idea

[bikerphil]

I'd have a seperate in line fuse for that valve just in case, JMHO.

[Nightengale]

My turn to play the Grinch.

With an orifice of .156, slightly larger than 1/8 of an inch, and having only about a foot of head pressure, (ignore the sex maniacs response to THAT,) if you try to feed both sets of two carbs through one valve, you may run into an adequate fuel flow problem.
A valve for each set of two carbs would help.
At any rate, a fuel flow test before test ride would be in order, and over size fuel lines before and after the valve wouldn't hurt.
Assume a fuel use of .5 lbs/hr/HP, and lets be real generous and say 100 HP, (hoping that none of our Northern neighbors call us on that "guesstamate",) it seems that we need at least 50 lbs an hour to run full bore. At 6.25 lbs a gallon, you would need 8 gallons an hour. Divide by 60 minutes, you get .13 gallons a minute. With 128 ounces in a gallon, multiplied by .13, we get 17 ounces a minute, or lets round off to two cups, or one pint, (to make it a recognizable quantity to our British members,) a minute.
Now this is at full bore, and if you never exceed half throttle, you could get by with less flow, but if your fuel mileage isn't up to snuff, and it is a hot day, fighting a severe head wind on a 10% uphill grade, towing a trailer, and your two hundred pound sweety riding pillion, you might be in trouble.
Let us know how it flows.



Now back to your usually optimistic cohorts.
It is still snowing.
CZ

i was planning on running two of them, as far as the flow rate, i thought that if i go with one that has the same inner diameter as the petcocks that it would not effect the flow rate, since it is just a valve and not a fuel pump. but i could be wrong. that is why i posted this here. the one that i posted earlier is the first one that i saw, but they do have other sizes as well. if the flow rate is going to be a problem i might use larger diameter fuel line.

[Nightengale]

I'd have a seperate in line fuse for that valve just in case, JMHO.

i had thought of that, and i do think i will do that.

[Nightengale]

maybe this one

would this work better
http://www.dan-marc.com/79-afc1211412.html

[Petersg_99]

well, if you're willing to wait, you can see how it works on my bike. I figured I'd start with one, if it's adequate, great, if not, I'll have to get a second one

As far as fuel consumption goes, I come up with the following:

if you get 30MPG at 60MPH, that's
2 gallons/hour

2G * 128oz/G = 256 oz/hr

256oz/hr / 60min/hr = 4.2oz/min (wow, the bike gobbles up half a cup a minute!!!)

4.2oz/min / 60sec/min = 0.07oz/sec.

[CaptonZap]

would this work better
http://www.dan-marc.com/79-afc1211412.html

You might want to check with the supplier and make sure that the valve will work with 0 pressure.
This one is rated for 3?? psi, and some of the high pressure models use the flow pressure to close and seat the valve.
At low pressure, they do not all shut off reliably. Check with the nanufacturer.

CZ

[Nightengale]

Thanks i will

[Nightengale]

found

i did find some that will run a 0psi still have to do some more research but i am determined to make this work.

[Cuda 69]

wow,I got a headache.

[CaptonZap]

i did find some that will run a 0psi still have to do some more research but i am determined to make this work.

Just to make your life a little easier, or not, I did some calcs and came up with .162 psi for head at near empty in reserve position. Basically 6in of head. Twice that when full.
Thats with a standard tank on a 79.
CZ

[Nightengale]

Thanks that does help

[Petersg_99]

The valve you originally posted showed working pressure of 0 to 30psi.

I'm pretty sure one of these valves will be adequate.

[BA80]

Ha ha ha........Hey CZ, when was the last time you rode full bore for an hour?

[trbig]

That is a good new way to get off . However it has exposed many XS1100 guys as worring too much about a new way to get off when there are tried and proven economical ways. Steve came up with a mod some time back that creates a mechanical off in the petcock. They make little plastic off/on inline mechanical switches that do the same.

The real issues are the carbs having issues and adjustment is part of it. Filters in the lines also will help keep trash out. Additives that counteract the effects of methanol and reduce rust in tanks as well as water also prevent the floats sticking. Other issues are leaving the bike idling in the sidestand or for some leaving it parked on the side stand where the float slides over and hangs open. There is also doing a good job rebuilding the petcocks with a good quality kit.

Personally I would rather not have an electrical device near my gas but what ever it takes to get you off I wish you success.

Me I just want the weather to turn so I can get on and ride!!!!!!!!!!!!!! I never have petcock problems while riding

Great stuff for the mechanical aspects of the petcocks, but what about the whole point of the original post about FORGETTING to turn off the petcocks? No, forgetting shouldn't matter if everything is functioning properly, but many times, you don't know there's a problem until you either (Best option) see a big puddle under your bike or (NOT the best option) ride the bike with a crankcase full of gas and ruin the motor/bearings. $25 to make sure you don't ruin your motor seems like cheap insurance. If you're worried about electrical parts near your fuel, you better stay away from nearly every modern car since the electric fuel pumps are in the fuel tank submerged in fuel. Also, on your bike, your tank is sitting on your R/R unit, along with assorted electrical currents, so better not fire that up either.

[Nightengale]

fuel flow

On my bike i have fj1100 carbs which uses a larger diameter fuel lin. My set up is 1/4in. Line off the petcock to a fuel filter, then the 5/16 line going to the carbs. How would this set up effect fuel flow if i use the 1/8 inch shut off valve in place of filter?