Author Topic: Gas Leak Problem (Read 2965 times)

ozee · « **on:** March 31, 2010, 05:30:08 PM »

Hi-

I changed my oil today, and was riding around for awhile with no problems. I parked in my driveway and when I came home to start my bike up I started leaking gas (not oil) everywhere : ( As soon as I turn my petcock from the off to the on position gas starts streaming out of the drain tube coming out of my second carb. Any ideas of what is causing this or how to fix? Thanks for your help.

-Owen

ozee · « **Reply #1 on:** March 31, 2010, 05:33:20 PM »

Oh yeah... 1978 Cb 550k

Markcb750 · « **Reply #2 on:** March 31, 2010, 05:35:18 PM »

Stuck float, Fairly common problem on the SOHC machine.

Not hard to fix,I popped mine apart on the side of the road with a pocket knife a year and a half ago, 5 min later headed home.

Tom in Newcastle......Ontario · « **Reply #3 on:** March 31, 2010, 05:36:15 PM »

Float valve might have a chunk of crap between the valve and seat............try tapping the float bowl briskly with a screw driver

ozee · « **Reply #4 on:** March 31, 2010, 05:38:26 PM »

Thanks for your prompt help, but I am a total newb. where is this float valve that I should tap and how do I fix with a pocket knife?

Markcb750 · « **Reply #5 on:** March 31, 2010, 05:41:35 PM »

Quote from: ozee on March 31, 2010, 05:38:26 PM

Thanks for your prompt help, but I am a total newb. where is this float valve that I should tap and how do I fix with a pocket knife?

Go to the website you will find links to manuals, the Honda carburetor manual is there. It has pictures and a lot of information which will make what the members post much more helpful

Markcb750 · « **Reply #6 on:** March 31, 2010, 05:50:23 PM »

Here is a link to the Honda carburetor manual

http://www.sohc4.net/?q=node/65

ozee · « **Reply #7 on:** March 31, 2010, 05:58:47 PM »

Thank you very much.

Frostyboy · « **Reply #8 on:** March 31, 2010, 05:59:19 PM »

This might be worth a try before pulling the bowl off.
If it is something stuck on the float needle, turn the petcock off & drain the bowl on the carb that's leaking.
Then, when the float is at it's lowest position turn the fuel on again. You might just be lucky enough to flush the grit off the needle.
You will have to be lucky though, the gauze screen on the petcock shouldn't have let that big enough bit through in the first place.

OldSchool_IsCool · « **Reply #9 on:** March 31, 2010, 06:00:59 PM »

Tap the bowl with a screwdriver handle. 7 times out of 10, bowl tapping will fix it.

The float and valve are inside the bowl. If bowl tapping doesn't fix it, take the troublesome bowl off to get at the valve. Take care to make sure you reinstall the parts the way they came out. Getting the float back in upside down is a common mistake. In the 78 550 carb, I believe the flat side of the float should be nearest the carb body.

Edit: What Frosty said.

ozee · « **Reply #10 on:** March 31, 2010, 06:10:16 PM »

Thanks for all the help. I will tap the bowl again and see if that works. I really hope i get lucky with this because even though i looked at the float bowl system in the carb manual it doesn't really make sense to me and am very reluctant to take it apart... Is it just that one screw that you take off- the float bowl drain plug?

OldSchool_IsCool · « **Reply #11 on:** March 31, 2010, 06:17:41 PM »

To remove the bowl, there should be three screws that join the float bowl to the carb body.

The drain screw only needs a few turns counter clockwise to drain the bowl, it doesn't have to come out.

If you need an example of a float/needle valve setup, pop the top off you toilet tank and there ya have an example in extra large!

Frostyboy · « **Reply #12 on:** March 31, 2010, 06:18:09 PM »

Yep, the large brass one with the straight slot.
Collect the fuel in a piece of rag or maybe a container if you can find one to fit under the bowl.

ozee · « **Reply #13 on:** March 31, 2010, 06:24:55 PM »

you guys are awesome. I will keep you posted as to the status of my progress... THANKS!

ozee · « **Reply #14 on:** April 01, 2010, 03:03:36 PM »

Ok. I hit the float bowl with a screwdriver and the leak stopped. My friends have told me this is not a permanent fix. It has been recommended to me that I rebuild the carbs. I am going on a long road-trip with my bike (minnesota to colorado) this summer and I am wondering if this is necessary/ advisable. Thanks for your help.

750goes · « **Reply #15 on:** April 01, 2010, 03:11:43 PM »

If it ain't broke, don't fix it....

If it has stopped leaking, and the bike is running fine, then leave it alone and ride it..

Markcb750 · « **Reply #16 on:** April 01, 2010, 03:13:44 PM »

A good cleaning should be done, there are ports for low speed operation and for ventilating the float area that can plug from the varnish evaperating gas leaves behind.

Lots of threads here covering the topic.

Took me several attempts to find all the ports and poke them thoroughly. I found spraying carb cleaner into every orifice and looking for where it came out was helpful.

kits are about 25 a carb, but are often not needed.

Frostyboy · « **Reply #17 on:** April 01, 2010, 05:58:26 PM »

Quote from: 750goes on April 01, 2010, 03:11:43 PM

If it ain't broke, don't fix it....

+1.
No doubt in time you will be tearing those carbs down, however I'd be leaving it until some more serious or persistent symptoms develop.
Enjoy the ride while it's running sweet.

btw, us Owens have to stick together, there's not many of us.

ozee · « **Reply #18 on:** April 01, 2010, 06:46:29 PM »

Agreed frostyboy

an owen's an owen in my book.

eurban · « **Reply #19 on:** April 02, 2010, 05:29:34 AM »

I would suggest that you listen to your friends who are suggesting long term solutions for maintaining your 30+ year old bike. If you are serious about taking your 78 on a long road trip this summer then its probably a good time now to start learning how to work on and maintain the bike, and not just specifically the carbs either. Do you know the service history of the bike and that all systems are up to snuff? You are a very lucky man if you can answer "yes". If not then consider going over the entire machine before you venture far from home! Heck, post a thread saying "I'm going to take my 550 on a road trip this summer. What should I do in preparation?" Explain the service history of the bike, its apparent condition and your tool ownership status, skill set / abilities. Put it in the project section with a few pictures and start a valuable learning experience . . .

Markcb750 · « **Reply #20 on:** April 02, 2010, 06:31:35 AM »

Quote from: eurban on April 02, 2010, 05:29:34 AM

I would suggest that you listen to your friends who are suggesting long term solutions for maintaining your 30+ year old bike. If you are serious about taking your 78 on a long road trip this summer then its probably a good time now to start learning how to work on and maintain the bike, and not just specifically the carbs either. Do you know the service history of the bike and that all systems are up to snuff? You are a very lucky man if you can answer "yes". If not then consider going over the entire machine before you venture far from home! Heck, post a thread saying "I'm going to take my 550 on a road trip this summer. What should I do in preparation?" Explain the service history of the bike, its apparent condition and your tool ownership status, skill set / abilities. Put it in the project section with a few pictures and start a valuable learning experience . . .

what he said...

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Author Topic: Gas Leak Problem (Read 2965 times)

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