Why does.....

[WizzBang]

.....my trackbike run so hot ??


My bike is a CBR600RR-4, and during a trackday the temperature of the bike rises considerably, and then usually the last few sessions it runs very very hot.

1st couple of sessions = 85-90 'C
Middle sessions = 90-105 'C
Last couple of sessions = 100-125'C

Obviously this is not right and quite worrying , but over the last 10 days, other than running very hot, nothing else happens.  Regular oil changes don't reveal any degredation of the head gasket, but the water has to be going somewhere ..... right ?


Anyway, does anyone have any ideas ?

[Alzo]

It needs a bigger radiator to cope with the demand ?

[DaveH]

Is it losing water?

[WizzBang]

Water is being consumed throughout a day, and due to that fact I can rule out the need for a larger rad.


Been doing some searching on various CBR forums, and the only similar symptoms are pointing towards a cracked head.

[WizzBang]

Spent quite a while today having a good look over the bike in a bid to find anything obvious.

Made sure the system was topped up started it up and went through the procedure of squeezing hoses and tilting bike over etc.  refilled the rad and then the expansion bottle (HRC bottle mounted behind the clocks...see my project thread for details).  Continued to warm the bike up and noticed air coming out of the rad to expansion hose...only a little bubble, slowly, but when revving the bike, lots more continued to appear.

Stripped most of the hoses I could get to off as well, and removed the water pump.  Everything looks ok with it, but it doesn't spin easily, you can turn it with a finger, but not spin it....is that normal ?

Flushed the oil cooler just to make sure that there was a good flow there, and all was fine.

Took the fuel tank off and had a good look around the thermostat housing, and also the main waterway union into the block.  No obvious signs of leaking and all hoses look in good condition.


So, I'm none the wiser really

[Millhouse]

Well if its not losing water externally and it's not appearing in the oil you know the answer.

[WizzBang]

Ride it until it blows up ?

Strip the head off, replace gasket ?

Replacement engine ?

Have engine completely rebuilt and aim for higher power ?

[Green_Ninja]

Ride it until it blows up ?

Strip the head off, replace gasket ?

Replacement engine ?

Have engine completely rebuilt and aim for higher power ?

sell it a buy another one

[Millhouse]

More power you say??!

[Millhouse]

Head off and go from there. More than likely a gasket would sort the problem.

Riding it until it blows is a bit high risk...

[WizzBang]

Cant do that Iain, I'm not finished with this one yet

[Green_Ninja]

Cant do that Iain, I'm not finished with this one yet

seems it may be wanting to finish with you LOL

[ash]

Porous head

[WizzBang]

Seems that fate likes appearing at opportune times

2 CBR600RR heads have appeared on ebay, both have been flowed and ported and both have the kit cams in.


Hmmmmm......shall I ? 

[Millhouse]

Why have you not bought them yet?