1985 BMW K100RT won't idle

[pinhead]

My K100 won't idle when its warmed up.  I have turned idle adjustment all the way up and doesn't help.  Any suggestions what the problem could be?

[The Mighty Gryphon]

First thing I would look for is an air leak.  The crankcase breather tube(AKA "Z" tube) or the bushings above and below the throttle bodies are usual culprits.

Another possibility is a faulty coolant temperature sensor. 

There is information on how to check these items here at the forum.

[pinhead]

I changed the coolant temperature sensor a few weeks ago and no improvement.  I replaced that z tube last fall.  but no change .....

[frankenduck]

My first guess is throttle body boot(s).

https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/tbleak/tbleak.htm

Part 11611460408

They "only" cost $61 each these days and you want to replace all of them so you're looking at $244.

Would I pay that much? Not in a million years - because a I have both Swedish and Scottish genes trying to out-cheap each other.

The last K75 that I bought had a bad TB boot. I paid less than $30 shipped for a used set of three on Ebay - knowing that I could return them for free if I didn't like them. Turned out that they were in great shape so I gave them a 303 bath and installed them.

https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/k75pa.rehab/k75parehab.htm#fuel.rail

[Bmwsquirl]

For boots try a company called siliconeintakes.com
Squirrel

[pinhead]

thanks all!  I am going to do that propane test for leaks and see what happens.