Hi. I have recently bought a 1984 K100 RS. It ran perfectly on the test run but last night when I went for a ride it started to run really rough. It coughs and jerks. It gradually got worse. Today it barely runs. Just wondered if any of the members might have an idea what is wrong. I checked the plugs, they were very sooty but are all sparking ok. The previous owner had just completed a 300 mile trip with no problems.

hi bionic ,

sounds like you have a fuel delivery issue

there are lots of posts about old rubber , fuel pumps their connectors and fuel in the forum

lots of luck

Sounds like a fuel pump not delivering or a filter blocked. Try a filter first but don't go buying a new OEM pump but ask here first about pumps.
If you go to the portal you will find a thread marked "You have just bought a K100 So what now"
It will give you a good overview of things that need to be done to get it up to scratch.
If you go to the introduction thread and say hi to the gang it also gives you access to heaps more info in the downloads section.
And don't believe anything a previous owner tells you.

The fuel air mixture, is regulated by the amount of air entering, but more important: The time the injector is open in milliseconds, if the fuel pressure at the entrance of the injectors is correct. So check if the fuel pressure regulator is working well ... recall that this depression is controlled by the air manifold admição, the tube may have air leakage, or the regulator to malfunction. I remember that he has to maintain 36PSI.

Also check the temp. sensor resistance at the connector to the FI ECU (pin 10).

Compare with the diagram at the troubleshooting guide, which you find in the portal.

If it does turn out to be the fuel pump then this guy is selling oem one's at a bargain of a price.... It is where I got my replacement one from

ebay fuel pump

that's the best price i have seen on a clone pump for a K

it is a superb fit, comes as the pump alone and works just like an oem one! I think the guy must have bought them in bulk some time back but they come very well packaged even with replacement terminal fittings and rubber boots for the cables!

Thanks for posting the link - only £5.00 more than the Peugeot pump I have fitted at the moment too

Hi Krambo,

From which Peugeot model did you get the pump?

Mike

The other question with the Pug pump is is it a perfect fit or need adaption? for £5 extra it could be worth the extra for a simple swap rather than needing to play around...

In reply to the previous posts - the replacement pump I used was for a Peugeot 205 GTi 1.6i 1987-88 - the one I purchased was brand new/boxed/old stock and is an exact match for our pump - it fits without any modification required. Like I said - it was an old stock but unused item and came in sealed packaging etc. It has worked without issues since I installed it - hope this helps

Thanks for that, worth bearing in mind.

I just bought a second hand one to replace an original that was seized up. All working o.k. so far, but good to know which alternative is suitable.

Mike