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Discussion Starter · #1 ·
Hi Guys,
I've been trying to find a post on this specifically but I cant find any post of people with this issue that isn't a somewhat simple fix of tapping on the carb or adjusting a float. Not that I think i'm the first person to have this issue but I cant seem to find any posts.

So, I finally got to the point in my now 2 year long project where I'm getting close to having it back together. The only issue is I cant seem to stop my left side carb from overflowing, I've tried a few sets of floats and needles, I've swapped the floats from side to side since the right side seems to be working fine but no matter what I do the left carb keeps overflowing all over my garage. I don't want to just replace them because these are already replacement carbs I spent about $200 on, and I cant find any of a similar quality for a reasonable price. I'm worried that it might be the fixed float bowl seal is damaged and not sealing to the needle. I'm not sure what to do about this as I don't know how to cut the seal back into shape, and not sure if I feel comfortable doing myself.

Its a '79 Custom, and the carbs are a bit later with the accelerator pump off of a '80 deluxe I think.
I also am using a non-vacuum pump petcock if that's important in anyway.

Thanks Guys,
Dan.
 

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'84 CX650E that is evolving into a GL500
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Welcome to the forum. Please add your bike's model and model year to your signature (see Forum Settings link in my signature) so that you don't have to remember to tell us every time and we don't have to keep asking when you forget.

And welcome to the world of antique vehicle ownership. Your bike has had 4 decades of Previous Owners who may or may not have done the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage. I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel because old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet. If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) start shopping for modern stainless braided ones (they last practically forever and double the life of the fluid).

Re carb overflowing:

It won't hurt to examine the o-ring on the drain screw but all it does is keep fuel from escaping around the screw when the screw is loosened.

The first thing to do is make sure the drain screw is done up. It does not need a lot of torque, just enough to lightly seat its conical tip in the conical seat.

If that doesn't fix it (we can hope), turn the petcock Off, put lots of rags and maybe something to catch the fuel you will spill under the carb, drop the float bowl with the carbs in place, then hold the float up with your hand so that the float valve is as seated as possible while turning the petcock to Run. If fuel comes out around the float valve needle that's where the problem is but if it doesn't and the float height is correct the problem is elsewhere.

- If the float valve leaks have a close look at both the needle and the seat. Have you cleaned the seat? If not, remove the float & needle (you will have the petcock Off again by now) and scrub out the seat with a q-tip dipped in carb cleaner or methyl hydrate to remove any traces of varnish. Are the needles you tried all Honda ones or are some of them possibly aftermarket? Some aftermarket carb kit sellers are notorious for including needles that are either poor quality or the wrong length...

- If the float valve is OK sit the float valve on the workbench on/in something to catch any spills put some fuel or alcohol (methyl hydrate) in the float bowl and see where the fuel is escaping from.
-- If it is leaking anywhere except the drain/overflow barb on the bottom of the carb you have found the problem. Replace the float bowl.
-- If it is coming out the drain/overflow barb on the bottom remove the drain screw, clean the screw and its seat (q-tip and more carb cleaner or methyl hydrate) for debris or surface damage.
---- If there is any damage to the tip of the screw or the seat replace them.
---- If the screw & seat are OK re-install the screw and tighten it until lightly seated and try again.
------ If it has stopped leaking you have fixed the problem.
------ If it still leaks examine the brass overflow tube with a magnifying glass. The cracks usually run lengthwise near the bottom. Some people have repaired the cracks with solder, others have replaced the tube (most hobby shops that cater to model builders stock small brass tube).

Let us know what you find.
 

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Discussion Starter · #4 ·
Thanks Guys, I will try testing the floats on the bike with the bowls off when I get a chance these coming weeks and I get back to you guys when I do.

In the mean time I figured I would let you guys know that I've gone through the engine and most of the mechanical bits since the engine had major problems thanks to the last mechanic to work on it somehow screwing up so badly that the bearings for the one way clutch spilled out and put a large dent in my stator and requiring a new crankcase as well. The carbs were untouched since I had got them but I did look through the seals on the float bowl and they were fine. currently I've tried both the float bowls from my older carbs and multiple drain valves, on top of filling the bowls when they were off the engine and not having any leaks. I believe my bowls, drain valves, and overflow tubes are all in working order since I've swapped them around and had no leaks on the right side carb when they were fitted there. I've tried the original needles and floats but they still leaks, and I have swapped the current set of floats and needles back and forth between both sides with the leak always on the left side.

I've gone through the process of rebuilding an antique car before and loved it :D, and its been a similar situation with the bike.

Thanks guys for the help, I'll let you know when I've figured out anything else.
 

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I just had a case of a fuel leak that I thought was a carb leak on my gl650. Pulled the tank and went to a temp fuel bottle. No leak. Replaced the original petcock on tank no leaks. must have been dripping along fuel line onto the carbs. Worth a look anyway.
 

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'84 CX650E that is evolving into a GL500
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If the float valve is sealing properly no more fuel should enter the bowl once it is full, even with a non-vacuum petcock that is left on all the time.

Dano, it sounds like you have eliminated the bowl, float and needle from the equation. The only thing left is the seat. Try cleaning it with a Q-tip and carb cleaner or methyl hydrate ans check the valve before you put the bowl back on. If it still leaks the next step is pulling the carbs and having a good look at the seat.
 

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Discussion Starter · #7 ·
Hi guys, I finally got to working on my carbs again and have some information.

First off I bought a new carb kit for these carbs because I found a large amount of what looked like a red sealant in the jet that leads to the long needle, and found that my right side carb was missing the air cut valve entirely, there was only a spring under the cap. Once I replaced all my jets, needles, seals, accelerator pump, air-cutoff, and most importantly my floats. Even with the new floats the leak continued so after some minor rage and confusion at this apparent failure I also found a crack running up from the base of my float bowl drain. I'm sure this wasn't the only thing that was wrong because I've swapped my other bowls from my old carb and it still leaked, but through all of my efforts I was finally able to get the leak to stop somehow.

Here's hoping that that solves this issue for good. Thanks for your help guys, This bike is always another surprise waiting to happen and any help is appreciated.
 
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1982 GL500i
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I always get/have a set of used spare carbs for any of my bikes. Older bikes often have been through untold abuse or neglect at the hands of someone else, and eventually end up in mine, lol! You would not believe some of the crazy, unbelievable screw-ups I have found in carbs over the years. It is rare that I ever even see a set of carbs in unmolested, factory form. -Graves-
 
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