Topic: Question about CB550 F engine trouble after 15 min

[2mnyshp]

Hi there

First off I have to confess that I'm a total noob when it comes to engines and mechanics in general .I recently bought an original 1977 CB550 F from a bike dealer because I just love the look and the feel of old bikes and I want to learn more about engines and mechanics . The engine of the bike has been revised and overall the bike is in pristine optical condition. Luckily it came with a three months warranty as it turns out...

From day one I'm (almost) only experiencing trouble with my CB.

Here my problems:

It is almost impossible to get the bike rolling softly; I turn the throttle slightly and the engine doesn't seem to pick up right away. I turn some more and all of a sudden the RPM go up to around 2500. It's virtually impossible to drive "normally" at lower speeds because I can't operate the throttle properly in the lower RPMs.

My other problem is that the motor stops idling correctly when the engine works at normal operating temperature (it works fine when the engine isn't hot nor cold). The bike always seems like it's about to die. Now in combination with my throttle problem the engine DOES usually die except when I really crank the throttle which results - as mentioned before - in a sudden and uncomfortable rise of the RPMs. This can’t be healthy for the clutch and It’s extremely annoying in stop and go situations. I also tried to set the carburetor screw so the engine does get more fuel while idling but the bikes just dies no matter what direction I turn.

I also wanted to know if it's normal for an old bike like that to "sweat" oil out of the engine block which is visible at the bottom of the radiator.

Has anyone experienced anything like that before or knows where there might be a problem?

Cheers!

[strynboen]

this engines lives from 4000 rpm up to 8500..all under 2500 are not give any power..you must have somone who drives japs bike learning you the tricks

radiator? cb 550 are aircooled..have not a oil kooler as stock

[LesterPiglet]

First you must get the engine to normal operating temperature then adjust the idle screw, big knurled brass one, (not air screws) to get a satisfactory idle speed.
Air cooled bikes don't have radiators.
No it shouldn't "sweat" oil.
Does the bike have the standard airbox?
Sounds like it needs a 3000mi tuneup and a carb sync.

[rb550four]

Could the radiator actually be the oil filter in this case?
Are  you running an oil cooler ?

[2mnyshp]

Sorry guys, I didn't mean radiotor. I was just talking about the outside of the engine that looks like a heat sink 

I tried the idling screw. The bike dies instantly no matter which side i turn.

cheers

[TwoTired]

Cooling fins ARE heat radiators fellas.

I'm thinking there is a language translation facet going on here.

But, if the shop gave a 3 month warranty, take it back to them.

But, get yourself a shop manual (Honda's is best, imo), because after the warranty period, you're going to have to work it yourself if economics are any concern.

My guess at the moment, is that the carbs need cleaning and adjusting, after the 3000 mile tune up check list is completed.

You can check to see if it is running on all cylinders by checking head pipe heat.  Cool or cold ones indicate cylinders aren't firing.  Dead cylinders will certainly make the bike drive poorly with low power, and remove most of the low end torque.