Hey all,

I'm looking for a 1984 K100rt ECU (the one under the seat)

I recently pulled the gas tank off to fix a leak. Now that it's all tightly sealed, I haven't been able to start the bike. 
I've been through [url=https://bmwmotorcycletech.info/K100 troubleshooting Starting.pdf]Bert's Guide[/url] and have the same exact symptoms as the very descriptive GeorgeW50. So I'd like to look for an ECU.
If you have one or any leads on where I can find a working one, please reach out, at tkrazy74.5@gmail.com or 530-414-9892 

Alternatively, if you have an 84 K100 that I can test my ecu on I'd be very appreciative

I'm located in Berkeley, but work in SF so any where along the way can work for me


Best
tyrone

As required of new members, please make an introduction in the Member's Intro page, and then good luck with finding an ECU for your machine.
Cheers.

It's part number 13 61 1 460 950, superseded from 13 61 1 460 449 & 13 61 1 461 828 (Bosch 0 280 000 313) and fits all 8V K100 models from start to finish, and if not from a member here, readily available on eBay for under US$300. Tho' I've seen 'em heaps cheaper than that.

Check your connections, not sure why you unhooked the Fuel Injection Unit, under the seat but you can install it wrong and it will blow the lowest fuse. It looks like it is hooked up properly but it isn't in the right location.  Also the connection just below the tank on the right ( connection that goes to the sending unit on the bottom of the gas tank) has been known to cause problems.

I'd check these out before I purchased a EFI unit.

I shouldn't worry about the ECU - they almost never fail.

Oh hang on....

The four pin connector for the tank is a notorious source of running problems.  It can be cleaned and the sockets tightened.  Many have given up and replaced it to get a reliable connection.

tk74 wrote:I've been through Bert's Guide and have the same exact symptoms as the very descriptive GeorgeW50.

In support of the posts of Point-Seven-five and cycleman, there is an important sentence in the Guide's introductory text:

First, you have done all the basic troubleshooting such as: checking the fuses, ignition switch, kill switch, side stand switch (not applicable on early K100), transmission in neutral, clutch in, starter connection, Fuel pump connector on the fuel tank, and battery connections.

Determine if you thoroughly checked all those items; including the one highlighted in the text. On early models like yours it is located beneath the fuel tank's left side. Shifting or removing the fuel tank can affect the integrity of wiring and electrical connectors, including the fuel pump connector, and might affect the fuel pump's fuse. All electrical connections should be cleaned with contact cleaner.

Please give us an update.