Topic: Cb550 intermittent cyclinder firing

[Aws161]

I recently purchased a 1975 honda cb550 four. I have cleaned the carbs, checked coils wires and plugs, and fuel flow. It is firing intermittently on cylinder four and backfires. There is oil coming out of the right exhaust. When the bike is running the right exhaust is significantly cooler that exhaust from cylinder 1 and 2. I have read many posts on this forums page and feel a top end tear down is probably in my future. I have not checked valve seals or compression yet, however i did do a finger compression check and both cylinder one (good running cylinder) and cylinder 4 (bad cylinder) and they both blew off my finger and seemed to show simular compression.  I have been told oil rings may be bad or valve seals. Any suggestions or ideas for what may be my issue? Thanks for your help.

[Gordon]

Many times people have confused soot-blackened water or unburnt gas dripping out of the exhaust to be oil.  What does the spark plug look like?  Have you changed the spark plugs and checked to see if you're even getting a spark on #4?  Have you done a full tune-up?

[Spanner 1]

When ya took out #4 plug to test compression, what color/wet/dry/black/oily was the plug ?

[Aws161]

Plug was fowled as hell. Replaced the plugs and yes i did check to make sure i was getting spark.
To reply to the second commentor the plug was black and wet

[Spanner 1]

Swap #1 and #4 plug cap and see does #4 fire ( with a new or proven good plug ) ... while your doin' that , look into the end of #4 plug wire. Can you see wire strands ?. Cut it back 1/4 in. and screw # 1 cap on there, but first clean out any crap left in the screw end of the plug cap ( the end the wire screws into )... try that.

[Aws161]

I ordered new caps and wires. Not in yet. I will try that asap. Thanks!

[Aws161]

I just remembered in all the experimental #^}% that i did to try to get in running right two weeks ago, i did swap 1 and 4 caps and wires. Soo thats unfortunatly not it. Ideasss?

[Aws161]

Another forgotten piece of information you should all know is that i replaces the jet in carb 4 because the PO had bored out. And that was after i swapped caps and wires on 1 and 4

[Gordon]

Another forgotten piece of information you should all know is that i replaces the jet in carb 4 because the PO had bored out. And that was after i swapped caps and wires on 1 and 4

How did you replace the plug wires?  Do you have aftermarket coils or did you splice in new wires to the stock coils? 

[Aws161]

I didnt replace wires and caps yet. I just took cap and wire 1 and swapped it with cap and wire 4