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Trackbike engine temperature

2K views 16 replies 4 participants last post by  Lbknuckles:-) 
#1 ·
Hello,

I need some advice, my Kawasaki ZX6R 2004 is used solely on track and I can not figure out if there is a problem with the cooling system.

Ambient temperature is about 38-40C/100-104F and the bike runs at 95-105C/203-221F while the Hondas (600RR) I ride with are about 10C/50F lower.

Is this normal operating temperature? I run 10W50 oil, may this be a reason?

Thank you
 
#2 ·
I've just spent some time on my rad and fan switch sorting cooling.

Manual says fan should kick in around 92/104 degrees c. This would normally be when there is insufficient airflow through the radiator.

Check your rad, does it have blocked/damaged fins?

Drain the system, use a clean bucket to store the coolant. Remove the rad and leave it in a tall bucket of water overnight.
Using a soft brush and a non acid wheel cleaner brush the fins carefully up and down. (not side to side as likely to bend them)
I used a small flat blade screwdriver to straighten up damaged fins and hosed it down after with a low pressure spray.
Reverse flush the radiator to clear any blocked channels.
Refit/refill and run up checking the fan cuts in as normal.

Have you had the plugs out to check the condition of them?
Colour and condition may indicate overheating in the cylinders. Maybe why the cooling system is struggling as well. That would possibly be a lean fuel mixture. Have you made any fuel changes recently?
 
#3 ·
Do you use fully synthetic oil?

One of the proven benefits of fully synthetic oils is that they lower average operating temperature and they are definitely suited to track use.

You could also install a cooling fan switch in order to use it whenever you like (when there is not much air flow between track runs) too:

 
#4 ·
Thanks for you comments. So, are you saing that the engine is running hot? What should be the temperature?

1. Fan switch, sensor are all working as supposed
2. Rad seems pretty well, has a protector on top
3. Spark plugs are changed regularly
4. Oil is fully synthetic.

Thanks for the switch link, I will check it out.
 
#5 ·
You are welcome, I don't know what is the perfect temp, as long as the overheating - temp light is off I don't think that the engine is running dangerously hot, maybe it is designed to work a bit hotter than the equivalent Honda engines.

So as long as there is no real threat you can experiment with the manual fan switch and maybe a high end coolant fluid, like Engine Ice or Wetter Water, but first check with the track regulations as some tracks only allow water as coolant because it is less slippery.
 
#6 ·
Another thing to consider is the radiator cap.
Radiator relief pressure is set between 14~18psi
If it's too low then the water will boil causing air bubbles and the result would be over heating.
Know anyone with a spare you could put on?

Bottom line, it's not overheating as it would flash 'HI' on the dash from memory. As long as the temp is constant then it would suggest the system is doing what it should.
Mine runs in the 90's when worked but only hits 100+ when stationary in traffic.
 
#7 ·
Another thing to consider is the radiator cap.
Radiator relief pressure is set between 14~18psi
If it's too low then the water will boil causing air bubbles and the result would be over heating.
Know anyone with a spare you could put on?

Bottom line, it's not overheating as it would flash 'HI' on the dash from memory. As long as the temp is constant then it would suggest the system is doing what it should.
Mine runs in the 90's when worked but only hits 100+ when stationary in traffic.
Thanks,

the cap is fairly new, changed it when I saw it overheating and because of crash the radiator neck was bent and I had to fix it.

I will run it like this, and clean the radiator and possibly install a fan switch.

I guess as long as it is not flashing HI it is OK. 1,2,3 gear on the track and 40+ degrees outside is quite hot.
 
#15 ·
Well one of the differences is the zx6's of that time redline higher than the Hondas. My '07 redlines at 17k (bore over stroke) where I think the Hondas of the time were at I think 15k (more of an equal bore to stroke ratio). This could contribute to heat difference between the two machines. No matter. I raced for years without running the fan in the deserts of AZ and NM for years to no ill effect. Just had to be careful not to sit idle too long. Engine Ice or some other non glycol based coolant would help a little if you're that concerned about it. Which you should be running anyway on the track (if not just plain distilled water).
 
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