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

I recently bought a Spal 6.5" puller fan from Jeep Specialties, cost $60 plus $15 to ship. Price has gone up ten bucks but it's still a great deal compared to some alternatives. It's going in my 94 1100RS soon.
https://jeepandtruckparts.com/products/spal-325-cfm-6-5in-fan-push-va22-ap11-c-50s?variant=43733792227571&gad_source=1&gclid=Cj0KCQjwltKxBhDMARIsAG8KnqVaGvFJpGVO4_MocuxjJkE6eYtIPNAhkQdlv0J3Wh9uBG3J0HsoATsaAvdLEALw_wcB

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.

 

My experience:
Kneading 30 year old rad hoses repeatedly is not a good idea.
You could end up like I did 1,000 miles from home:

Some people get carried away when kneading. You're lucky you didn't get a rash, too.