Motorcycle Repair: Honda CB 500, honda cb 500, honda cb 500 four

Question
Hi Bill-I recently picked up a 1973 Honda CB 500 Four. It has less than 12000 miles, but has been sitting for some time. It runs, but clearly not at peak performance. I guess I have a couple questions.

I'm getting gas leaking out of the overflow for one of the carburators when the motorcycle just sits. (Maybe float problem, I figure...) A friend suggested draining the carbs, pouring in some fuel injection cleaner, and then draining again to clean them out. Is that a good idea, or is there a better way to try cleaning them out without taking them apart completely? If I try this technique, how can I make sure the cleaner gets into all four carbs?

Is it a good idea to put the fuel injection cleaner in with a tank of gas?

For the same bike: It's a little tricky getting started in first gear. I have to give a lot of gas and really ease out the clutch. Would a clutch adjustment help here, and if so, is that probably a sign the clutch is too tight, too loose...?

Many thanks,
Dan

Answer
Dan, try the Yamaha brand carb cleaner product, use as directed. It is kinder to carb parts than FI cleaners. Depending on how bad they are, you still may have to pull them for a thorough cleaning. Just drain the carbs, refill with the cleaner/gas solution, let it sit and drain again from the bowl drain screws. There are a LOT of small O-rings inside these carbs, and they do deteriorate after 30 years.

Certainly make sure that the clutch adjustement is correct so you have about 1/8" free play at the lever. I imagine that the clutch plates got all stuck and rusted, so there are rough surfaces in there. Be sure to change the oil a few times in the first 500 miles to get all the crud out of the motor.

Once you get it firing on all 4 cylinders, timed correctly and carbureted, it should be okay. Put in some fresh plugs after you sort out the carbs and ignition timing. Watch for leaking head gaskets on that model at the outer ends.

You can do a top end on the engine with it still in the frame. Get a good shop manual from www.helminc.com or www.motorcyclememories.com or EBAY.

Bill Silver