question about fuel tank petcock and path to carburetors

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juntjoo
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question about fuel tank petcock and path to carburetors

Postby juntjoo » Mon Feb 26, 2018 9:50 pm

does the path from the fuel tank petcock to the brass fuel tube over the carbs have to be slanted downwards to allow fuel to drop?

petcock to carburetors https://imgur.com/a/u2zvA

what I did to it was rebuild the petcock, and remove the vacuum operated one that no one likes, then connected a tube there but it's mostly horizontal and maybe a bit vertical before it curves downward onto the brass tube and Ive put a lot of fuel in the tank and confirmed it makes it to the bowl at the bottom of the petcock. So what could be blocking it's path beyond that bowl? Did that evil petpock I removed have a particular function that must be substituted somehow that I missed?
82" cb650 Nighthawk

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GeorgeSweety
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Re: question about fuel tank petcock and path to carburetors

Postby GeorgeSweety » Tue Feb 27, 2018 2:47 am

jj, I have just routed my Kawasaki fuel line practically the same way as yours as I needed to get an inline filter in there. I haven't had a problem with fuel getting to the carbs as yet.

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Volker_P
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Re: question about fuel tank petcock and path to carburetors

Postby Volker_P » Tue Feb 27, 2018 5:50 am

Have a look at the right side of this picture (and better ignore everything on the left :lol: )
The free hose end directly plugged to the (here missing) petcock.
This hose even made an upwards loop so the car fuel filter fitted in here.
Worked fine and so should yours.

The function of the "evil" part has to be substituted by you thinking of closing your petcock manually after a ride.
If you should have cold start issues, you may do that a few 100 meters before you park the bike so you get the floater bowls (close to) empty before the next start with fresh fuel from the tank. :wink:
Usually the floater valves are tight, too, but better not rely on them alone.

Image
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juntjoo
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Re: question about fuel tank petcock and path to carburetors

Postby juntjoo » Tue Feb 27, 2018 6:25 am

thanks guys. So if fuel isn't making down past my petcock bowl, then what could be the issue? As of now I've got about a gallon in the tank, can find fuel in the bowl if I unscrew it real quick, but I've spent all the fuel available to the carbs and can't get anymore. Now I've rebuilt this petcock a year ago about and recall verifying it's proper operation only with some water. One thing to point out is the valve is difficult to operate, like that gasket under the handle is newly fat and snug, which if it's not the problem, I don't mind either, but I'm just pointing that out. And that's all I can tell ya about it. Any ideas before I take it apart again?

Does the flow have to be SO free whereas mine to the bowl must too little to go beyond there? Could that round wafer gasket be too tight? I don't recall it's holes or overall dimensions being off visually at least. Again I recall verifying with water all positions worked, off, on and res.

thanks
82" cb650 Nighthawk

juntjoo
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Re: question about fuel tank petcock and path to carburetors

Postby juntjoo » Tue Feb 27, 2018 6:31 am

and I'm talking about the petcock bowl. that's as far as my fuel is going and not beyond right into my clear fuel line that I can see.
82" cb650 Nighthawk

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GeorgeSweety
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Re: question about fuel tank petcock and path to carburetors

Postby GeorgeSweety » Tue Feb 27, 2018 6:45 am

Well I'd guess that the problem would be in your petcock bowl if fuel isn't getting in to your fuel line. When you used water to test it did you make sure you got all of the water out? I believe the petcock bowl has a filter inside and if it was full of silt with water mixed in then fuel wouldn't get past.

juntjoo
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Re: question about fuel tank petcock and path to carburetors

Postby juntjoo » Tue Feb 27, 2018 7:30 am

okay, just found this morning fuel has made it past petcock down into carbs. but taking this long I hope it won't be a problem. we'll see. I'll report back
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GeorgeSweety
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Re: question about fuel tank petcock and path to carburetors

Postby GeorgeSweety » Tue Feb 27, 2018 7:40 am

jj, your fuel needs to flow freely, it should not slowly trickle through.

juntjoo
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Re: question about fuel tank petcock and path to carburetors

Postby juntjoo » Tue Feb 27, 2018 8:37 am

GeorgeSweety wrote:jj, your fuel needs to flow freely, it should not slowly trickle through.


k thanks. I'll keep an eye on it
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Volker_P
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Re: question about fuel tank petcock and path to carburetors

Postby Volker_P » Wed Feb 28, 2018 2:02 am

juntjoo wrote:Any ideas before I take it apart again?

Pull the hose from the petcock, put on another hose there, then release some fuel into a jar. This way you get an idea how much fuel could go into your carbs.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

juntjoo
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Joined: Fri Nov 10, 2017 6:19 pm

Re: question about fuel tank petcock and path to carburetors

Postby juntjoo » Wed Feb 28, 2018 3:29 am

Volker_P wrote:
juntjoo wrote:Any ideas before I take it apart again?

Pull the hose from the petcock, put on another hose there, then release some fuel into a jar. This way you get an idea how much fuel could go into your carbs.


yeah I'll do that if I continue to have probs. thanks
82" cb650 Nighthawk


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