k100 misfire judder

[shandybills]

My 1988 k100 has a misfire on tickover sounds like a clunk and the revs drop for a split second, also seen when balancing TB  the gauges drop like a missed beat, Initially had a dud coil replace with a second hand one all cylinders running but still have the misfire, When riding it seems a bit boggy or fluffy or holding back. Thinking it could be hall sensor or coolant temp sensor. Any help guys.

[Laitch]

How old is the fuel filter? Have you checked the tank fuel hose connections for tightness? Does the crankcase breather hose have splits in it?

[shandybills]

just took the hall sensor off and looks like someones done some soldering bodge in it the solder joints were not insulated so assuming this could be the problem

[Laitch]

 

[shandybills]

Changed plugs, leads, One coil changed as was only running on 3 now all 4 work. Changed the Hall pickup trigger sensor and not cured the problem, if i take a vacuum cap off i can see a flash down the hole when it misses a beat