450r problems

[300ex mxracer]

on my 05 450r, whenever i ride for a while, it blows antifreeze out the overflow. it is not overheating because it does this in the winter too. i have the overflow line routed down one of the front frame rails and you can see the anitfreeze on the frame tube when im done riding. its not alot, but its noticable. any ideas?

[TheBlasterMan]

just because its doing it in the winter time dosnt mean its not overheating. In fact most people experience this in the winter due to the engine running leaner. (air is colder making it denser, more oxygen)

If your lean your going to want to increase you main jet size.

If thats not the problem.......

make sure your radiator is clean, and run engine ice.

Most likely not the problem but you could have a blown head gasket.

[300ex mxracer]

my jetting is spot on so im pretty sure its not that. it started happening all of a sudden during the summer. i thought about the head gasket but i figured it was along shot. is there a way to check it? maybe a compression test? also im running antifreeze/water and the radiator is clean. i wired the fan to run full time and it still did it.

[TheBlasterMan]

I honestly dont know what else there could be. Checking they head gasket may be difficult, i dont know if it will show up from a compression test. If its the head gasket it should be happening all the time while its running.

Give engine ice a shot, people have claimed it has lowerd their running temps by 20 degrees. I cannot confirm this but I have yet to get mine to boil.

[BSTURDIVANT]

Never fill your radiator all the way up if not running a overflow bottle! Fill it and run it hard for a while- let it spew out the amount it takes for expansion. Check your level after it cools- if no more than a inch, leave it alone and ride hard again. If it doesn't spew anymore out you have reached a level it needs for expansion.
If it continues to spew, replace thermostat!

[d3ktrix]

Originally posted by 300ex mxracer
my jetting is spot on so im pretty sure its not that. it started happening all of a sudden during the summer. i thought about the head gasket but i figured it was along shot. is there a way to check it? maybe a compression test? also im running antifreeze/water and the radiator is clean. i wired the fan to run full time and it still did it.

Are u running normal car antifreeze for cars mixed with water?
You might have it mixed too weak and the water is boiling/expanding too much causing it to overflow.

Head gasket is also every possible, or even a crack in the head. This happened to 1 of my local friends.

Whats your jetting?

[chevy400racer]

its cause its a 450!!! ha just kidding.... my buddy had antifreeze doing the same thing on his yfz450 and he thought it was his head gasket but when they pulled it apart the piston was junk and cylinder had waves in it.... so might wanna make sure thats not your prob.... but he was 375 pounds, (almost as much as his bike) ..

[hondaripper]

a compression should help you to find if anythings blown, i belive its supposed to be around 110 and 120 psi also if you overfilled the radiator that could cause it to blow out excess antifreeze

[TheBlasterMan]

compression test will read real low being an 05. The decompresser is active at low rpms (when your kick starting)

[300ex mxracer]

i do run an overflow bottle and i didnt swap the antifreeze before it started happening. i was racing in the summer and as i was looking it over after we were done i saw it were it collected dirt and i could smell it. i didnt change anything prior to the race so this happened out of the blue.

my jetting is 185 main, 50? pilot, and hrc needle 3rd clip. i have a rossier exhaust, k&n filter, and modified airlid.

my dad is going to bring a pressurizer and a borescope home so we can pressurize the cooling system and peek in the cylinder and see if we can see whats going on.

[300ex mxracer]

we let the pressurizer sit on the quad overnight at about 16lb and checked the cylinder with the borescope and nothing inside the cylinder so a head gasket is probably out of the question. any more ideas?