BMW K100 max speed 85mph

[Ruben92]

Hi Guys,


First of all i learned a lot because of this forum, thank you all!




Today i was driving on the highway and i couldn't get it faster than 85mph +-.
Also lost a lot of energy on accelerating..


My guess is that it only runs on 2 cylinders?


Already checked:


- Sparks (all 4 sparkplugs fire).
- Fuel in the hose, rail.
- Sprays fuel through the injectors.


Someone who has the knowledge to fix this, let me know! :)

[Chaos]

was it cutting out or missing when you tried to go faster than 85?  if so first suspect would be fuel filter.  Your top speed will steadily decrease as the filter plugs up.

[Martin]

What do the spark plugs look like? What is the condition of the air cleaner element? When did you last change the fuel filter?
Regards Martin.

[Ruben92]

Thanks for the fast reply.

I maxed out the gashandle and it felt/sounded like i was trying to cruise on that speed.

Spark plugs are in good condition (changed them last week and have a good color).

Air cleaner element is clean and there is not escaping any air.

Never changed the fuel filter.. so i will get a new one.

The K100 has had some problems and this is the first time in a year that it started. Could that have clugged the fuel filter?
I also added some injector cleaner in the fueltank.

[Martin]

Change the fuel filter then let us know.
Regards Martin.

[Ruben92]

I will!


Thanks so far.

[K1300S]

have you done a COMPLETE baseline tune up?  have you checked for torn intake and vent hoses?  vacuum leaks at TB boots?

[Ruben92]

Checked all hoses and also tyrapped every connection.


I will get a new fuel filter today and let you guys know!

[Ruben92]

Sorry for the delay guys, had to order the part and i couldnt get the screws out.


Date on the old fuel filter is 14/07/09  :clap:


Will put the new one in now, i'll keep you guys posted!

[Ruben92]

Filter is placed. Battery needs to be charged more to start unfortunatly.


What i also noticed is that the fuel pump is contantly pumping, while riding.


Changed all the cables for a new set so maybe i connected it wrong? (Not using the connector anymore and i think these cables are from a different year cause of the different colors) Spare fuses are almost all blown so maybe someone knows how to connect it correctly?




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[Laitch]

Changed all the cables for a new set so maybe i connected it wrong? (Not using the connector anymore and i think these cables are from a different year cause of the different colors) Spare fuses are almost all blown so maybe someone knows how to connect it correctly?

Which cables did you change? Which connector are you not using? Type the last text in your post differently so some of use might read it more easily. Please supply photos of the connector and cables you have mentioned.

It's ok for the pump to run when the bike is running. You won't hear it as much if you keep the tank full of fuel and wear earplugs. Just be sure it is the pump that you are hearing and not the fan.

[Steenbeen]

Did you just bought the bike? I had the same problem once, when I first got my K. Check this thread: http://www.motobrick.com/index.php/topic,8682.0.html. It turned out something blocked the throttle and I couldn't fully open the throttle. Very simple, but really easy to overlook.

[Ruben92]

Sorry for the delay, had troubles starting the bike.


The bike was leaking oil, fixed that.
Also there was way too much oil inside.
Changed the oil for new oil and put the right amount in.
Bike starting to go faster everyday and begins to have more horsepower.


Still, this is nowhere where it should be.


My guess is that there is oil in places where it shouldnt be?
Found some oil inside the airfilterbox, so im cleaning that out now.


Throttle is not blocked, thanks for the idea.

[The Mighty Gryphon]

My K100RS sat for several years before I got it.  While not as bad as yours, it was not even as strong as my K75's.  I had been running Techron through it from time to time slowly getting better performance and now, about 8,000 miles later it finally has come into it's own.  I can specifically remember the spot where I was riding last summer and suddenly had the engine feel like it got an extra 15hp. 

I had the same situation with a truck about 25 years ago.  Took it about 5,000 miles to get it running right. 

I suspect that in the case of my K100 part of the lack of power was stuck piston rings that weren't giving the full compression the engine was capable of.  The engine used a bit more oil than it should when I got it and as performance improved the oil consumption has also dropped to about half of what it originally was.  I suspect that the oil in your airbox is partially the result of the blowby caused by sticky rings.

Running it as hard as possible has seemed to help loosen things up on my bike.  Johnny is absolutely correct when he says that you need to get out and get some yeehaa to get and keep these machines running at top performance.  Carbon buildup in the cylinder and deposits on valve seats also respond well to hard running.  Running at 5-6000rpm is actually good for these engines.

[Filmcamera]

I agree that running at 5,000 - 6,000 is good for the engine and that these bikes need to be ridden often and hard to work at their best.

My only word of warning would be to do that high rev running in 3rd gear and above.  One other member and myself have both recently busted second gear  running at 6,000 plus.

[Ruben92]

Thanks for replying guys.


Thats also my experience. The more i trying to ref the * out of it, the more it runs better.
There are also coming explosions out of the engine, sometimes multiple small ones, sometimes one big bang.


I will use this as my main motorcycle now and i will let you guys know the progression!

[The Mighty Gryphon]

They will backfire if you don't close the throttle fully when engine braking.  I am still trying to break the habit of running a little bit of throttle.  The bangs remind me to shut it completely.

[Ruben92]

Update;


In the meantime the cardan gear was wrecked, so i replaced the thing.


Also i painted the motorcycle including the exhaust and exhaustpipes.
Yesterday a friend said; " Why did you only painted two instead all four"..
Cause of the heat the paint let loose. Sprayed some water on the pipes..


Only two pipes were hot.


Gonna check the sparkplugs again and i'll let you guys know!
Probably a faulty ignition coil?

[Ruben92]

Connected the ignition coil in the wrong order..
Huge power increase, but starts to leak oil out of the exhaust, probably needs some miles to flush the cilinder out.


Also uses less fuel now!


Thanks for everything!


Great forum  :2thumbup:

[smith913]

can you post a picture of your coil hookup? i am having a similar issue and am curious if it is the same issue

[Ruben92]

Im not able to take a picture at the moment, this is the way i hooked it up;


Front Coil; Blue/Black.       
Rear Coil; Red/Black


Both need a ground cable (i attached these next to the screwholes)
Also they both need the Green/Yellow cable, i put these on the slipons closest to the motor (backside of the coil)   


Hope this helps you!

[Laitch]

can you post a picture of your coil hookup? i am having a similar issue and am curious if it is the same issue

Here is a schematic for an early K100 like yours. See if the wire colors correspond to your set. Be sure the plug wire connections are paired correctly.

K100 coil layout from Vogel's K100 troubleshooting guide in the Motobrick.com Repair Guidance Master List.png (20.29 kB . 292x265 - viewed 1627 times)

 This schematic shows the plug wire pairings.

K100 coil layout from BMW workshop manual.png (104.73 kB . 330x271 - viewed 1763 times)