03 crf 450 rad overflow

[b1rcyu76]

i just got a 03 crf 450 and was going out to go riding, but when i was warming up my bike i had left it idle for maybe about 10 -15 minutes and my rad started to release antifreeze and steam. I was wondering if the rad was overflowing because there was no air flowing through it. It only happen twice and while i was sitting. I have never had this happen on my 2 strokes and wondered if I left it run in an idle state to long.

 

[bclapham]

the thumpers run hot, but you arent doing yourself any favours by letting it stand while running. for the rads to work the bike has to be moving to get air over them.

i know people that have also used higher pressure rad caps to stop the boil over

 

[DEANSFASTWAY]

Some of the nice enduro guy thayt ride in the woods will take a small brake fluid bottle and make a catch can for the coolant and it keeps the bunnies and groudhawgs from tripping out and bumping head first into the trees, the liquid XR 650 couldnt live without it. Shut it off when you stop for a ciggy break too.

 

[Tony Eeds]

Good advise by everyone. My 400 overheated while I got dressed at Moonrocks in February. I thought the dang thing was on fire for a minute. :|

 

[DEANSFASTWAY]

Thats really bad you know. When newer YZF get hot they have a little rubber plug on the RS of the cyl head that covers the hole for the old decomp lever . They get hot and the rubber gets real hard and the pop out or leak . Saw one on fire one morning. Speaking of fires my friend had a early YZF 400 that had a gas tank leak and it leaked on the coil that used to be next to the kickstarter . the bike lit up in the woods so he panicd and pushed it into a creek to put it out , then it was a black and blue bike .

 

[GREENBEAN]

I use a product called water wetter it is what the road race guys use. I use it in my truck too. it really brings the temp down 10-20 degrees I just keep adding it when my radiator gets low so there is maybe 6 or more ounces in there now. You can use just water and wetter at 50/50 the recommendation is on the bottle. I havent boiled over yet with it but I would have to say 15 minutes and it would that is way too long to idle a high performance thumper maybe a three minute warmup is all I do. I have a high pressure cap on my wish list I think SRC makes them.

 

[PeteN]

The CRF already has an overflow bottle built in, the front frame down tube! Just drill a small hole about 1" up from the bottom weld and tap for a small fitting, attach the tube coming from the radiator. Drill and tap another near the top and it becomes your overflow. There is also a small vent hole about halfway up the back of the tube which will need to be filled with JB Weld. Use the tube from the rad to fill the frame with a couple of inches of coolant and your set. This system works very well, keeps your radiator full, and eliminates the drips and steam. FYI

 

[tnrider]

my 03 does this too - i bet all modern 4-stroke racers will too - don't let it idle too long AND always top off the tank between rides. I will even check after lunch break and top off again (make sure it has cooled) - slow trail riding with young kids for a day will dump about 1/2" out of my radiator - this includes numerous "catch up" waits with engine running.

i have not yet tried any of the non-factory radiator solutions as you must drain the radiator first and i am just too lazy to do right now...