Topic: CB550F suddenly and randomly looses spark.

[JimmyPage1969]

Hi there.
For two years now ive got a problem with my CB550F. It has a Kokusan electronic ignition. Its randomly looses spark only when i,m riding it. Its starts right up and then after couple of miles or couple of days or even once in a.month it diem for couple of seconds then fires right up and everything its great. I checked it with spare spark plug than it looses spark on all 4 cylinders at that moment. All of.electrical equipment works consistently then. Sometimes it looses spark for half of a second somwtimes for 5,15,30  seconds. I checked the fuel, tank, line, carbs, battery, charging, wiring spark plugs etc. And last time when i checked and clean the wiring it Was riding spotless about a month. But after a monthe problem came back. One thing i didn't checked is kill switch.
Did any of you had same issue or know what it can be? Ive read that Kokusan ignitions are very reliable and it shouldnt be cause of this issue.

[denward17]

Welcome to the forum JimmyPage.....

About all I got is to check for a pinched wire from ignition system to coils.

Good Luck....

[bryanj]

There are a few possible places you could have an iffy connection including ignition switch and kill switch

[JimmyPage1969]

Hi denward . I found one. Yellow cable - probably sygnał to coils. Fixed it and it Was fine for one month but problem came back.

[HondaMan]

Expanding on Denward's approach: look at all of the little bullet connectors involved with the coils and ignition. The female sides (sockets) can become spread open or cracked, which causes troubles mostly when the whole bike is hot. They are then loose, so it is intermittent and doesn't show up when cold. Wiggling wiring then can also 'fix' it, for a while. The bikes came with 3.5mm bullet connectors: many aftermarket electronics come with 3mm connections, which can cause troubles that are intermittent due to loose connections.

Outside of that: heat will make marginal electronics quit working until it cools off again. The only answer for that is to change the electronic parts.

[rotortiller]

With antiques expect everything and anything with electrical contacts/connections in the ignition circuit as suspect feeding the coils. Kill switch, coil bullet plugs, points harness plugs near the brake switch, connectors in the headlight bucket etc.  The biggest mistake I make is going over areas I have already repaired and wasting time again lol. The boys are correct on the coil connectors not being secure enough, bought that T-Shrit already lol. Even high tension wires, ignition points, and caps may short out or insulate the electrical path for a partial loss. Poorly aged bikes of this vintage often have garbage electrical systems. They can be like a fit, well-groomed 60 year old  jogger with a morning boner or be like a fat, overweight, smoking, panting 60 year old toothless-wonder trying to chew Viagra. There is still hope, but only with skill and effort, things can still be made better, upgraded, or repaired some before reaching the bone yard. 

[Deltarider]

When 'it looses spark on all 4 cylinders' simultaneously, the suspects are the key IGN switch and the PLUS and MINUS connections of your Kokusan. Remember, it was you who has connected them. Check those first and everything else your hands have touched. As for widening female connectors, pay special attention to the Y-connector Bk/W wire where the PLUS wires sit that feed the coils. That Y-connector widens sometimes resulting in poor contact and intermittent loosing power.
Me personally, I don't like the Kokusan design and its predecessor (Accent Zündung). Do its male connectors exactly match the corresponding female Honda connectors in size?