'74 CB550 gives me a headache.

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I'm having some troubles with my '74 CB550. Cylinders one and two (the two on the left if sitting on the bike) seem to be running normal, while cylinders three and four (right two) are not. After a period of idling, one and two will be hot, while cylinders three and four are cold. So cold that it is possible to actually grab and hold onto the head pipes. They are cold or barely warm to the touch. I cannot seem to pinpoint the cause of this. All cylinders have spark and all of the carbs are adjusted the same. Anyone have a clue what could cause this?

-- Tim Connelroy (mrtool45@hotmail.com), September 21, 2002


Tim there appears to be a problem with the fuel supply to the right side of your engine. What is the history of this problem? Have you had the bike sitting for an extended period on the side stand? If so, if the float needle valves are leaking slightly the fuel will drain from the right side carburators and the cylinders 3 and 4 will not fire until the bike has been returned to an upright position and the the right side carb fuel bowls have had a chance to refill. If the the right side float needle valves are stuck they may be freed by tapping the float bowls with a heavy object (hammer). If that is not the case give me more history and I will try to help you solve the problem.


-- Junkman Frankenbiker (everett@on.aibn.com), September 21, 2002.

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