K75 Fueling problem - K-Bikes.com - Excellence in Motion
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post #1 of 3 (permalink) Old Dec 20th, 2011, 2:11 am Thread Starter
Join Date: Dec 2011
Location: Johannesburg, , South Africa
Posts: 1
Angry K75 Fueling problem

Hi Guys, great forum, hoping I'll still learn plenty on here.

I recently bought a K75C with about 77000km on the clock from a guy who did not really appear to know much about bikes. Needless to say, I soon learned after the purchase that the cooling fan was not functioning, but managed to sort that out with a second hand part. But now my main problem is this. The bike does not want to rev anything over 4500rpm which gives me a top speed currently of about 90km/h. I've checked the spark plugs aswell as the air filter which all seems fine, there is no gunk in the fuel tank, but the previous owner did mention that he removed the air screws in order to clean them trying to make the bike go better, but I don't know if this is what is causing the problem. Now my question is this, does the computer box keep any memory of possible over heating and this limits the bike in some way, will disconnecting the battery for a period of time possibly clear the fault codes or will I require more professional help? Unfortunately the K75 is referred to as an 'old' bike over here in South Africa, thus finding someone who actually know what they are doing is a bit tricky.

Hope one of you maybe came across this problem before or might have a solution for me.
JohanSwanepoel is offline  
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post #2 of 3 (permalink) Old Dec 20th, 2011, 2:34 pm
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Join Date: Jun 2009
Location: Petersburg, Va, USA
Posts: 129
What year?

What year bike is yours? It could make a difference in the details.

There's a switch on the end of the throttle shaft that cuts power to the injectors when you close the throttle all the way above a particular RPM (On K100s it's around 2K).

If that switch is malfunctioning or miss adjusted it could be part of your problem.

Check out this page:


and this page:


For all the dirt you'd need to know to sort out just about any problem with the FI.

With a new to you bike, you basically should go over everything to baseline it.

Take a quick look behind the air cleaner box just above the coils from the left side of the bike, there's a small rubber tube connecting the airbox with the crank case. If this thing is leaking your bike will run like crap. Same symptoms will happen if you run the bike without the oil filler cap on.


Tony G

'87 K100LT "Her Teutonic Majesty"
'79 XS750 "The Triple"
'72 A65T "The T-Bolt"
'68 B25 "The Blue Bike"
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post #3 of 3 (permalink) Old Dec 20th, 2011, 7:02 pm
Join Date: Aug 2007
Location: El Paso, TX, USA
Posts: 41
Which air screws did he remove?

You said the PO removed the air screws to clean them. Which ones did he remove, the unpainted ones or the painted ones? Did he synch the throttle bodies after he replaced them? Just asking...

Larry Johnson
El Paso TX
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