Topic: Hello from Oregon

[Dmurphy6930]

Hello everyone, My name is Darren. I have just acquired a 1971 CB500. This is officially, my first motorcycle and couldn't be more excited. It does have some problems and Im hoping I can find help here to get it road worthy.

The main problem is when its running, it will only run for about 15 minutes before it peters out. Its not happy when engaging the clutch and trying to take off, and forgot about trying to take on a hill. Eventually, it gets to a point when it runs better with the choke engaged. Also, when it runs, it absolutely reeks of gas.

So, the problems I have found:
Slight smell of gas in the oil.
Plugs are REALLY black (but still have spark)
Bogs and dies after running for a while.
Gas cap is rusty and gasket is in bad shape.
Kickstart doesn't always seem to engage.

What Ive done so far:
-Replaced the battery
-Removed the carbs and checked bottom parts (everything seems to be fine, no varnish, no rust, nothing seems stuck, very minimal buildup on the floats.)
-removed the air box.
-checked the points and advanced the timing a hair.

What I plan to do next month (after payday):
-order a rebuild kit for the carbs
-replace the oil and filter
-order air pods
-replace all the fuel lines
-replace the gas cap
-get a timing light and try to dial in the timing. 

Is there anything Im missing or any other thoughts? I have no idea how to tune the jets so things could get interesting. Im looking forward to using this forum and hope I can eventually help others myself. Thank you.

[Kelly E]

I would skip the pods until you have the bike running correctly. Once it is then you put on the pods and try to get the jetting right for the new set up.

[MD]

Welcome from NE MN,

Even though you smell gas, I would guess you don't have adequate make up air entering the tank.  When it starts to bog down open the gas cap and see if it makes a difference.


-MD

[Gene]

Welcome! Regarding the possibility of gas in your oil - I would change the oil before I started it again.

Try what MD said re: the gas cap - it's possible the vent is plugged and that's your problem. Check the tank itself for interior rust and if it's bad, clean it now before that stuff gets into your carbs. 

Ignore the pods until the bike runs well as Kelly said.

And above all, have some fun.

this forum will help you get that bike back to being itself.

[Dmurphy6930]

Thanks for the feedback everyone, I wish I   could get it running with the old air box. Problem is, when I got the bike, the air box was damaged as well as the tubes connected to the carbs. Are air pods going to make that big a difference? I figured id just go up a jet size and go from there. I didn't see the point in ordering another air box if im planning on changing it out later. I will try the gas cap trick when i get the carbs back together.

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[RAFster122s]

Welcome.
Airbox is ideal for a stock motor, pods are a real pita to jet right and get running correctly. They ,pods, are more for racing applications and are a lot of work and expense with new plugs to get the plug chop readings for tuning the pods to run OK through the throttle range.  You would be better off tracking down the airbox parts needed.

You will be pulling the carbs a lot to tune and change jets etc on the carbs when trying to tune with pods.

Do not buy aftermarket gasket sets for your carbs,they aren't made very well and the brass parts are worthless for the sohc4 motors. Better to buy OEM Honda rebuild gasket set for the carbs and to clean your old brass parts if they are genuine Keihin parts.  Aftermarket carb boots have issues as well.

South Sound Honda of Olympia WA has some of if not the best prices on Honda parts and are very reasonable on shipping prices.

Lots of new owners mix up the choke being on or off, the bike should require choke to start and you will have to work the throttle during warm up to keep it running and the choke will be required less as it warms up.

Pull your spark plug caps and after removing them (unscrewing them from the wire ends) measure their resistance with a good multimeter. They should read 5k ohms if NGK caps. If they do not read close to this value, then they need replaced. Trim about 1/4" of wire off the end of the wire before screwing the caps back on the wire.

Perform the 3000 mile tuneup/mtce from the factory service manual if you have not already. Grease the swingarm and check it for excess play. Clean and lube your chain and sprockets and check the sprockets for wear.

When checking your points, ensure there is grease for the points cam felt. With  a timing light set your timing after adjusting the points. Check that the advance is working correctly with the timing light while it is hooked up. You may need to remove the points plate and then the points timing advancer mechanism to clean and lube it.

David

[Dmurphy6930]

Ill see what i can do with the airbox. The tubes from the airbox to the carbs were badly cracked. Ive been looking for oem replacements but those pieces seem to be hard to come by. Would South Sound have those? (Im not seeing them) Or would I be ok with an aftermarket set? Ive been looking at stuff from places like 4into1.com, dime city, and old bike barn, some oem but not a lot im noticing. Im trying save as many parts as i can but its difficult when you start looking at stuff and notice things missing or damaged.

 I appreciate the explanation with the air pods, ill put those on the back burner for now.


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[RAFster122s]

8   INSULATOR, CARBURETOR
16211-323-000   4   $11.58   $7.96

These are from intake manifold to carbs. Worth the investment since yours are probably 48 years old.


I am not finding the air box to carb boots in the fiche for the 71 cb500.
Are yours rubber or did they do the box in plastic and it did not have the rubber boots between the carbs and the air box plenum?
David

[Dmurphy6930]

That looks like what Im looking for, thank you! Yeah, the airbox and plume are plastic with insulators connecting the plume to the carbs.

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[RAFster122s]

I did not find the carb to air box plenum rubbers. 
Check other year 500 part fiche for those rubbers. Compare the initial plenum to the air box part numbers. It could be that they are identical all the way through cb550 '76 model production...
I don't know...

I have a '74 cb550.

[frenchy51]

Welcome neighbor from Nor-Cal. Lots of good advice here. That bike will be fun when you get it sorted.

[Dmurphy6930]

I hope so, ive got a shopping cart ready at 4into1, just waiting for payday to roll around. Im really hoping its something stupid simple. Ive been watching a lot of YouTube and found a lot of helpful videos and channels on this bike, especially Classic Octane, that guy is a wealth of knowledge. Im really hoping I can get this thing running and go for at least a couple of rides without an issue before winter.

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