HONDA SERVICE BULLETINS:

At the moment I don't have my hands on the actual service bulletins, just this list of what they are. Note: "The Wrench" was a news bulletin published by Honda.

-POWER LOSS:

Some people have complained about a general lack of power, usually problems revving past 5500 rpm or so under load. I limited the options down to fuel delivery, air delivery, and timing. To make a long story short, it was air delivery - even with a new filter. The inlet cover that holds the filter in place was restricting the airflow! I discarded the cover and used washers to hold the filter in place. See picture below. Another idea mentioned to me was the gas cap vent becomming plugged, preventing adaquate fuel flow to the carbs at the higher rpm. Hopefully one of these ideas will work for you.

-CHARGING PROBLEMS:

These bikes all seem to have problems with charging at some point, so don't worry.
Actually, go ahead and worry, just don't be suprised.

Here is a general fault finding chart for motorcycle charging systems:		Electrex Fault Finder Chart (PDF)
And here is a CB650 color wiring diagram in case you're missing the manual:		CB650 Color Wiring Diagram (JPG)

The most common problems:

• Bad wiring between stator assembly and the regulator/rectifier.
• Bad rotors, windings short out. Heat breaks down the rotors insulator material.
• Regulator/Rectifier can go bad.
• Brushes inside stator cover can wear out. (I'd say the least likely of them all)

-ROTOR REMOVAL:

You will need a strap wrench to hold the rotor in place while removing it's center bolt. To actually remove the rotor, you will need a flywheel puller. Some people have said that you can use the rear axle shaft (18mm?) from the bike to thread into the rotor and do the same job. This is up for grabs, because the first time I tryed it I ruined the axle. (Fortunatly it was lent to me by the salvage/parts shop I bought the rotor from). The next time I did it, I used my own axle, but instead of tightening it all the way I threaded it in, and took a hammer to the backside of the bolt flange. This worked like a slide hammer or dent puller does, and it was incredibly easy. See picture below.

Poor charging was the first problem I encountered with the bike. If you're having you're own problems, just take a deep breath, because with any luck it's not nearly as bad as what I had to go through.....

• Previous owner said the rotor was replaced. (Might have been, or not. I don't know)
• Led me to assume the rotor was good. (Mistake)
• Stator tested out good, so I replaced Regulator/Rectifier, used from a junkyard
• Didn't work, took R/R back to junkyard and exchanged it for a different one.
• Still didn't work, so threw in the towel and took it to a shop.
• Shop said it was the R/R(!?), replaced it, and it worked for a month(!? - No idea why)
• Took it to shop #2, diagnosed problem as faulty rotor.
• Went to different store and ordered a remanufactured rotor.
• Worked, but in the end cost me at least three times as much as it should have.

What further complicated this situation was a messed up wiring problem. The original owner ripped off the headlight bucket and signals to install a fairing. The owner I bought it from had attempted to remove the fairing and "reconstruct" the wiring. It was a hack job beyond belief. Wires hanging everywhere (including grounds). Bought a original used harness and installed that.

-CARB VENT HOSES:

The vent tubes on the carburators rot and fall off. They are more or less impossible to replace without seperating the carbs. This is not a problem, you can either try to hang them in place or take them off. Some people have said that fuel poured out of the holes, this is an indication of a more serious problem as it is a vapor vent (probably bad floats). You can usually find a similar rubber "T" at a hardware store, or purchase the originals from Honda (for $33 each) if you really want to.

-HEAD GASKETS:

Very common, on Honda's single cam bikes in general. Usually oil will weep out the sides where the oil galleys are. SEE PIC BELOW. Also, don't "mirror polish" your gasket surface here or anywhere else on the motor. If you look closely, you will be able to see the machining marks on all the gasket flanges from original production.

-CAM CHAIN NOISE:

Another very common problem. Chains stretch, and the tensioner can wear out too, allowing the chain to fly all over the place. Sound has been mistaken for bottom end noise, make sure you periodically adjust the tension before making any assumptions. I really wouldn't worry about this thing breaking - and you'll never get rid of the noise completely. I replaced my chain and tensioner with OEM Honda parts, and it sounds exactly the same.