Petcock fix

[mac]

Thought that I have read that leaky petcocks can be fixed by lapping. What do you use for the lapping compound ? The reason I ask is that I tried it with valve lapping compound and it seemed to be too coarse and I had to clean them up with 600 grit sand paper. Also,is it normal to not be able to tighten the little nut on the valve very much ? If I get it even a wee bit past snug you cannot turn the valve on or off.Maybe I screwed them up during lapping.I have another set that I will give another try on with further advice. One last thing,any luck with finding a fiber washer locally for the seal at the tank ? I tried o rings but they aren’t working 100%.

[Tether]

I gave up on those petcocks. Every one of several I have bought leaked. Tried lapping with different compounds which helped but not completely. I use these now, inexpensive, made in the good ol’ USA and best of all they don’t leak a drop.
Bob

[Bullfrog]

My experience is pretty much like yours. The original brass (conical spool) petcocks are tough to work with. When I get the nut tight enough to stop leakage, I can no longer turn the petcock on/off. Lapping with BonAmi powdered cleanser seemed to be the ticket. Took a LOT of time. Helped some . . . but still had the problem of having to choose between operating the petcock OR tightening the nut enough to stop the leakage. So for me, brass petcocks are for garage queens - working petcocks are for riders.

My local Ace Hardware has fiber washers. Any good hardware store with a big inventory of fasteners (including metric) should have fiber washers. Pretty easy to drill if larger ID is needed.

Ed

[mac]

Well,I least I know it,s not just me. Thanks Ed.

Bob,I like those,where can I get them ?

[viclioce]

Yes Bob! Please share where you purchase these petcocks!!! My garage floor will love you forever!!! Victor

[thirdstone]

Me too , part supplier and part number please.
I’m forever tightening and fitting new washers and living in fear that it will end in a ball of flames .
I’ve gone down to just one tap, living on the edge I know but I can’t have the chance of fuel dripping on the up pipe or worse dislodging in a crash. . I know I’m paranoid but I’ve seen bikes go up in smoke and it’s ugly.

[matt glascock]

Do those petcocks properly thread in the standard Hodaka toaster tank bung or do you need to tap the bung?

[mac]

Just a bump so Tether might see it before it gets too far down. Also,I did not realize these were an option until seeing them on the HPI site today. I,m guessing they are better than the brass ones ?

[matt glascock]

They are great. I've slowly been changing them all over to the pot metal ones as you've shown. They have yet to fail. What's more, they can be rebuilt.

[mac]

Thanks Matt ! That’s good to know there is fix to the brass that will thread right in.

[matt glascock]

One other thing, Mac. The pot metal petcocks are really soft compared to the brass. I've found it to be a good idea to run a tap into the tank bungs and the threaded portion of the petcocks through a matched die just to dress the threads. Use a good quality fiber washer, like Terry sells - the good, thick red ones, on each mounting and go finger tight plus about a half turn. I snapped the threads off one before it even make contact with the bung which informed the above recommendation.

[givergas]

would thicker gasket material work in place of a fiber washer? ....albert

[matt glascock]

Hi Albert, So long as it is fuel proof you could try. My take: The set-up was engineered to employ a fiber washer. It may have something to do with the density/compressibility of the fiber washer providing a good seal at proper torque. I don't really know. I use them and they have never let me down.

[mac]

What type of 1/8” tap do I need. I remember reading that it was like 1/8” npt but not tapered and I cannot recall what the term for it is.

[rlkarren]

1/8” bpp (British parallel pipe) thread

[mac]

Okay,thank you !

[Tether]

The petcocks I’m using I get from eBay listing number 292003180084. $10.99
They are 1/8 NPT. You’ll need to run the NPT tap (tapered) into the existing hole stopping at a depth that is not too deep. Might take a couple of tries to get the depth where you want it. Some teflon tape.
I also get these filter screens the fit these petcocks from Mike’s XS.

https://www.mikesxs.net/yamaha-xs650-pe ... 70-77.html

Bob

[mac]

Thank you Bob,just what I needed to know. I have been working on fitting this tank as an alternative. I like the look of an original tank,but I have been working on fitting this one as an alternative. Much smaller allowing a tighter turning radius if deemed necessary after riding more.