radiator spillover

[Blue_Balls]

My bike has started spitting coolant around the rim of the radiator cap. I bought a new cap and made sure the line to the overflow reservoir flows properly. That seemed to help some but not completely. I do see coolant move from radiator to reservoir and back as she heats up and cools down. It still spits at me when I run at sustained mid-to-high revs. I am riding in 90 degree weather during the summer.

I'm suspecting a compression leak in head gasket. Does anyone have any other ideas? How do I confirm the diagnosis before tearing into the engine?

[YAMAKAZE]

Before you go rippin the head off looking for a bad head gasket, check out a couple more things.

First, is the fluid being transfered back to the tank filled with bubbles....How about the fluid in the radiator...any small droplets of oil floating around in there? How about the radiators themselves, clear and free of debris trapped between the veins? How about the Waterpumb impeller....Have you removed the cover to ensure that the impeller doesn't have a broken fin? How about that Cap....Did you replace it with a 16 lb cap? anything less and your gonna overheat in 90 degree weather, especially if your idling for any amount of time or doing alot of slow tight stuff with no air crossing over the rad.

If you had a blown head gasket it would manifest its self either thru the exhaust as a white cloud of smoke or in the rad it's self as oil droplets or anti-freeze turning into foam from the air injection.

Also, you may want to drain and replace the anti-freeze with a product designed to handle the hot temps better such a s watter-wetter or Engine-Ice which I use and it does a great job....

Good Luck

Bonzai ?

[Blue_Balls]

Thanks for all the good suggestions Yamakaze. I have not seen any signs of oil droplets in the coolant or small bubbles/foam in the reservoir hoses. I don't see vapors in the exhaust. The radiator has taken its share of bumps, but cooling fins are not clogged and it looks clean on the inside. I am using a 16 lb rad cap from an automotive store.

I think I will try the water wetter. At the same time I'll take your advice and check the water pump impeller. But it seems like if it was overheating it would simply continue to fill the reservoir instead of blowing out the cap.

Thanks again.

[S_Phillips]

other alternatives:

how is your jetting? make sure you not running that thing way too lean.

check the oil level, and see if there is water mixing in the oil?

make sure the area behind the raidator is clean as well, air has to have room to escape after it comes through the radiator. if there is debris clean it out.

[Blue_Balls]

I flushed the radiator and replaced coolant with Engine Ice. In the process I noticed the filler neck was a little oblong leaving a couple of "high points" on the surface that the cap seals against. I straightened it, and had no further leakage after riding for 2 hours in 94 degree weather.

Thanks everyone. I'm sooooo relieved to be back to normal!

[phrog03]

Check and make sure of all the obvious could be problems but my guess is you need a 1.8 radiator cap. I is sold by Kawi If you run into problems E-mail Ty Davis at his web site and ask for the part number I spoke with his Mechanic and He gave it to me. It help me in the Heat.