Overheating ????

[afritts4u]

I went to glamis last weekend and my bike kept overheating. Their are no leaks in the radiator, externally the head and base gasket look good. The impeller is spinning like it should. The only part of the cooling system that looks bad is the radiator. About 50% of the little baffles are bent over. Could this alone be causing my bike to overheat after about 5min of riding?

I realized I rode it hard for about 20min with almost no water in the radiator before I noticed it. Is it likely I jacked up my top end? It still runs OK, and starts first kick, but was definitely down on power?

Imp racing in the Ellsinore Grand Prix this weekend and need to figure it out fast. I will straighten out all the little fins and hopefully that is it, and hopefully there is no perminate damage!

[hughes]

Compression check you top end. When you fill the cooling system with coolant you need to bleed the air out. My 87 500 has a bleed screw on top of the head. Air will casue the system to vapor lock. Just because coolant level shows full at the rad. cap doesn't mean the whole system is full you still could have air trapped in the cylinder or head. I waste a lot of coolant just to make sure that the air is out.

[Johnniespeed]

Hughes is right about the air getting blocked in the cylinder. I too waste a lot of coolant making sure no air is trapped.  I hope your impeller 'always' spins.  You have a good idea about strightening the fins.  I hope you have time to do a little trail testing before your race. GOOD LUCK racing!!!!!
  The loss of power has me concerned, I would invest in some seat time. While we are on the overheat subject, has anyone actally measured the coolant temp on a known good bike to see what the operating temperature of the coolant shold be?

[KXcam22]

Also check your impeller. Sometimes they come loose and then all cooling comes to a stop (although everything appears to be top notch). You may be able to pop off the rad cap and verfiy this. I can't remember if you can see the flowor not. Cam.

[hughes]

Yes, You can see the coolant flow. I have checked mine.

[Kawadougie]

I have found that my bike will overheat when I use the thinner head gasket that comes with the Cometic gasket kit.  The stock head gasket is about twice as thick as that one.  I've just ordered the optional 1.6 pressure cap pt:49085-1073. Stock is 49085-1070 rated at 1.1.

[afritts4u]

I purged the system and even with beat to hell radiators the thing is running cool. Turns out I just did not have enough water in the system

[Johnniespeed]

That is good news !   Have fun riding, I am going to snowblow my driveway. ( note scarcastic tone due to location envy )

[afritts4u]

KX500 could may make a good snow blower? Of course I dont know about blowing snow, just warm sand and dirt blowing behing my rear wheel all year long. LOL Then again I have to sit in traffic for 2 hourse to get home to my $ 1 million cardboard box in the creek, so I may never make it home to ride.

[KXcam22]

Yeah. Lots of +/- tradeoffs wherever you live. Take it from me, the KX roosts snow quite nicely. Cam.