Hello, just joined the forum and looking for some help. I have a 05 CBR with 53k and flushed the coolant, ran the bike at idle brought it up to temp 98, increase the rpm’s and fan came on at 102, buttoned it back up went for ride. Roughly 2km stop at lights and the bike started to over heating reached 120 and I shut it off and walked it home.
With the fairings off I see the over flow bottle was full, so that would tell me the coolant reached boiling point? So I am thinking maybe the thermostat it defective, I remove it and test it in boiling water and it opens at 101-102 degrees, reinstall. Now I am thinking I had an air lock so empty the over flow bottle top up the rad start and let idle, reach operating temp. It burp and spit tunes of air out (what a mess) top it off put the rad cap back on cleaned it up ( I also checked the coolant pump)
road it hard for around 600km no issues until Saturday went out road it hard and the ran into some traffic, out door temp 21, 5 min in traffic and the bike is around 110 fan rings down to 107 drive off temps goes well into operating for the moving bike. when I get home I notice the over flow bottle is ful again. This has never happens before when i have changed the coolant.

The bottle is full now should I just empty it because maybe too much coolant in the rad? But on the other the hand it is not full either. I don’t know what to do!

 

Radiator cap is what lets coolant out into reservoir.

Also what kind of coolant are you using? Propylene glycol has lowest heat-transfer rate and would run hottest. Ethylene glycol has faster transfer-rate and would run cooler. Distilled water + Redline Water Weter has fastest transfer-rate, about twice as fast as propylene and will run coolest.

 

Hi, and thank you for your reply. I am using Prestone all vehicles. I am not sure if it is Propylene glycol or Ethylene glycol?

 

Most likely it's normal ethylene glycol.

Pressure-test radiator cap. It may be worn out. Also inspect its seating surface on radiator neck for good sealing.

 

Since it is 10 years old I am going to replace it, OEM is only $30 bucks. Let you know how it works out.

thank you

 

LONG POST COMING UP

Hi everybody,
Kodi nox
I purchased a utilized 05 cbr 1000rr as of late and it has a truly unusual overheating issue.
In around 30mins max the temperature will climb to 100°-106°C on the open streets without traffic..In lower speeds it won't cool and the temperature increments considerably quicker. Fan gets on at 104°C yet doesn't have an effect.
The odd thing is I need to keep up with around 70-90mph.. On the off chance that I ride quicker like around 120-150mph the temperature shoots up to 110-113°C in the blink of an eye. .
Also, the equivalent occurs assuming I ride more slow than 70mph or inactive at the lights for more than 8-10 seconds. in a matter of seconds the temperature will shoot up to 115°C+

 

That does sound really strange...
Couple of questions, have you checked the thermostat to see if it is actually operating correctly? Secondly does the fan actually turn, I know it sounds silly but on my old F3 the fan blade became detached from the motor which I hadn't noticed (doh) also it has been known to have the fan motor connected the wrong way round in effect pulling the hot air from the engine over the rad rather than drawing fresh air in?

 

Hi, so I have tested the thermostat in boiling water and at 98 degrees it open. Further to my research I also have found the rad cap might be my issue, because I have tested the whole cooling system and everything is operating properly. With the off chance the thermostat is part of the problem I am replacing it as it roughly 10 years old the same the rad cap so I am replacing once I get the parts and I will put HP coolant Honda OEM. Let you know when I have changed it all.

 

Fingers crossed it is the cap then leaking pressure, it could also be a faulty sensor. Do you have access to a non contact digital thermometer to let you know really how hot it is getting as it is very unlikely the temp could rise that quickly? If not you should be able to pick one up for around $15.

 

Ethylene glycol has faster transfer-rate and would run cooler. Distilled water + Redline Water Weter has fastest transfer-rate, about twice as fast as propylene and will run coolest.