Topic: 78 CB550 Misfiring?

[exponent]

Installed new condensers (again) and the bike ran fine but now somethings up. It will switch from running normally to feeling like its misfiring, it will buck instead of accelerating smoothly. It will rev when not in gear just fine however. Any info is appreciated

[BRG-BIRD]

Have done any other work very recently? Can you give more detail like if it acts up at certain rpms?

[Keith]

Condenser screws tight? What shape are the points in? A bad condenser can fry a set of points. Point gap and timing set?

[DaveBarbier]

What brand condensers? If they are aftermarket trash them and buy an OEM set. You want either TEK or ND (nippon denso). It is known here that Daichii, a popular aftermarket maker, makes crap condensers. Their logo is a three pointed flower.

Why did you replace the condensers the first time?

[dave500]

have a look at the plug caps,they might be old and gone too high resistance?

[Deltarider]

Check the spark does not jump (and so leak) between the HTleads or plugcaps and the engine. Best seen in the dark. Are plugcaps making good contact with the plugs?
Any arcing at the breakerpoints?
A bit of sparking is normal like shown in the vid at breakerpoint (2+3), the arcing at (1+4) however indicates a faulty condensor.

Another cause could be that after you fitted breakerpoints and/or condensers, one of the forked terminals at the back of the breakerpoints is too close to the plate and so intermittently makes contact to ground. The 2+3 breakerpoints is more prone to this, because it's more in the vicinity of plate and crosshead screw than the 1+4 breakerpoints. Make sure these forked terminals do not touch the plate!