Topic: Could it be? Yes, another carb thread on the SOHC4 forum. (1973 CB500)

[JamesM]

I didn't want to stink up the "What did you do to your bike today" thread anymore with my carb problems, so I'm making this thread.

Bike is a 1973 CB500K2.

Back story: Carbs were pissing fuel out from between the bowl and carb base on number 3 and 4. So, I ordered four Keyster rebuild kits from Jerry's Cycle.

Took all four carbs off the rack and dipped them, cleaned them up good, put everything back together (set float height at 22mm) and get everything back on the bike. Turn the petcock on, no leaks.

Fire it up, carb #3 is dripping every 5 seconds or so between the bowl and carb. Take it for a ride up the road and back, now it's leaking out of 1, 2, and, 3 between the carb base and bowl.

Via another thread I've been told there's too much gas collecting in my bowls which I obviously agree with. Should I set my floats higher than what's recommended? Also, there is no gas coming out of the overflow tubes so I'm going to have to find out why.

Any help is appreciated, she's running great other than this problem, and is currently my only bike so I'm jonesing to get some seat time in.

Thanks guys.

[bollingball]

First off I'm not a 500 owner but I don't recall a 22mm measurement. Are you sure this is correct? Maybe you should post just how you made your adjustment for the floats maybe Dave or TT can help.
Ken

[JamesM]

I found this: http://www.motorcycleclassics.com/mc-how-to/honda-cb500-carburetor-rebuild.aspx and did as it says.

[haill]

The gaskets between the carb and bowls were they replaced at the same time?
does sound like your float height needs some readjusting.
22mm is the standard height you should make a gauge out of plastic which rest on the carb body and spans across both floats. the floats can get slightly twisted making your settings to low.
take your time, double check your work and enjoy riding your bike.
 

[JamesM]

Yep, new gaskets all around. I put them in with petroleum jelly and the slightest dab of super glue in the corners so they wouldn't move.

That plastic gauge is a great idea, thanks haill.

I'll be ripping the carbs back off this after noon after I get some seat time... on the lawn mower.

[CrankyOldGuy]

This reply is prefaced by saying I am not a CB500 owner.

If it's leaking between the bowl and carb I would have a look at how the gaskets fit.  I have read in other posts that sometimes the Keyster or other aftermarket gaskets don't fit perfectly.

Harry O.

[haill]

just a heads up when you take your carbs apart this afternoon the gas will have swelled your gaskets making them difficult to seat back into the carb bowls right away.
have found if you boil them in water for a short time then stick them in the freezer for 10 minutes they will shrink back down so you can assemble your carbs the same day.
they will also shrink down after being left in the open air over night.
small amount of grease in the bowls gasket/o-ring channel helps to keep them in place. Not sure about the super glue! you might want to omit that in case it's hampering the correct expansion of the o-ring causing the leak.
the bowls should hold gas regardless of how much gas is in them.
it would/should be coming out the overflow or leaking into your motors cylinders but not leaking around the bowls to carb connection. IE if your floats were severely out of whack or you had a stuck needle etc.
you might also want to check metal tubes in the float bowls they have been know to get hairline cracks that cause leaks, they can be solderd over.

[lucky]

If I had encountered that problem I would have ordered 4 BRAND NEW floats and seats and installed them and checked them End of story.


Cleaning the carbs and putting in those other parts did not help the overflowing carb float bowls.
I would have checked to see why the extra fuel was not coming out of the float bowl drain  tubes if the levels were that high.

[JamesM]

Where can I buy new floats for my bike lucky?

And the super glue did mess up my gaskets I think... so I went ahead and ordered four more.

Going to install them with Hondabond this time as a member on this site suggested unless there are negatives to that?