Just picked up a K75RT with some problems, gonna be night here now, then will have 1 day to fix, sleep, and have a weekend ride. (1500 km)

- Battery is dead. starts well with external battery, after 40km it's still dead. All electricity works (fine) , will replace with new battery, but might be cause of the problem (?)

- Starts well, but need very long time on choke. Last year it did the same, no change.
After choke off, it doesn't run smooth.

- Till 4500 rpm it runs "well", above 5000 feels like 1 or 2 cilinders missing. More throttle, sometimes more trouble, sometimes more revs.

- Fan not working, warninglight coolant does. Will check fan.

- Will replace sparkplugs, battery and fuelfilter first.

What else could cause the above problems?

Replace battery as you say.

Fan is common problem, there are more threads on this. There is a separate sensor for the fan. You can check if it rotates and is not seized, just turn it. You can also check if it works by taking a separate wire to it. If you do this and it works then sensor will be your problem. You can do an emergency fix by making up a manual override. If it doesn't work then fan may be your problem. You can buy motors but not in 24 hours.

Spark plugs and fuel filter good idea and best done before going any further.

Check for leaks on intake, but not sure what you can do in 1 day. If it needs choke is there an issue with injectors? Lack of fuel or lack of fuel pressure due to fuel filter or pump being blocked?

Got some spare parts in stock, besides 2 other K75's in shed (but they're in parts, won't make it in 1 day )
Been working on K's for 4 years now, but this problem is new to me   
Will check for leaks too, and check TPS for proper working.

If you habe spares then its easier. What about fuel pressure sensor? Some of the parts are easy to change. Have you old or new petrol in it?

:smoke:  Coffeebreak.

Petrol is new, pressure regulator have to check.
New sparks installed, X5DC, and a new fuelfilter.
Damn, the old one is....old. Not much flow in there anymore.

Filter; 22 euro
Sparkplugs; 8 euro/piece
Smelly hands; free  

Vacuumrubbers replaced, also coolant and fan (yep....another one), airfilter replaced, lots of little things, time to build up.
But, it runs well again   
Fuelfilter is really closed, think there's the main problem.
Oh, reardisk not straight, must replace too. And some bulbs.

Packed and ready to run  

Glad its running better now.

Safe journey and let us know how the trip goes for you.

Are you coming to Ireland ????

Thanks dude
No, not gonna be Ireland, maybe next year with my own bike.
Had to borrow this one because mine's not ready yet, first have to build my mancave.

This weekend will be in Germany, Harz
http://www.bikerwirt-harz.de/all-inkl-weekend.html

Hope you all can access the page, because many pics today of the renovation.
https://www.facebook.com/gerard.lejeune.737/media_set?set=a.798393993518242.1073741832.100000429472349&type=1
If not, tell me, will drag some pics in here.

We will go with a K1100LT (married couple) R1200GS (engaged couple, I got his K) and a K75RT (me) Pics will follow  

Just back to base,    and   
Saturday still not running well, but better than before.
Used injectorcleaner, 1/2 bottle/tank, 2 full tanks to use whole bottle.
First part noticed not much difference, but was only 35 km. Next came a 120 km part, getting better along the way, but still bugger. Fresh fuel and the rest of the bottle, and a little prayer not to ruin my weekend. Next 250 km problems dissapear and had a wonderful weekend with the K, now running like new   
Did 1300 km total, lots of 2nd and 3nd gear, 6000 to max revs, 28-36 degrees C, cooling stay ok, bit oil, tyres ok, and lots of fuel.

Will post some pics tomorrow, first get some sleep, , it's 02:35 night now  

Congrats with a "new bike"  .