Throttle Position Switch Problem Solving

By Mogens Petersen
November 2001

I have inspired one problem with my '83 K100 with an EML GT200 sidecar.

On a journey the engine was suddenly cutting in and out periodically like dirt in the fuel.

After trying changing the spark plugs and the HT leads without any result, I tried to remove the plug to the butterfly switch----and suddenly all problems where gone!!!

When I got home I carefully broke the switch a part and it showed out that it was full of water.

After drying out the house and cleaning the switch contacts (in fact the butterfly switch consist of only one microswitch for indication of closed throttle and one larger switch for full throttle) I rebuild the butterfly switch and sealed it with silicone glue, put on the plug again and it has been OK ever since.

The problem seems to have been that the water had made a shortcut so the computer was thinking that I have closed the throttle ore was driving with more than full throttle and it therefore made a cut-off to avoid over driving the engine.

But the strange thing is that the bike is running perfectly well without the butterfly switch connected?

Thank you for a very good "page"

best regards

Mogens Fleron Petersen