BMW K100RT - Starter Relay fix

[pfetter]

I understand that the starter relay is under the gas tank, I have a clymer manual which I find very vaque. The problem I have is the battery was low and tried to start and now that I installed a new battery, as soon as I hook up the negative cable the starter starts turning. I think the relay is stuck together. It says I have to remove the gas tank to get to it. In order to remove the gas tank I also have to remove the left lower fairing and the small storage area on the left but that is where the radio is installed. I cannot find any information on removing the radio and disconnecting the wiring easily. Any help.

[kioolt]

The radio wires have plugs underneath the radio slide in bracket. Due you have the radio removal tool?

[wndsrfr]

You only need to lift up the back end of it a bit. Getting to the fuses under the tank doesn't require removing any fairing parts on my K75RT, and I think it's all the same on a K100.

I do remove the "glove boxes" and on yours with the radio you'll need to get under the cover plate to remove the screws holding the "glove boxes" in and lift them out.

I'm betting that the radio has slip connectors that you can unplug easily to get your left box out.

After that, raise the seat and pull the tool tray back a bit and you'll be able to see two little clips that hold the rear of the tank down. I use needle nose pliers to pull these rearward while holding a little pressure down on the rear of the tank. (It's easy to drop them, so it's a good idea to have a clean, level floor under you.)

Next you'll need to unplug the wire on the right side of the frame that carries power to the fuel pump--it'll be easy to spot as you lift the rear of the tank since it'll be what is holding it from moving up easily.

I then wedge a small piece of a 2x4 under the right side of the tank to hold it up off of the fuse box.

From there you're good to go----whole process takes about 15 minutes with practice and it's good to know how to do it!

[PGlaves]

The starter relay is in the back right corner of the electric box right at the back of the fuel tank. It has 2 large wires which bolt to exposed connections visible from above the relay box. If you raise the rear of the tank about 3 inches you can get a short nut driver in to remove those two bolts, and one more that holds the relay in place. They are either 7mm or 8mm heads - I'm not sure which anymore.

[pfetter]

Thanks for the information concerning the radio and getting to my starter relay, now the next question, does anyone know of a retro relay that BMW came out with that helps fix the problem with these that weld themselves together. I saw on a site somewhere that one was available. Also has anyone taken one of the sealed ones apart to try and clean the contacts or do you just use the "rap with a screwdriver" method to unstick the contacts and hope it works. I had also thought about actually relocating it just under the seat so it does not require so much work especially if you are on the road.

Thanks for the help everyone is very helpful.

[cjack]

Thanks for the information concerning the radio and getting to my starter relay, now the next question, does anyone know of a retro relay that BMW came out with that helps fix the problem with these that weld themselves together. I saw on a site somewhere that one was available. Also has anyone taken one of the sealed ones apart to try and clean the contacts or do you just use the "rap with a screwdriver" method to unstick the contacts and hope it works. I had also thought about actually relocating it just under the seat so it does not require so much work especially if you are on the road.

Thanks for the help everyone is very helpful.

There is a BMW retro kit meant for the K12RS and LT ($211.00) which could be used, but most usually replace the stuck relay on K100 with a same new one. The relay is not sealed and if you carefully take the top off, you can unstick the contacts. I have unstuck them at rallies, etc. by tapping on the starter button with the ign on while the starter is turning. You have to be quick about it. I think energizing the relay coil causes enough mechanical jolt to the contacts that they flex and release. This has been a somewhat permanent fix when it works...unless you let your battery get low again. There is usually not a significant amount of weld material on the contacts so the unstuck relay seems to often work well afterwards.
Jack Hawley

[kioolt]

It's not a big enough problem to warrant relocating the relay or in my opinion replacing with a different one. In the 120K miles that I have had my K100LT the relay has only stuck one time. I raised the back of the tank and tapped it and never have another problem with that relay for the next 15 years.

[CustomSarge]

After the third different bike did this on a season opener check ride, I got REAL sick of the low battery fear. I have a solid state relay in my K11LTX going into its' 4th season.

Disclaimer: I designed/built it, tried to market it, found the "purists" completely nonplussed on advantages vs non-OEM origin. 2FB! If somebody wants one they can PM/email me & we'll "talk" (I've sold 2: not exactly an empire staple). L8R <<<)))