Carb joint set leaking

[mpllis]

1985 Nighthawk 650,  appears that I have a gas leak on the carb joint set.  This is where the fuel line goes from the petcock down to the joint between carb 2 & 3.  I see that I can purchase a new joint set for about $40.  Anyone else ecperienced this or have knowledge of the joint?  I am going to pull the carbs.  I assume I need to seperate the carbs 2 and 3.  In the diagram it looks like there may be O-ringswhere the joint goes in,  is this correct are they just O-rings?  I am hoping that I can just get some at autozone.  Whatcha think?
The bike runs but is leaking some. 
Thanks all for your help!!

[coffee_brake]

When my '92 750 did this, I just went ahead and rebuilt the carbs. The complete (deluxe) rebuild kit will include every o-ring, new brass washers for the pilot screws, new float needles, and the o-rings for the fuel rail (the place that is leaking on yours).

If your carbs haven't had new float needles by now, they will soon. They may already be leaking, and it can cause the gasoline to go into the crankcase, which is very bad for the motor.

So yeah, you need the joint set and you might as well put in new float needles while you're in there. It's well worth the money since you have to take the carbs off the rack anyway.

If you can afford it, you might as well do the entire rebuild. But if the bike is running like a top exactly like it is, you might not want to even open up the carbs. You might want to just put in the fuel rail o-rings.

Whichever you choose, get yourself four small bowls for parts, one for each carb. or get an empty egg carton. Go very slowly with lots of light on a very clean surface. My carbs needed a hand-held impact (availalable at any tool store or auto parts store for maybe $12 or less) to get the biggest bolts loose. Trust me, use the impact before you strip those bolts. You'll find plenty of uses for that tool. Have a buddy hold the carbs still while you use it.
And I know you know you need the manual so you can account for every little part.....

[Munkey]

Should be just O-rings on the joint pipes. Bad part is you have to separate the carbs from the rail to replace them which blows the sync.

I got a whole box of assorted metric O-Rings from Harbor Freight for like $10.

[mpllis]

Thanks for the help.  A little history,  I was given the bike for free, she just wanted it out of her garage.  Has some paint chips broken turn signals and such.  But it does run.  Leaks gas but runs and only has 9800 miles.  My son and I pulled the carbs and cleaned them up. A problem it had is it wouldn't run without choke on.  It now runs fine.  I had thought the leak was the hose from petcock to middle joint.  I was wrong so pulling them again.  Not that bad a job except for getting the damn throttle cables back on.  I just finished a carb rebuild on a 85 Honda Magna VF700 which is a real bitch.  So these are easier.  ANy tricks on getting those cables back in?  So basically what I am saying is that we want to get the bike running first and then really dive in.  Oh yea , a question on replacing the o-rings on the middle joint.  I am hoping that I can seperate only the middle plastic joint,  is that possible?  I would prefer not to screw up the sync because the bike feels dead on.  If I have to resync I will.
Again thanks for the help and hope to be able to help some other people along the way.

[Munkey]

Usually the cables are long enough to put them on while holding the carbs beside the engine. Then put the carbs back on with the cables already attached.

[Laminar]

No need to replace the whole joint set, just the o-rings. Your best option is to get two carb rebuild kits, they'll have all of the o-rings you need for the joints on a complete rack of carbs.

Others have had luck with generic-sized o-rings, I haven't.

[spiritof86]

Take cable loose from the twist grip and then route it back up there when you get done.  Beats having to put them back on the carbs themselves.

[Laminar]

The throttle cables? They're not typically a problem...

[spiritof86]

That advice was for people who do have problems re-attaching the throttle cable(s) to the carbs.

[Laminar]

Hot dog fingers?

[spiritof86]

No, but they are a pain to put back on on the 700SC.

[Munkey]

No, but they are a pain to put back on on the 700SC.

Never had any issue doing mine. Hold the carbs beside the engine, put the cables on, then install carbs. It's only a pain if you install carbs first.

[mpllis]

We had taken the bracket that holds the cables off the carb and we were holding the carbs beside the bike when trying to get them back on.  We got it but it was difficult.
So where am I now, well we got it running and the leak for now has stopped on it's own.  Yes before spring we will be pulling the carbs and replacing the joint o rings.  I am very surprised how fast this bike is. 
Have a little problem still,  when you have the rpm's up and let off the throttle it is slow returning back down to idle, not crisp.  I am going to check and make sure there is no binding on the cables under the tank and at the carbs.  Still trying to get the air fuel mixture screws just right.  It is difficult to adjust those screws when the engine is hot because the engine is DAMN HOT.  So that is where I am right now. 
Again thanks to everyone for your help. 
Ride safe
Marc

[Laminar]

- Vacuum leaks
- Sticky throttle cables
- Carb sync