K75 Overheating

Things to check for an overheating K75

From the BMW list:

Date: Thu, 13 Apr 95 18:01:07 MST
From: Rob Lentini
Subject: BMW: Re: Art Jacobson's Hot Ks

Art: It is unusual for K75s such as you and Katherine ride to get so hot to the touch, as you report. Things to check:

1. Verify operation of the cooling fan. Start the bike up and let it fast idle until the fan kicks in--about 10-20 minutes depending on outside temp. These fans are known to seize up and burn the commutator brush assembly. Clue? Your horn doesn't blow because the fuse that powers it and the cooling fan is blown due to the seized fan.

2. Change the fuel filter in the tank. A plugged filter will slow down (eventually stop) fuel flow and overheat the fuel in the lines and fuel rail, giving you the "boiling" sounds you hear, and will eventually cause vapor lock.

3. Install the foil-like heat insulator blanket on the underside of the fuel tank. Common on K100s, many K75s didn't come with it.

4. Ride faster!

Rob Lentini
'87 K75S
Tucson, AZ

From: joe@mpd.tandem.com (Joe Senner)
Subject: Re: BMW: K-Bike Overheats!
Date: Wed, 31 May 1995 10:28:57 -0500 (CDT)

]I heard a muted "pop" and noticed steam rising from the right side
]of the bike and hot coolant running down my pant leg. I pulled off
]to the side of the road and as I did so the "hot" idiot light 
]came on for the first time. There appeared to be about a quart of
]coolant in the road....
]pressure-relieved itself. Now I'm not so sure...why was the overflow 
]cap seemingly blown off, especially considering that it's got a vent hole? 
]Why no idiot light until AFTER the incident occurred? Any theories here?
you've probably gotten a bunch of answers to this already, I'm so far behind in my mail, oh well, I'll pipe in anyway.

things to check:

one thing to remember about K bike idiot lights is that the sender for the light is mounted near the bottom of the cooling system as a whole. this means it's going to get a reading from the coolest point in the system. the other thing to remember about idiot lights is that they are just that, idiot lights, and are simply a guide. knowing when your fan should be on and isn't is a better warning system.

Joe Senner

From: "keith (k.p.) hanlan" <KEITHH@BNR.CA>

I just wanted to one more item:

[FWIW- I had mine replaced under warranty - wd]

Thanks for the service you are providing.
Keith Hanlan KeithH@bnr.ca Bell-Northern Research, Ottawa, Canada 613-765-4645