Hi all... I'm new to the forum and was hoping for some advice on a Brute Force overheating issue. I bought it brand new last month and have taken good care to ride it right.

My 2007 650 Brute Force straight axle overheated today after a very short and mild ride. I've only got 9 hours on the machine and about 80 miles on the odometer. I've gone on 5 trail rides to date, some on very hot days and it never once got hot. I've not had it in deep mud and I don't think there is any obstruction in the fins of the radiator. The last ride was a week ago... real rocky, real hot day, couldn't go over 15 mph and it never even hinted about getting hot. So, here's what happended today...

A buddy and I set off on a trail ride. We've gone about 4 miles. The speeds ranged from 15 to 50 mph on this route. I'm leading on a slow path at about 15 mph and he flags me down from behind to say he smells antifreeze. So, I stop, just as a cloud of steam comes out from under my front fenders.

Hmmm... that's odd... my temp light didn't come on... and neither did the fan... or at least that I could hear while wearing my helmet. I know the fan worked before, 'cause I've heard it... just not today. To be honest, I've not lugged the machine enough for it to come on. So, I shut my machine off and start looking for a leak.

The antifreeze ain't hard to see. It's exiting the bike in two places... one, at the overflow hose under the left front fender, and two, out the cap on the coolant reservoir. The antifreeze came out with a ton of pressure pushing and spraying coolant with enough force to push it past the closed plastic cap on the reservoir. You know, that semi-transparent cannister with the coolant level lines on it by the left foot peg? Yeah, that one. Not cool... no pun intended.

So, as I'm sitting there... the fan comes on. Remember now, the engine is off, and has been for about a minute. WTH? Little late there Mr. fan... thanks for nothing. I'm steaming as much as the bike... the dealship is a good hour from where I live and I've already had to take it back once for a battery replacement.

Back the issue at hand... I'm thinking thermostat... but where the hell is the thermostat? Does it have one? I can't even find the radiator cap under all this plastic. All that pressue had to build from somewhere... it ain't just your average, "damn, I ran 'er too hard" loss of coolant issue. Matter of fact, I've purposely not run this bike hard. It cost me major dead presidents and I got one lousy hour before the manual says I can run it like I stole it.

So, I opt to let it sit and cool VS. taking the ring temper out of my almost broke in machine. I'm not real happy about it, but at least I can hop a ride with my buddy on his ATV back to my truck. We double back and fetch my BF home.

Now, after reading some posts here about why BF's get hot and puke, I'm really not certain why mines being a jaded girlfriend. It ain't like I was riding a stripper and got caught... 'er, I mean a Honda or sumpin.

The last ride before today was dusty... so said my air filter when I cleaned it... but I'm willing to bet that the pressure I saw pushing coolant past the reservoir cap today ain't coming from dust in the rad fins. Hell, I've been wrong before... but I must say this machine hasn't been mudded, pounded on or abused.

I hoping for some ideas... and with many thanks in advance, Os.

 

The first place I would go is the radiator. Make "SURE" it is clear. You would not be the first one that came on here and says that you think the radiator is clear. The only way to be sure is check it by sight.

If it is clear then the next thing I would suspect is the fan temp sensor. If it came on that late it is fubared. The thing may work, but come on too late to do any good.

There is my two ideas. Let us know what you find out from the dealer.

 

Sorry, I dont have any advice but by any chance was the person you were riding with Ricky? He told me this exact same story about somone he rode with.

 

Hi Bud,

I would check:

on the non-throttle side of machine front tire area...Inside of tire is the plastic protection, remove the 6 screws with phillips head...

then remove plastic cover

u will see the side of the radiator, on top is the fan sensor....make sure the wires are crimped on...Mine were not, after 200 miles it started over heating...Fan sometimes worked and sometimes not..Those two wires slide right off...I pulled the wires off and crushed the crimp 1/2 way and slid them back on and worked beautiful since.


Since you have it exposed, wash out back of radiator also...


Then drive it like u stole it


TK

 

Allrightythen... much love for the replies, yessir. Drum roll please, as the smokin' hot verdict is in!

DING! Todger wins the prize! Here's why...

Exactly, and I do mean exactly, hey, did I mention exactly? As he described in his post is what I found. To the letter.

The wiring issue on his BF fan sensor switch was what I found on mine. The sensor was easy to get to, as were it's two wire contact posts. The ill fitting push on connectors allowed dirt to enter, which was baked on the posts. This only helped to further accelerate a fan malfunction. Remember, this buggy only had 9 hours on it when it puked green. Now THAT pisses me off.

WTH? So much for quality control on that component. Hell, its job is just keeping the engine cool. No biggie. Hey now, how's that yellow diff-lock rubber lever cover dooflickee looking Bill? Good, real good. We put 'em on all our $6K and up machines. Sweet.

The real problem was with the inboard spade / bullet connector. It wasn't fully disconnected, but it wasn't making a good connection either. A light touch and it just slid right off the post.

The outboard connector wasn't far behind the inboard. I followed Todger's advice to fix it and added a couple tweaks of my own. Since the dirt got baked on, a soft brass brush, (like a toothbrush, made for cleaning firearms), served to remove the film. A .22 caliber bore brush chucked up in my cordless drill worked to stake any film from inside the female connectors. Introduce electrical silicone based diode grease to the unions and we're back in business.

So, I changed the oil and filter just because I was there... loaded it up and headed for the same trail it steamed on. I lugged it around for a good while just to be certain... daring it to **** the bed. It didn't. The fan worked flawlessly. The odo timer hit the 10 hour mark during this trip. Only fitting that I got to run it like I stole it. The engine never once offered to get hot. Not even close.

All for a couple connectors that should have never been allowed to leave the assembly line. Man, that fries my bacon. On a side note, I chose to remove the rear most inner plastic panels from under each fender well. Not the larger main sections that help divert debris away from the radiator. The ones closest the front of the engine. I understand their job... but they do nothing to aid in cooling. In fact, they deter it. Before you say, "you'll have a muddy engine"... I have a hose and I ain't afraid to use it. LOL. Have a peek at the 2006 "i" models. They have an even more open air design. Mine will be similar... 'cause IMHO, excessive heat just plain sux.

*HATS OFF* to all who replied. Much appreciated!

 

Glad it worked....Exact same thing happened to my machine last weekend....

TK


Tamiyacrawler - I rode with a guy who's last name is Rickey in WI this last weekend

 

First off I'd like to vent and say that a bike this new and overheating is B.S. I guess it's gonna take a lawsuit to get Kawasaki to fix this crap and design it right, like with a bigger radiator that doesn't run on the ragged edge of overheating. Let alone the EPA rules made the bike run leaner by law, which is hotter. Performance is awesome, though.

On the 750, The thermostadt is located on the right side of the bike just under the upper frame tube. It is not ON the engine. (<u>not sure if the 650 is the same, but it's easy to check</u>). There is a steel tube that runs to it parallel with the frame and is sealed with an o-ring at the tubing end. From there is the thermostadt housing and the hose that goes to the upper right of the radiator. There are no gaskets, just o-rings to seal it. Very nice. Remove 3, 8 mm bolts from the top of the housing and the thermostat is located under that. One bolt is used to hold the tube to the housing. Remove it if you need to remove the housing.

There are weak points in the cooling system. The fan switch, the thermostadt, and the radiator cap. And lastly the radiator or fan could be bigger. The fan switch is pretty fragile and easlily corroded and unhooked. There are no tabs to hold it on. So the crimp idea above is good. But I'd additionally add dielectric grease to the terminals to keep them from corroding. Mine were corroded and melted the silicone boot on one of the wires, it also tripped the breaker.
Like most cooling systems, the radiator cap is the sole device used to keep the system under pressure. If it is weak, the system will boil over. 15 psi min. Why yours is leaking under the front fenders is a mystery. The only place the coolant should be going is to the bottle. When the bottle fills is when you have coolant steaming out. Check for leaks and that the good cap is on tight.
I personally don't think the thermostadts are all that good. I tested mine and it was supposed to open at 71 degrees celsius. It finally opened at 81 degrees celsius. And I've only got 50 hours on my Brute.
Use a light behind the radiator to make sure it is clean. Very clean. Clean it again! Clean it from the back, too.

 

I cant beleive I probably just found the fix for my buddies Brute

Thanks Todger [img]i/expressions/beer.gif[/img]

 

4x4wazz - let us know how it works out. If not, we will give you more things to check


TK