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 Post subject: fuel cock
PostPosted: Fri Dec 29, 2017 6:08 am 
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For the avoidance of doubt can someone please tell me the correct way to connect fuel pipes to the petcock. Top, middle right and bottom for the larger diameter hoses.

Is the top point the fuel hose to the carbs?
Bottom point of fuel petcock connected to "On" side of fuel tank?
Middle right point of fuel petcock connected to "Reserve" side of the fuel tank?

Thanks in advance.


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 Post subject: Re: fuel cock
PostPosted: Fri Dec 29, 2017 8:58 am 
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According to my CAD data it should be marked on the parts how the hoses needs to be connected:

Image

Image

Image

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 Post subject: Re: fuel cock
PostPosted: Fri Dec 29, 2017 10:56 am 
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Thanks SpeadFreak.... Perfect!


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 Post subject: Re: fuel cock
PostPosted: Mon Jan 01, 2018 3:07 pm 
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hello there,
I am trying to do the same. My only question is what is the 4th small spigot for on the petcock? Is that an overflow tube? Or how should that one be routed? thanks much for your time.


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 Post subject: Re: fuel cock
PostPosted: Mon Jan 01, 2018 4:07 pm 
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Image


Last edited by jackson.40 on Sat Apr 21, 2018 2:56 pm, edited 1 time in total.

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 Post subject: Re: fuel cock
PostPosted: Mon Jan 01, 2018 4:19 pm 
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The small one is vacuum, connected to the one carb which has a spigot.

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My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: fuel cock
PostPosted: Wed Jan 03, 2018 10:56 pm 
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Hey there; thanks for the reply and photo. My bike has 34mm Mikuni's installed, so there is no spigot for the vacuum line. Can I just put a stopper on that spigot on the petcock or does it need to have air? Some type of check valve maybe?
Appreciate your time with helping a noobie; just purchased the bike and it has pingel petcocks on it that bypass the factory petcock.


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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 2:11 am 
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Vacuum opens the diaphragm to allow fuel flow in the ON and RES positions. No vacuum means no fuel flow.

You can plug the vacuum port and run with the petcock on PRI (prime) but you'll have no reserve.

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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 6:04 am 
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There is a possible modification to change the vacuum operated part to a simple on-off-(res?) part.
I want to do this mod on my bike as I don´t like this vacuum actuated stuff.

I will check in CAD in the evening what needs to be changed.

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RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 6:44 am 
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Speed Freak wrote:
There is a possible modification to change the vacuum operated part to a simple on-off-(res?) part.
I want to do this mod on my bike as I don´t like this vacuum actuated stuff.

I will check in CAD in the evening what needs to be changed.


There is a thread about this mod. Just looking for it ....


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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 7:05 am 
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http://www.rzrd500.com/500phpBB3/viewtopic.php?f=10&t=14972&p=90774&hilit=Petcock+mod#p90774


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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 4:43 pm 
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Has anyone a suggested way to keep the OUT spigot securely in the petcock? Mine pulls out easily by hand.
Maybe JB Weld??


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 Post subject: Re: fuel cock
PostPosted: Thu Jan 04, 2018 5:04 pm 
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I have the same problem. You can pull out all spigots.

JB weld should be fine as it is fuel resistant (heard that it is often used to form inlet ports and crankcases).

Or maybe something from Loctite:
http://tds.henkel.com/tds5/Studio/ShowP ... lant=WERCS

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My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: fuel cock
PostPosted: Sun Feb 18, 2018 4:04 pm 
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Hello there,
I was hoping someone could help me see where I went astray on my petcock mod. I attempted Rick's mod to the petcock plunger, pressing it into place until it was stationary but when I tested it out and turned it to the on position, fuel flowed out of the small hole that is on the bottom side of the hard rubber gasket (the hole is right by the outlet spigot).

I took the cover off and examined it and the plunger seemed to not be fully seated, so I pressed it in some more but ended it up distorting it and basically making it useless!

I guess I have two questions if any one can help me:
-has anyone else ever had fuel come out of that small hole? what did I get not right?
also; is there a source for the parts that I buggered up?

I much appreciate anyone's help on this and thanks in advance.


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petcock plunger.jpg
petcock plunger.jpg [ 134.82 KiB | Viewed 945 times ]
petcock rubber.jpg
petcock rubber.jpg [ 110.84 KiB | Viewed 945 times ]
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