts
Discussion Starter #3
Thanks Wazoo, I did read that sticky when I searched the forum for an answer and this part made me feel my concerns were valid: "operation of the bike to the 115 - 120C range is acceptable, how ever this is the range where you would want to find a safe place to park"

As for the high engine temp affecting my lap times, I think it may be, as I feel like I'm going at the same pace, but the lap times are 2 to 3 seconds slower. If the engine runs too hot then it's going to lose power. I can run pretty consistent lap times (within 0.5 to 1.0 seconds each lap), but a difference of nearly 3 seconds is a lot. The reason I think this is the issue is that I run the fast time on lap 2 or 3, when the engine is not yet up to 114C, then after that I'm 3 seconds slower and my lap times are consistent, but slower.

I agree, yes there are other variables, but I'm getting similar time fluctuations in 7 twenty minute sessions through the day, so that's why I think the motor is running too hot. Plus the sticky that you've highlighted will be figures for a road bike being ridden on the road. Not flat out on track. I've not had this with my previous 4 track bikes and they were all running standard engines and cooling systems, being ridden just as hard.
 

·
Registered
Joined
·
389 Posts
I have a 2003 cbr600rr (basically same bike) and have only been to the track once, but it was a really hot couple of days.

Ambient temps started around 90-95 F for the early sessions and up to 105 F (hotter on track) at the end of the day. In these conditions my bike would run mostly around 220, and at the end of the day and the end of the session, it would get up to 230-231.

As such I believe your temperatures are higher than they should be. No way you should be at 237 at the end of a fast straight in 86 degree weather. Something's not right.

Couple things you should do to help your bikes cooling efficiency.

1. Clean out the radiator. 30k miles worth of dirt, grime, and dead bugs is not helping air flow through the radiator and cool the water down.

2. Switch to a more water based ratio. I run about 75% distilled water and 25% Honda Pro coolant in my 600, year round (I live in San Diego). When I switched from 50/50 to the 75/25 the difference was immediately noticeable. Definitely gove it a try, or at least flush your coolant and do 70/30, 60/40, etc.
 

·
Registered
Joined
·
391 Posts
+1^^
Anyone know what the control module does with ignition timing when engine temperatures go up? Does it retard timing to combat a pre-ignition concern? If it does, could this result in loss of HP. I have no idea, just thinking out loud...
 

·
Registered
Joined
·
169 Posts
Discussion Starter #6
I have a 2003 cbr600rr (basically same bike) and have only been to the track once, but it was a really hot couple of days.

Ambient temps started around 90-95 F for the early sessions and up to 105 F (hotter on track) at the end of the day. In these conditions my bike would run mostly around 220, and at the end of the day and the end of the session, it would get up to 230-231.

As such I believe your temperatures are higher than they should be. No way you should be at 237 at the end of a fast straight in 86 degree weather. Something's not right.

Couple things you should do to help your bikes cooling efficiency.

1. Clean out the radiator. 30k miles worth of dirt, grime, and dead bugs is not helping air flow through the radiator and cool the water down.

2. Switch to a more water based ratio. I run about 75% distilled water and 25% Honda Pro coolant in my 600, year round (I live in San Diego). When I switched from 50/50 to the 75/25 the difference was immediately noticeable. Definitely gove it a try, or at least flush your coolant and do 70/30, 60/40, etc.
Thanks Honda-Power, yes I think they are higher than they should be too.

With regards to your suggestions, I actually got a second hand radiator as the one that came with the bike was well clogged up with ground. The guy I bought the bike from was the original owner from new and used it for commuting every day. He lived near farm land so I suspect that's where the ground came from. I also live on an island 5 miles by 9 miles with a maximum speed limit of 40mph, so I suspect it was never ridden enough to encounter any heating issues.

Intrigued by your suggestion of changing the ratio of coolant to water, I always thought antifreeze was the best coolant, rather than water? But I'll give that a go, thank you.
 

·
Registered
Joined
·
169 Posts
Discussion Starter #7 (Edited)
+1^^
Anyone know what the control module does with ignition timing when engine temperatures go up? Does it retard timing to combat a pre-ignition concern? If it does, could this result in loss of HP. I have no idea, just thinking out loud...
Interesting thought and sounds very plausible.

Just saw this when reading about the technical benefits of Water Wetter:

Since the octane of the available fuel is limited, increasing temperatures in the combustion chamber require retarding the spark timing which reduces the peak torque available. Higher inlet temperatures also reduce the density of the fuel/air mixture, reducing available torque further.

So you are spot on Wazoo
 

·
Registered
Joined
·
169 Posts
Discussion Starter #8
I have a friend with the same bike, but his has virtually every HRC part you could throw at it and I plan to speak to him today as I think he may have a solution. I'll get back to you when I hear what he has to say.
 

·
Registered
Joined
·
389 Posts
Intrigued by your suggestion of changing the ratio of coolant to water, I always thought antifreeze was the best coolant, rather than water? But I'll give that a go, thank you.
Nope, water is pretty much the best heat exchanger.

"The specific heat of water is 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance. As a result, water plays a very important role in temperature regulation."

You only need additives for freeze protection, boilover protection, and lubrication for the water pump/seals.

Is the second radiator a Honda radiator, or aftermarket?
 

·
Registered
Joined
·
391 Posts
Nope, water is pretty much the best heat exchanger.

"The specific heat of water is 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance. As a result, water plays a very important role in temperature regulation."

You only need additives for freeze protection, boilover protection, and lubrication for the water pump/seals.

Is the second radiator a Honda radiator, or aftermarket?
Additives also are needed for corrosion protection. Pure water would corrode things quickly.
 

·
Registered
Joined
·
169 Posts
Discussion Starter #11
Nope, water is pretty much the best heat exchanger.

"The specific heat of water is 1 calorie/gram °C = 4.186 joule/gram °C which is higher than any other common substance. As a result, water plays a very important role in temperature regulation."

You only need additives for freeze protection, boilover protection, and lubrication for the water pump/seals.

Is the second radiator a Honda radiator, or aftermarket?
Thanks for the tech explanation. Also you don't want just pure water in the cooling system as it furs up the aluminium and blocks waterways eventually. So beware when buying old race bikes.

The replacement radiator is I believe a Honda item.
 

·
Registered
Joined
·
389 Posts
Yes I forgot to mention corrosion protection, which is also the reason why it's so important to use distilled water!

I cringe to see people filling their bikes and cars with tap water.
 

·
Registered
Joined
·
5,094 Posts
is it possible that several different coolants have been used in the history of the bike?

Lost a ford pickup radiator due to the Cali state law to abandon ethylene glycol additives.

Later rescinded......
 

·
Registered
Joined
·
169 Posts
Discussion Starter #14
is it possible that several different coolants have been used in the history of the bike?

Lost a ford pickup radiator due to the Cali state law to abandon ethylene glycol additives.

Later rescinded......
Possibly, but I've drained and refilled with fresh coolant about a year ago. Will be changing to 75% Water Wetter and 25% coolant for next season.
 

·
Registered
Joined
·
169 Posts
Discussion Starter #15
I have a friend with the same bike, but his has virtually every HRC part you could throw at it and I plan to speak to him today as I think he may have a solution. I'll get back to you when I hear what he has to say.
Well I had a good chat with my mate and he has furnished me with a copy of the HRC Racing Kit manual and talked me through the changes he did to his bike. I'm probably going to do this to mine and see if it helps.

Remove coolant hose that runs from the water pump to the bottom of the thermostat housing and plug ends. You cut down the hoses to about 40mm long and then plug these. HRC supply plugs which are just aluminium solid round bar.

Do the same for the coolant hoses running to and from the fast idle wax unit.

Remove the innards of the fast idle wax unit, as once you've removed the hoses it would never drop the tick over revs!

Remove the thermostat completely. I'm guessing these mods allow the coolant to flow around the cooling system faster and it doesn't have to travel as far.

Downsides are probably the motor will take a bit longer to warm up, but not an issue as this is my track bike and always run it in the pits until up to temp. If it's cold I'll probably have to block the radiator with Gaffa tape to help it get up to temp.

Most of my track days are during the summer and generally pretty hot, so these changes shouldn't be an issue.

Also considering an oil radiator as well. We'll see.

I won't be able to know if all this works until next year, but I'll keep you posted as I go along.

Here's the HRC race manual. If you look at section E-5 you'll see the changes I'm talking about. http://www.risingsuncycles.com/images/PDF/parts-books/2005CBR600RR.pdf
 
1 - 15 of 15 Posts
Top