Later models had vacuum petcocks. I’m fuzzy on what year that started but perhaps your PO changed them out?
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PHANTOM RESURRECTION 78 SPECIAL
- Thread starter The Phantom
- Start date
The Phantom
XS650 Enthusiast
Hey all! Just finished base coat clear coat of these here. Came out awesome, right before the cold snap. Here is a new problem. No filter for one Petcock.
So, you have two petcocks and they’re OEM vacuum operated, correct? At least some of those nets are available from OE parts dealers. Alternatively, you only need one petcock. Block off the one on the right. Put the screen to the left and plumb it to both carburetors. It will function just fine.
If it were mine, I’d make the effort to find a net and rebuild both petcocks. Functional vacuum petcocks are very nice to have. They train you to leave them alone.
Just temporarily run with a cheap aftermarket non vacuum and a small K & N inline filter till you can rebuild your OEM set-up!
That paint sure looks nice
Beautiful paint job, congratulations! 
Happened to my single petcock XJ650. I cleaned it up and used Seal All to put it back and then rebuilt it.
I played around with various china made petcocks with that bike and some of them just come with brass tubes and a screen on the top.
That is what I'm using on my XS650 right now, its a non vacuum petcock and when I'm done rebuilding the originals, they are going back in the bike.
I really like the proper full size screen.
I’m running that on my XS650SH. It’s the manual replacement MikesXS and everyone else has. It’s not a simple swap. The outlet is 3/16”. The carburetor inlet is 1/4”. The outlet was at the wrong angle, so I had to shim it to the correct position. I lubed the rubber disk with Parker Lube (I believe dielectric grease would be fine for that.) So, the handle now moves freely. I raised the screens and secured them with .020 stainless safety wire per @rhkansas. Works fine after a PITA replacement. I’m still going back to the OE vacuum. It’s just better.
The Phantom
XS650 Enthusiast
I painted them in my brothers front yard. Got a nice DeVilbus paint gun off eBay cheap during Covid. Just took my time. Pretty huge dents had to be filled with fiberglass and bondo. I’m in no rush. That makes for a better prep.
This is what I'm running temporarily. I got 2 of them and yes, you can run 1 if you can fashion to plug the other tank opening (I 3D printed covers for when I did the vinegar de rusting). These you can configure which side the outlet is on. the angled outlets are useless cause you use the straight ones and the angled ones you can't configure the angle.
Yes, I had to use smaller fuel tubing, I already had the smaller tubing from another bike rebuild last year and you need to really work it to get the smaller tubing onto the carb inlets. I don't like the tiny screens as mentioned and If I was going to run this long term, I would have used seal-all on the filter to brass. I had to carve out the plastic to get the brass to fit, (thought about heating it up but just carved it out)
https://www.amazon.com/gp/product/B07SWJ4N9J
Yes, I had to use smaller fuel tubing, I already had the smaller tubing from another bike rebuild last year and you need to really work it to get the smaller tubing onto the carb inlets. I don't like the tiny screens as mentioned and If I was going to run this long term, I would have used seal-all on the filter to brass. I had to carve out the plastic to get the brass to fit, (thought about heating it up but just carved it out)
https://www.amazon.com/gp/product/B07SWJ4N9J
The manual petcock that Melnic is using is only half what MikesXS is charging for what seems like the same item, here is Mikes:
I've had one of these installed for 3 years, and its been working fine.
I did a write-up on the installation which is in the Tech section:
https://www.xs650.com/threads/installing-mikesxs-non-vacuum-petcocks-on-later-models.50124/
.
I've had one of these installed for 3 years, and its been working fine.
I did a write-up on the installation which is in the Tech section:
https://www.xs650.com/threads/installing-mikesxs-non-vacuum-petcocks-on-later-models.50124/
.
Petcocks. I ran out of fuel on the "Red Bike" some months ago. I was 1/4 mile down hill from a gas station. Walked to the gas station but they had no "lender" gas cans. I fished a Penzoil 1 qt oil bottle out of the trash, filled it almost full, walked back to my bike. The right sid fuel cap had me leaning the bike to the left to get that precious quart of fuel to the (aftermarket) petcock. I turned the lever "up" for reserve and no fuel flowed through my Tygon clear yellow fuel line. When I turned the lever "down" to "ON" the fuel flowed through the line. I had always thught that it was the reverse.
Good info to hear Yamadude.
Having been a long time advocate of original 78/79 vacuum petcocks, I must admit that this summer mine has a slow drip when parked. So I’m looking into fixing that today. I drained my rust free tank after work.
This unused aftermarket petcock set I’ve had in a box are being looked over and I actually like them
I read the fittings were smaller than Yamaha so I went straight there for a test fit with the fuel line I use and.. tada it’s a great fit!
Probably going to install this set on the now empty tank and test em
Attachments
I bought a set of the Chinese repops and noticed two things. The lever cock positions were backwards and they leaked. I took them apart and reassembled and got the wave washers to seat better. Resolved the leak but have to remember which way is correct to turn them and not put them on RES. The dead giveaway is the smell of gas in the garage. Lol
There is no “lft” or “rt” as they both have the same part #
You do reverse one of the outlets to the opposite side of the casting, but of course the “on” “res” “off” positions must be paid attention to on opposite sides of the tank.
You do reverse one of the outlets to the opposite side of the casting, but of course the “on” “res” “off” positions must be paid attention to on opposite sides of the tank.
LTGTR
XS650 Addict
What is the logic of the taps - does the handle point to the position or the other end of the handle - I didnt explain that too well.
In the picture above are the taps on "On" or "Reserve".
Thanks
Ray.
In the picture above are the taps on "On" or "Reserve".
Thanks
Ray.
I believe those are in the ON position as the handle points in the direction of the desired position.
Agree, handle is the position indicator, up is RES. Post in #97 is ON.
One thing I don't like is the O ring. The screws are not isolated like on a stock petcock O ring that has the lines between them.
Thus the ONLY thing stopping fuel from going through the screws is the sealing washer, Unlike stock petcock, you can use sealing tape on the threads to belts/suspender the sealing washer.
As shown in post #95, there are additional filter screens that go into the bottom between the 2 brass fittings (plug on one side, outlet on the other) Gotta make sure its inside the outlet and not crushed as you put it together or you will not get the filtering feature
I just finished up rebuilding my 2 stock petcocks yesterday on my '78 special. I'm not going to install them right away though. I want repaint my tank.
One thing I don't like is the O ring. The screws are not isolated like on a stock petcock O ring that has the lines between them.
Thus the ONLY thing stopping fuel from going through the screws is the sealing washer, Unlike stock petcock, you can use sealing tape on the threads to belts/suspender the sealing washer.
As shown in post #95, there are additional filter screens that go into the bottom between the 2 brass fittings (plug on one side, outlet on the other) Gotta make sure its inside the outlet and not crushed as you put it together or you will not get the filtering feature
I just finished up rebuilding my 2 stock petcocks yesterday on my '78 special. I'm not going to install them right away though. I want repaint my tank.
