Special Petcock Mod

[crazy steve]

Ok, here's my as-promised Special petcock mod.... super easy!

[IMG][/IMG]

This will convert your petcock to full manual, and eliminate the 'prime' position (converting it to another 'off'), as well as sealing it. Simply run a 5m.8 tap into the 'prime' feed hole as shown (you don't even need to drill; it's big enough), then thread a same-size set screw into it. I used a 10mm long screw, but a 5mm would be better and don't run the tap in as far as I did. Thread it just deep enough so that the screw goes in flush. I put some teflon tape on, and it's sealed. If you want to reinstall the octy, just pull the screw.

The rubber cap is just for 'finish' and to keep the spigot clean for future; gas won't get to it. The screws were only $.75 for both.

This could also be done to the standard petcock (with a larger screw), but would require other internal mods. And if you want to replace those always-rusty small screws that hold on the chrome cover, run a 6-32 tap through the holes and use some stainless buttonheads. Again, you don't even need to drill (but you do need to enlarge the holes on the cover), just run the tap through. You can do this to either type petcock...

[SFerinTEXAS]

Not trying to sound rude but what exactly is the point of this? I am running my XJ with out the prime or octy. Just rear feed directly to the carbs. Left carb to the right tank and right carb to the left tank. I must be missing something. Great work here but I'm missing the point. Sell me on it.Don't go getting offended please. What am I missing? I run a fuel hose from the two prime tank ports together in case of a petcock leak.Or just cap them off. I can see this with a std just not a special .Seems like a better mousetrap that has no mouse to catch. Not known for being politically correct.

[DGXSER]

The point being you do not need that cross connect hose between the primes, or any other method of ensureing gas does not leak if you accidentally turn the petcock to prime position.

My question is, will the teflon tape hold up to fuel?

Personally, I like this. Not something I am going to go out and drain my fuel tank to do, But I might not fill it up next time I am pretty low on fuel and then I can just lean the tank to get the fuel away from the petcocks, and work on them on the tank. Even if the teflon tape is not fuel proof, how often will it see fuel (if your petcocks are in decent condition and operating correctly). Should work nicely.

[MrOzz]

Nice mod Crazy Steve.


Also great idea on the chrome cover screws running a 6-32 tap through the holes and use some stainless buttonheads. Think thats what I will do when I winterize my bike this year.

Ozz

[crazy steve]

...sell me...I run a fuel hose from the two prime tank ports together in case of a petcock leak. Or just cap them off...

You answered your own question; you don't need to run another hose between petcocks, or cap them. You can't cap them with vacuum caps unless you do this mod (the caps won't take the fuel exposure; Phil already tried that). This is cleaner, less farmer-fix...

As to the teflon tape, it won't see any fuel flow so should be fine. Or you could use a fuel-proof pipe dope.

By the way Don, I did your gas cap fix with the t-stat gasket... worked slick! Thanks! Oh, and if the local parts store doesn't sell Fel-pro, Phil's posting of it being for a '85-95 4 cylinder Camry is correct.

[fredintoon]

- - - - My question is, will the teflon tape hold up to fuel? - - - -

Hi DGXSER,
teflon is just about chemically inert and holds up to anything. Except for radiation, where it's worse than almost everything. So unless you are running radioactive fuel (which I doubt as the lead shielding on the tank would make the bike unacceptably top-heavy) You'll be fine.

[SFerinTEXAS]

Sorry. this is novel but silly. You are saying I can get a 5mm tap and some setscrews and not have to hook a hose between 2 fittings. SORRY THIS IS SILLY.

[SFerinTEXAS]

This is cleaner, less farmer-fix

I take an exception to that comment.Hope I'm not alone its just practical

[DGXSER]

SFer, I took an even simpler solution to it myself. I used a piece of fuel tubing and put a screw in the end of it. I just never turn the petcock to prime. It is natural for me to turn from off to on and back without even thinking about it now. And I almost never need reserve, so it is a non issue. But I do like the thought of it being sealed off inside the petcock. As to the fuel line run between the petcocks, a decent simple solution as well. Only an issue when you go to remove the tank I would think, but petcocks are off then anyway.

This is surely not a solution to a problem that has torubled the XS community for ages, but it is a nice answer to an issue that has been dealt with less technically in the past.

[SFerinTEXAS]

There is no simpler solution. than the one I have stated.

[natemoen]

There is no simpler solution. than the one I have stated.

If you don't like it then dont do it...simple as that.

[Shacknasty]

"Everybody needs someone to look down on." Kris Kristofferson

[crazy steve]

SORRY THIS IS SILLY.

Let's see, a foot of fuel line (what, a buck, buck'n'half? More?), and two hose clamps (probably the same), and a chance of dribbling whatever fuel may be in that line on the bike every time you remove the tank.

Versus $.75 for two set screws (hey, I already have the tap). Hmmmm... tough choice....

[fredintoon]

Sorry. this is novel but silly. You are saying I can get a 5mm tap and some setscrews and not have to hook a hose between 2 fittings. SORRY THIS IS SILLY.

Hi SFer,
if one doesn't already have a metric tap set and an arm-length of fuel hose on hand one should have, so no contest there.
Internally plugging the prime port is an elegant alternative to a short length of fuel hose with a ball bearing shoved up it.
Bridging the prime ports is quick and easy but the hose gotta be unhooked and put back on each and every time you take the tank off.
What's SILLY is those double-dick gas taps.

[crazy steve]

What's SILLY is those double-dick gas taps.

Fred, the more I work on these bikes, the more I wonder at some of the design decisions Yamaha made... the Special petcock arrangement is the most inexplicable one of all. They had a nice, simple design in the standard petcocks (one fuel hose and one vacuum hose each) and felt the need to redesign into a system with more parts and a maze of hoses under the tank. And changing the mounting base so they won't interchange, what was that about?

Some sort of perverse revenge on the roundeyes?...