I begining to wonder if I've warped my head or cylinder.

Symptoms:

In most situations the bike runs cool. The fan works fine. But in a long steady climb the motor reaches a point and then spits copious amounts of fluid out. After a bit the fluid turns to steam which increases with throttle.

In addition the GM auto trak gains a lighter shade of blue after a long ride.

For example, today this happened several times on larger climbs (about 1000-1500 vertical feet). I am in the habit of refilling the radiator when this occurs. It took 6 oz to top it off.

I was told that this could be the inner o-ring on the head, but I have replaced both and symptoms seem the same.

The engine runs fine through all this.

thoughts?

ty sirs

Does your trans fluid look like it has water in it??? Water pump seat could be leaking

Hi there.

A couple of thoughts, have you checked that the overflow pipe from the radiator fill cap is not blocked or damaged.

Where is the fluid being discharged from?

Maybe try and link the 2 wires from the thermostat together and have the fan run continous for a while to see if the fan can cope with the hotter climatic temps in Idaho?

Are you using any type of antifreeze coolant in the water, this will also aid cooling efficiency.

Are you losing any water anywhere obvious other than when it overheats?

If your losing water through the water pump seal then your transmission oil will be emulsified.

Cheers.

waterpump seal sounds good,

But id like to add that adding antifreeze to your water wont aid cooling, apparently it does the reverse.

If you add 'wetter water' to your mix then yes its better but otherwise no. I got this from the bottle of the wetter water that my mate used in his tuned car. The more antifreeze you added the worse the cooling was.

Take that as you will, just thought id add my two cents

I have same bike, same issue. I jetted mine down to a 112 main, dropped needle one, live at 7,000' in mtns.

Mine will only overheat when sustained WOT, at 3/4 throttle, it will run all day not puking coolant.

I figure the main jet is too small for sustained WOT use, and it leans out. My plug will read really lean after sustained WFO.

So, if you are still stock jetted with a 118 main, try going to a 120 or 122 and see if this stops.

My champ class buddy says they jet the trials bikes really lean on the main, so it will clean out and pull hard in section riding, but that same jetting is too lean for sustained riding on the main....

TY for the replies.

Yes I have water in the box, 5 hrs riding will add 1/4 window of fluid and turn the oil lighter.

I will replace water pump and see what happens.

I am jetted leaner on the main and richer on the pilot than stock, but can't remember the exact jets.

interesting Buckholz--- TY for your input. I may have two seperate issues, yours and a water pump seal.

The bike has never been hot enougth to peel the paint, so I am hoping the head surface is OK.

I will report back.