Author Topic: Petcock  (Read 1197 times)

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Offline shizzomynizzo

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Petcock
« on: May 15, 2010, 09:05:38 PM »
HI everyone,

Just got my 550 out for the first time this year. I put a 750 tank on it, and it has a single output (on the bottom of the petcock). My carbs were set up to receive 2 lines from the petcock. I put an inline "T" fitting in order to make it "work" and now the bike is having some flow issues. I figured the siphon created from the gas flow would overcome any flow issues from bends up and down in the fuel line. Apparently it wont.  

Does anyone know the thread size of the petcock bung on a 750k (believe the tank to be an early 74)? I think if I can find a side discharge petcock that is compatible, I can avoid all the bends in the line.

Thanks,
Shizzomynizzo
« Last Edit: May 15, 2010, 09:27:20 PM by shizzomynizzo »
1974 CB550
1985 XLX Last of the IH
2001 Street Glide

Offline manjisann

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Re: Petcock
« Reply #1 on: May 15, 2010, 09:47:19 PM »
I ran into the same issue, a 650 tank and petcock with 750 carbs. To overcome the kink in the line issue I made a special t, and it seems to do the trick. Got the parts and Lowes. To get it all to fit together snuggly you'll have to chop the threads shorter and then file them down so they fit inside the T then pipe solder it all together.

Sorry, doesn't answer your question, but if you can't do the petcock thing, this is a decent alternative.

HTH

Brandon
Sure it's for sale! How much you ask?? Well, how much are you willing to pay??? Now triple it, that's the price!

1973 CB500 K2 - Sold the bike and bought a Mig, Miss the bike, Love the Mig :D
1980 CB650 Custom
1971 CB500 Frame 650 engine: Project

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Offline Fabricator

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Re: Petcock
« Reply #2 on: May 16, 2010, 05:32:32 AM »
The ID of the petcock attachment tube is perfect to tap 3/8" NPT.  It will then accept a "Hardly-Davidson" petcock, and these are available in a right angle configuration.   This is what I did, and my reserve works out perfectly.   If your tank has the bolt-on petcock, there are adapter plates availabe to convert it to 3/8" NPT, and still employ the aforementioned solution.  The HD sportster petcocks are only about $15 FWIW.

Fabricator
"When in doubt, gas it. This; to be honest, doesn't always solve the problem, but at least it ends the suspense." (Mark Gardiner from "Riding Man.")


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Offline shizzomynizzo

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Re: Petcock
« Reply #3 on: May 16, 2010, 09:38:35 AM »
The ID of the petcock attachment tube is perfect to tap 3/8" NPT.  It will then accept a "Hardly-Davidson" petcock, and these are available in a right angle configuration.   This is what I did, and my reserve works out perfectly.   If your tank has the bolt-on petcock, there are adapter plates availabe to convert it to 3/8" NPT, and still employ the aforementioned solution.  The HD sportster petcocks are only about $15 FWIW.

Fabricator

Exactly what I was looking for. Thanks Fabricator!
1974 CB550
1985 XLX Last of the IH
2001 Street Glide