I was out driving my 87 Paso when I by mistake turned off the engine with the switch on the right handlebar. I corrected my mistake, but the Paso wouldn`t forgive me.
The engine started to feel and sound like it was only running on one cylinder. When I accelerated the engine felt and sounded normal, but when i tried to slow down it came back.

Is it the carburetor or some electric fault? I can clean the carburetor, but can someone help me with the electrics? How do i check it?

/Mats

probably both. Check the FAQs for the "wiring upgrade".
If that is done and the carb is well synchronized the bike should run fine again.

G.

First I would try just cleaning the spark plugs.

The kill switch is likely very dirty and/or corroded inside. I believe that switch was the cause of weak ignition and plug fouling on my bike for a time, until I dissected the switch. Cleaning it would be a good idea, but even moreso, do the wiring upgrades.

right, I skipped some steps. First be sure that all electrical contacts are clean before going for the wiring upgrade

I have changed the sparkplugs and the fuelfilter without any luck. The engine still acts like before.

/Mats

what are the conditions of old spark plugs? Are both light grey or one is darker?
In this case,maibe one ignition line has gone...
If you are quite skilled in mechanical handwork you can try to solve yourself the trouble, otherwise, go looking for a good dealer!

IGNITION DEBUGGING...

start the engine and pull the ORANGE WIRE off one coil and listern to the engine: if it falls down or dies the cylinder is working.
Repeat with the other one: If both the cylinders work good you might have to search somewhere else your trouble.

If one cylinder does not work good, try to excange the ignition boxes (engine off!) and repeat the operation.
If the cylinder not working is still the same, both ignition boxes run good.

try to excange the low voltage wires on the coils (maybe brown and green? I'm not sure about the color, anyway the other "non-orange" wires on the coils) and excange the hi-voltage wires to the spark plugs too.
This is to excange the coils without remove them. If the trouble don't change, this might not be an ignition bug.

WEBER IDLE CARB DEBUGGING

Remove all fairings and fuel tank, and arrange a fuel supply
Look for the idle jets in both sides of the carburateur
they look like a bronze screw just over the main axle. Start the engine.
Unscrew one of them just 1/2 turn and listern to the engine... If it runs higher, you found your bug: grain of dust in the jet, remove it and spray air in the inner duct.

This might be the right chance to have a look to the carb setup

Have a nice work, and

Thank you all for interest in my problem.
The carb is lying on my workbench and waiting for a good clean. If the problem remains I will go on with checking the electrics.
It`s a good thing that I have my summer vacation so I can find the time to try all of your excellent suggestions

I sure hope I will be able to help you sometime.

/Mats

So it's the Weber on there??

Check the FAQ as there might be some tuning info that can help you there. Also, try fitting a fuel pressure regulator as well. There was a recent thread on this.

After cleaning the carb the bikes runs just fine. Just to be sure i cleaned most of the electrics too.

When it´s time to stop driving for the season (hopefully november) I will upgrade the wiring and fit a pressure regulator.

/Mats

I had the same problem like you two summers ago and the result was a burned coil. Check your spark plugs, they have to do a good spark. If one of them not work you can to change the coil wires between (I'm sorry my english is very bad). You connect the wires of the coil nº 1 to the coil nº 2, and the wires of the coil nº2 to the coil nº1. Now, do the spark what didn't work before runs or no? If it works now maybe the problem is in the coil.