k75 trouble
 

Hello all,

I'm new to this forum, it looks cool. Anyway, I'll get right down to business. I just bought my first motorcycle! She is a 1989 k75c with 25,120 miles on her. I bought it on August 2nd, and the first day it stalled and had to be push started. After that it ran fine for a few days. Then, yesterday (Aug. 6) I heard a clacking sound coming from the radiator and realized it was the fan. It was loose. So...I took off the tank and cliped the fan housing back over the fan motor, and put the tank back on. Then, this morning I drove it to work, and it ran fine, but...on the way home it stalled at a stop light and refused to start back up. At first, the engine was trying to start, but it wouldn't stay running. After several attempts, all I could here was the starter. Any help would be greatly appreciated. Oh yeah...it does have fuel, and I did have the kill switch off. Thanks again.

When you let the starter button go, can you hear the fuel pump running for another second?

Has this bike been sitting for a long time before you bought it? Fuel gone bad?

Is the battery good?

All k75 answers here
kbmw : Mostly technical discussion of BMW K75 &

Simon

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On the Kseries .. first thing - change the petrol filter .. it is inside the fuel tank. Second thing - unplug the etectrical connectors - clean them and put them back together.

Is the side stand switch still connected? Disable it...

After doing those things .. if you still have the problem then it will require some dectetive work to find .. get a multimeter and learn how to use it to measure dc voltage and resistance....

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You do need to service the bike - any 'new' second hand bike should get this from the new owner -

Buy a manual for your bike.. Hanynes make a reasonable one for the K75/100

Change the oils (including the front forks)
Change the filters - the engine oil one should be changed with the engine oil.
Wash the bike looking for loose/damaged bolts and nuts, damaged cables (electrical and bowden) and rust.

The above is a get to know the bike procedure. It helps to find all the things that might eventually 'go wrong'.

Update
 

Thanks to everyone for replying. One thing I forgot to mention is that the nuetral light stays on, the gear indicator only shows 4th and 5th gear and shows 0 for the other gears, also the clutch light goes on and off as well. I saw a tech page that said that this is probably caused by bad or corroded electrical connections. I will go through and clean all of them. Any other advice would be greatly appreciated. Oh yeah, someone asked if I could here the fuel pump going after releasing the start button; unfortunately, I haven't had the bike close to me for the last week, so I couldn't check.

The problem with the gear indicator and neutral light are almost certainly down to the same cause: the dreaded TGPI switch. Just a matter of a clean up - unfortunately it is a difficult one to access. The connection lies in the gear box behind the clutch and is only available when you take these off.

See here
Transmission Gear Position Switch Troubleshooting

However, if you have just bought a K bike then really you should be taking the transmission off to do a "spline lube". What's one of those? Well, you need to learn I am afraid:

K-Bike Clutch Spline Lube

K bikes need a bit of lovin' you see. Not too much, but in the right places.

Simon

Did the previous owner let the bike sit for a while before he sold it to you?

If so there are certain things you need to do in a certain order before you should even touch the start button...minor things....like dump the fuel and fuel filter...or else you risk killing the fuel pump. Follow what Simon, Beddist and Frank have mentioned so far...including checking for corroded grounds...


If this is a new problem on a previous running K, then we'll need more data.
Also there is a Kbmw yahoo group that offers fairly good technical advice aside from what Simon and Frank have offered.

The worst thing you can do to a K is let it sit...;(

Got the bike back!
 

Hello all, thanks again for the replies. It turns out the problem was a result of a few things. (1.) when I turned the bike on, the fan would turn on, which put a burden on the battery. And that brings me to the next problem. (2.) the battery is smaller than the recommended size. (3.) and third, the fuel cap assembly does not have a drain hole which was allowing some water to enter the gas tank. This is still a mystery to me. Why is there not a drain hole/ If anybody knows pass it on to me. Thanks again.

Joey

I'm afraid this BMW clutch spline lube thing is a red cloth to me. Seriously: BMW says in all its manuals that this has to be done once a year and all after-market manuals repeat this as gospel. Interestingly, the routine maintenance prescribed doesn't mention it. This leads me to believe that is a BMW legal cop-out: if we fail to apply sufficient grease in the factory and there is a problem we will not cover this expensive repair under warranty.

Who would buy a car on which the engine or gear box has to be removed once a year? Same technology. If it ain't broke...

Are we talking about the same shaft here?
 

Hi mate. Are we all on the same page here? I have owned a number of K-series bikes over the years, and one destroyed it's driveshaft internal splines about 3 weeks after I bought it. Ok, it WAS about 12 years old and by the look of it, the splines had never been greased, and I was riding the nuts off it at the time, but it's still something that should be done as regular maintainance. It's actually very easy to do.

Bike on main stand, back wheel off, diff off (up to eight bolts now), pull out driveshaft. Grease inside both ends of the driveshaft, slide back in and swear a bit as you try to get the gearbox output shaft and driveshaft to mate together, diff on after replacing oil, wheel on, ride.

Regards

Nigel in NZ

That is not normal! Either the fan relay or the temperature sensor (or the wires) are faulty .. of someone has wired in a switch .. that needs to be turned off.

... So ...

There is a drain hole .. on the left side ... open the cap and on the left side before the ridge where the 'cap' goes down there is a hole .. it exits on the bottom right of the tank .. along side the overflow/breather... It commonly gets blocked with crap...

photo of inside of fuel tank ..located here ..

http://www.geocities.com/fwarner_au/...tankbottom.jpg

Once fixed - change the fuel filter.

No we aren't, Nigel. He was pointing to the clutch spline lubrication, which BMW says has to be done every 12 months on all flat twins and Ks and requires separating engine from gear box. I think this is nuts.

I agree with you, the splines on the drive shaft should be greased, but if you have a lot of grease in there then you won't have to do that very often, either. I've got an old K100RT sharing a rented garage in Rotorua with my old R75/5. Can't remember whether I ever had the drive shaft out.

Oh the good old days when it was all running in oil... Honda, on the other hand, put grease nipples there.

There are two era's or K bikes...the Klassic K's and the newer K's. Their respective issues are unique to each era.

THe Klassic K's had splines that were weaker near the final drive. Between the transmission and the final drive are two sets of splines: the clutch splines and the final drive splines. In between these splines is a driveshaft depicted in the illustration below.
Driveshaft is part number one...it attaches onto the input shaft coming from the transmission at one end and the other end, it attaches to the final drive...pictures in the second link below.
RealOEM.COM * BMW K59 K75S REAR WHEEL FORK MOUNTING PARTS

RealOEM.COM * Part Category Selection

The splines that need more attention are the ones at the final drive end. They need to be cleaned and greased every rear tire change.

The splines at/near the clutch end are fine and need to be cleaned and greased every 40k miles or so.

The clutch splines RARELY see a failure, but the Final Drive splines usually do for various reasons. BUT this is not to be confused with a failure of a Final Drive...a rarity as well.

The Final Drives splines are a known issue on the Klassic K's but they usually hit the owner around 90k miles. BMW messed up this design and should have put in grease nipples in both places to facilitate greasing.

Driveshafts and final drives exist in many vehicular and non-vehicular applications that there were many "best practices" designs that could have been learned from by the BMW engineers.

Honda I think has gotten it closer to right than BMW has...and it shows on their newer shaft driven bikes.

Ahem, by my definition the clutch splines are on the gearbox input shaft and the clutch plate sits on them. This is located between engine and gear box, nothing to do with the drive shaft. This is car technology. This is the one that BMW says needs to be greased annually and requires separating engine and gear box. My /5 manual from 1969 and my K100 manual say so. However, it is not in the regular maintenance schedule. Go figure.