Nipples under carbs leaking all over tranny

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joejohn
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Nipples under carbs leaking all over tranny

Postby joejohn » Sat Jul 28, 2012 9:25 pm

Hey all,

I'm new to the forum and am glad to see a site dedicated soley to my new bike. I'm predicting I'll be posting a lot on here in the coming months. I just picked up a '79 cb650 this morrning, she's ratty, but everything seems to be there. Anyways, the guy I picked it up from said it had been sitting for a couple of years. He put in a new battery, pulled the air box, and put in pods. He never got it running right.

Here is the problem, when I open up the fuel cut off, the nipples under each carb start leaking gas. After checking a manual I found online and the bag of spare parts he handed me, I found four black lines around 1/8 to 1/4 OD that should've run from those nipples to (?) something that's no longer there. Any way to stop the leaks so I can fire it up? I tried tightening the screws for the drain on each carb, but nothing happened. I managed to get her started on just starting fluid, she idled ruff, but I figured out that the wires from #3 and #4 were crossed.

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Volker_P
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Re: Nipples under carbs leaking all over tranny

Postby Volker_P » Sun Jul 29, 2012 5:28 am

Welcome here! :D

joejohn wrote: He put in a new battery, pulled the air box, and put in pods. He never got it running right.

No surprise here, pods on PD carbs ask for considerable rejetting. If you don't want to go back to the stock airbox, please refer to the 79 cb650 carb jetting question thread for some idea which jet size you may need.

Carb overflow is often dirt out of a rusted tank. Inspect and clean the tank first to avoid mutiple carb work. The filter screen in the petcock is too coarse. So if you don't get your tank perfectly clean, install a fine enough inline filter.
The hoses are just guided down to the rear of the engine at open ends so overflow won't hit the engine. Nothing you really need or what is required to stop the leak. The key for that is the needle valve inside the floater bowls.

The drain screws open a channel to the bottom of the floater bowls for draining them, but there is a second overflow channel to this nipple which is permenently open. So don't maltreat the poor drain screws trying to stop the leak. :wink:
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

joejohn
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Re: Nipples under carbs leaking all over tranny

Postby joejohn » Sun Jul 29, 2012 2:25 pm

Thanks Volker_P!

Unfortunately, the pile of parts he gave me with the bike did not include the original airbox. The drain screws are already a little chewed up, but nothing too serious. I guess the next step is to clean the tank, replace the inline filter, and re-jet the carbs.

Beyond that, after playing with the bike a little last night, I now suspect cylinders #2 & #3 aren't firing. I swapped the cables from #1 & #4, but still nothing (I'm not sure that would've worked anyways.) So next on the list is to pick up a thin wall 18mm socket to check the plugs, then figure out whether or not I'm dealing with a spark problem on #2 & #3 or a compression issue.

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Folsoml
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Re: Nipples under carbs leaking all over tranny

Postby Folsoml » Sun Jul 29, 2012 3:02 pm

Are you aware of how the cables are supposed to go from the coils to the plugs? It is a common mistake to assume that the two cables from the left coil go to the left two plugs and the right coil go to the right two. This is not correct. As you are sitting on the bike, the cables from the left coil go to plugs 1 and 4. The right coil cables go to 2 and 3.

I hope this helps.
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joejohn
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Re: Nipples under carbs leaking all over tranny

Postby joejohn » Sun Jul 29, 2012 3:26 pm

Yeah, the wiring order was the first thing I searched for on the forum when I felt the rough idle. After correcting that, I proceeded to remove each individual cable to check for changes in the idle. When I removed #1 or #4, the engine would die. #2 & #3 can be removed at the same time with no changes to the idle (still rough though). I tried running the wires from #1 & #4 to #2 & #3 just to see if I could get them to fire, but I got nothing. I'm not entirely sure that would have worked as a test on this bike anyways. I just want to eliminate the possibility of a spark issue before I move on to compression testing.

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Folsoml
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Re: Nipples under carbs leaking all over tranny

Postby Folsoml » Sun Jul 29, 2012 4:12 pm

If spark was the issue, switching 1 and 4 to 2 and 3 should have worked. Seems like something else is the problem.
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bolo79
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Re: Nipples under carbs leaking all over tranny

Postby bolo79 » Sun Jul 29, 2012 11:23 pm

Hey joejohn!
Have you checked whether you have a spark in the right coil?Cylinder 2 & 3 operate on it, so you might want to check this before you move the compression test.

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Volker_P
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Re: Nipples under carbs leaking all over tranny

Postby Volker_P » Mon Jul 30, 2012 6:07 am

I agree here. 2+3 are separated by the cam chain tunnel so no option for a blown head gasket here.

Folsoml wrote:If spark was the issue, switching 1 and 4 to 2 and 3 should have worked. Seems like something else is the problem.

No. May cause a loud bang in the exhaust but will not make cylinders run as timing is shifted by 180°.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

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Folsoml
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Re: Nipples under carbs leaking all over tranny

Postby Folsoml » Mon Jul 30, 2012 4:34 pm

Volker_P wrote:
Folsoml wrote:If spark was the issue, switching 1 and 4 to 2 and 3 should have worked. Seems like something else is the problem.

No. May cause a loud bang in the exhaust but will not make cylinders run as timing is shifted by 180°.


Oops. :oops:
Have a problem with your CB650? Have a technical question? Click here!


My Current Bikes: 2005 HD FLHTCUI Electra Glide Ultra Classic, 2007 Yamaha Vino,

joejohn
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Re: Nipples under carbs leaking all over tranny

Postby joejohn » Mon Jul 30, 2012 5:27 pm

Thanks again Volker_P. I wasn't sure if the timing would allow that to work.

When I pulled the cables from #2 & #3 I did get shocked, something that doesn't happen when I mess with #1 & #4. I think something might be wrong with the right coil. Since I know that my left coil is good, is there any way to reverse the wiring so my left coil works in the place of my right coil and vice versa?

If I could do that then I'd know for sure. I just don't want to fry something trying something I don't even know will work.

joejohn
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Re: Nipples under carbs leaking all over tranny

Postby joejohn » Mon Jul 30, 2012 5:46 pm

Ok, after reviewing a schematic I found here: http://www.jasonkent.ca/manuals/79%20CB650%20Service%20017.pdf
I think I may just be able to switch two wires (yellow/blue) and reverse the order of my coils.

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Volker_P
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Re: Nipples under carbs leaking all over tranny

Postby Volker_P » Tue Jul 31, 2012 1:15 am

Yes, if you swap the primary blue-yellow connections of the coils, you just can try the left (1+4) coil for 2+3 and vice versa if plug cable lengths should allow that, too. Most straightforward way.

Alternatively you could also swap pulse generator cables or reassemble the advancer 180° off.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

joejohn
Posts: 27
Joined: Sat Jul 28, 2012 8:38 pm

Re: Nipples under carbs leaking all over tranny

Postby joejohn » Tue Jul 31, 2012 1:47 am

It was just easier to swap out the left and right coils with each other. However, the battery died before I could get her started again. I hooked it up to my trickle charger, so I'll test it tomorrow morning.

cgswss10
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Re: Nipples under carbs leaking all over tranny

Postby cgswss10 » Tue Jul 31, 2012 4:11 am

When I pulled the cables from #2 & #3 I did get shocked, something that doesn't happen when I mess with #1 & #4.


If you are getting shocks from the wires to 2&3, you have a good coil. Shocks from these wires would tend to indicate that the wires are bad. It is common with 30 year old spark plug wires that they "leak spark" This would cause a short to the head when trying to run the bike. In effect, the spark is running from the wire to the head insted of jumping the gap on the plug.

I don't think you are going to avoid the fun job of removing the carbs and cleaning them. You will surely need float bowl gaskets (unless you want to use "gasket maker" in a tube (not something I recommend!) I have often seen float bowl gaskets offered with new needles on e-bay. You might want to pick these up (Its much less costly then getting full rebuild kits for each carb)

I hope you have an e-bay account and a paypal account. This is going to be your #1 source of parts!

joejohn
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Re: Nipples under carbs leaking all over tranny

Postby joejohn » Tue Jul 31, 2012 3:27 pm

Yeah, I'm not avoiding cleaning and re-jetting the carbs, just trying to diagnose any problems before I start stripping parts. Unfortunately, I can't keep the bike running for more than 30 seconds.

After swapping the left and right coils, it seems like #1 & #2 are working and #3 & #4 are not. I think I have a combination of bad wires and at least one bad coil, but I can't be sure because I can't keep it running. I guess it doesn't really matter though, I'm going to have to replace some things on a 30+ year old bike if I want it to run reliably.

So I guess my next step is to clean the tank, clean/re-jet the carbs, clean all my electrical contacts, and install some new coils and cables. If that doesn't solve it, I guess I'll move on to compression testing, but at least I'll have fuel and spark solved.

I hope my Clymer manual gets here soon...


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