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07 KX 450 runs really HOT

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Just wondering if you guys have any feed back on my bike running so hot. I almost always have coolant coming out of the overflow line. I was thinking of trying a boyesen supercooler , but they are not cheap if it doesn't do anything. I also thought of try a JD jet kit, I heard that it might help my temp. problem.

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also besides the jetting the coolant on these bikes seams to like to be right at the top of the fins.How much coolant do you lose and where do you top it off at? And does it lose it below the fins or gets to that point and stops?I'd check these Two things out and then start thinking about a possible head casket or exhaust leak.

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Yeah as already said, don't assume you need some special after-market cooling solution. Something has to be wrong with your bike (like jetting or coolant flow or something). eg. In our Sydney summers, I've ridden in some pretty hot temps and at lowish speeds, and been surprised what I got away with. Never boiled it to date. No fancy coolant. I did put in the alum 'Y's as soon as the 07 parts came out. In warm weather, my jetting is slightly rich all the way thru which has to help. I have always used a tiny Fuelstar TM-VC unit in my tank which is great for crisp low RPM torque, and maybe the cleaner burning helps keep temps down too. Maybe. :thumbsup:

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Overheating is not an issue with these bikes unless there's a problem or it's left running with little or no air moving though the radiators. For jetting problems to make it overheat, I would expect other problems too (i.e.: backfiring, trouble with cold starts, etc.). Make sure you never leave the bike idling, even for just a couple minutes.

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hey those boyesen pumps are awesome you can get one for about 169$ but i have also drilled holes in my rad shrouds and my bike seems to run great hope this helps you

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My bike runs awesome. No hard starts, no bogging, only when it is really hot (+30*c) I have to turn the fuel screw a 1/4 turn. The spark plug is a perfect brown, so I don't think that it is lean. I'm a fast intermediate rider but not a pro, so I don't rev the crap out of it. I just rebuild the motor and all is good. I almost wonder if I'm just filling it to full, but I don't think so( a quarter inch above the fins). I was wondering if you guys have had any coolant out of your overflow tube.

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In summer, my coolant pushes out thru the overflow until the level (when cool again) is about 1" to 1.5" below the cap. Then it generally stays at that level. So I don't bother topping it right up all the time.

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I used to strees about this alot cause I've always got coolant in my overflow hose. I always think the rad's are going to be empty but everytime the level is just above the first layer of fins.

So now I just trust in Kawasaki and ride it. I still check it often though.

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Maybe I'm stressing about it to much but when I just checked it the fluid level is just below the fins. I had to tip the bike over alittle to see the coolant level. If it is the jetting, have any of you guys used a JD jet kit. I have talked to a few guys that ride KTM and they swear by it. The jetting is way richer on the main jet and has alot different needle.

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Engines are supposed to push coolant out if filled to the max. As all that aluminum in the head and cylinder and the rads themselves heat and expand they squeeze coolant out. It's normal. The cap pressure is to increase the boiling point of the coolant to stop it from actually boiling, it's not meant to stop the excess created from expansion from exiting. When the engine cools and shrinks again it draws in air... and when you start the bike up again it expands again and pushed this air out and once again the rads are full.. while hot.

Overflow bottles in cars and street bikes catch this overflow and when the engine cools and shrinks.. instead of drawing air back in it draws the expelled coolant back in.... only to push it back out every time the engine comes up to temp.

Actual over heating will cause the coolant to boil.. that you will most certainly notice. That's when you know it's running too hot and something is wrong.

It's nothing to worry about and is perfectly normal.

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I've never boiled" mine, and my coolant level has never gone below the fins. If topped up it always pushes some coolant out. I am confident after last summer here (and some serious mud riding in the past 2 days), that the stock and healthy KX450F cooling system can handle a good dose of heat. Yep, if mine did go below the fins, I'd be trying a new cap or getting mine tested.

Yep, I agree, always important to check oil and coolant levels and colors before every ride.

If anyone is keen/curious, on ebay you can buy little temp rating "stickers" to put on your radiator.

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