Ooops. Oil change.

Guess who has two thumb and left the petcock on prim. Thats right, puddle of gas on the floor, and changed the oil just to be safe. (idiot) :lol:

 

i did that last week too : /

 

Did that when i first got the bike, for some reason i didn't know that PRI is not equal to 'OFF'

 

I lucked out. There was no gas in the oil, but it needed an oil change anyway.

 

i definately had gas in my oil it was bad...

 

Correct me if I'm wrong.

But leaving prime on wont cause gas to get into your oil or spill out the carbs unless you have an issue with your carbs such as floats or float needle valves.

 

Ya, that's usualy the case. Though I have often wondered about the effects of the bike leaning on the side stand.

 

ya leaning on the side usually makes it overflow. even if the needles are right.

 

Mine had trouble with that for a while, it had a defective pet cock (which gas treatment only made worse) and also seemed that there was some debris lodged in between the needle and seat. I changed the oil often and although it never smelled of gas, it was the only logical solution to my rising oil level. #4 carb also flooded over night. As a last ditch attempt to get it working right and since I already had moved the air inlet to the side of the air box I wound it up to about 75 mph in 4th wide open with the side cover off and stuffed my fist into the 3" inlet in an attempt to suck the carbs clean (choke the crap out of them) and it worked. The main line in the tank is still clogged so for the moment, I simply leave it on reserve all of the time and it seems to work fine. The needle and seat in the carb works like the float in the toilet, we don't turn the water off over night we trust that the float will close the inlet valve, and it usually does. Carbs work the same way.

 

I too am having petcock problems. My vacume side doesn't work so to ride mine I have to ride in the prime position.This is how my mind works.

Tank holds 4 gallons@ 8 lbs per gallon that is 24 lbs of pressure pushing down. The needle has a tea cup of gas and a very small float pushing up. so with a full tank of gas you have more pressure pushing down than up. Probably doesn't have anything to do with gas getting by the neddle just how my mind works. No matter I am in the process of makeing mine work the way it should so I have one less problem.

 

Precisely. Petcock problems (including being left on PRI) alone won't cause the issue if your carbs/floats are functioning correctly (no matter which stand you're on.)

You have a float issue of some sort.

 

I had the same problem with the fuel filling my cases too, so what I did as a temporary fix was to put a new piece of fuel line with a shut off in it. While I was at it, I extended the fuel line long enough so that it ran into the area under the seat and put the shut off there, what this did was two-fold: made it easier to get at, plus it was my version of a poor mans anti-theft device. If I was parking it for an extended period or somewhwere I was unsure about, I'd shut the line off and run the bike til it stalled, then put the seat on and left. My reasoning was, if they could jimmy the ignition it still would not start because there was no fuel.
Here is a link to fuel shut-offs from a small engine site, you can see how cheap they are.
http://www.mfgsupply.com/SmEngFuelValve ... d=L6HiUzei
I used one like this:

Cheaper than a new petcock and easier than a rebuild, no fuel starvation problems either.


Cheers, Graham

 

Ya, I have one. I took it off when I installed my inline filter and never got around to putting it back on. But that part is only as good as the guy who remembers to use it (which obviously isn't me)

 

I believe

the pressure on the float needle is much less than that. It is dependent on the surface area of the needle and the (height of the fuel) * (density of fuel) * (gravity)

has nothing to do with volume

Imagine a bathtub full of water and you needed to pull the plug to drain it. If volume was a factor all 40 to 60 gallons of water in the tub would be applying pressure to that plug. Then lifting that plug would require lifting 40 to 60 gallons of water. I can't lift that much

sorry thought a lot about this when I was having leaky carbs

 

It's all about surface area. In the fire service we use air bags to lift heavy items. 5 lbs of air spread out over 2 square feet has amazing lifting power. So 16 lbs of fuel pressing on a needle point has almost no bearing at all.

 

I didn't realise carbs had bearings, unless you're talking about NEEDLE BEARINGS!!!
Sorry, I've been cooped up inside all day and it's making me crazy!!!!!!! :x
C'mon dry, sunny days!!!!!!!!!
Woo-Hoo, crazy for Coco Puffs!

 

I hear ya, I'm itching to get back out there. Forecast for tomorrow is snow.

 

Hey guys, the needle and seat should work under pressure, if it didn't the carbs would flood while running. They have to turn the fuel off when the float tops out like on decel or braking with the clutch in. This is my 9th motorcycle and its the first I've had that had a vacum assist to the valve.
Gasoline is lighter than water so 4.5x 6.5 is about 30 psi, but the surface area of the needle and seat is ridiculously smaller than that. Its more like 0.0625 inches wide open. You are more likely to run lean on a low tank than for the gravity to over power a good needle and seat.
I may get in trouble with the administration for suggesting an after market fix but Mikuni has an inline vacum assist fuel pump I've been thinking about installing. I can get rid of that troublesome doo-dah under the tank, run a fuel filter and maybe get something simple (like) maybe a Honda off/on/reserve valve off maybe a CB 750 or 1000.

 

There's always these guys: http://www.pingelonline.com/fuel_valves.htm
A lot of rcers use these on their bikes, On = fuel or Off = no fuel, simple.
They also carry other apps too.

 

Those look nice, but you still have to remember to turn them off.

 

Well you could always leave yourself a note, this was on the back of the numberplate on my old race bike!

 

I thought maybe I could attach a string to the petcock and the keys, but that won't help, I live in Northern Mi, I never take my keys out.

 

My 750 hasn't had a vacuum line since I got the bike . Didn't know it needed one just knew the petcock didn't work right. Along comes a leak and when I check things out I could see the light. This afternoon I installed a vacuum line and low and behold it works like a champ. I am still going to keep a close eye on it.

 

I got my bike back from the mechanic and after leaving it for a couple of hours it wouldn't start. I found the petcock was on PRI and there was fuel all over the ground.

So..... what do I do now? I'm sure the carbs need cleaning out, but is there any tips for getting it started?

That way at least I can get it back to the mechanic.

cheers

 

Before you try to start it, Clean up all of the gas, then check your oil. It may be contaminated. If the oil is ok, pull the spark plugs and turn the engine over a few times to clear out the cylinder. Don't crank it too much, Iv'e heard that it is bad for the TCI. Make sure you're plugs are dry, and it should start (providing that it ran before). Good Luck.

 

Just so everyone knows, your fuel pressure is 1/3 PSI.
This is with a half tank of gas,
where the fuel level is exactly one foot above the needle.
and gas weighs exactly 6 pounds per gallon.
A column of gas 36 inches tall exerts 1 PSI.

 

weird

 

Don't forget to put an old towel over the head, if the cylinder have fuel in them it'll come flying out like "OLD FAITHFUL" at Yellow Stone National Park", and believe me, THAT is a mess!'Don't ask me how I know, ok?

 

Thanks for the tips guys.

This is where i'm at. I tried to start it half a dozen times to no avail. So I changed the plugs. (I was getting a spark). The plugs were pretty dirty.

It still wouldn't start and now the batt is almost flat.

I didn't do much cleaning and the bike got tipped over during the night. I found plenty of fuel on the deck in the morning.

I know its starting to sound like a bit of dogs breakfast but I just really want to get it started so I can take it back to the mechanic and give him an earful.

Is changing the oil the first thing?

 

*EDIT* Fill in your Bio, you never know, a fellow board member may be close by.
Jonathon, what did you take it to the mechanic for in the first place? I didn't see it mentioned in your earlier posts. Also, was it the mechanic that left the petcock on prime or was that something that you did? Did you take any pictures of the fuel all over the ground? What caused the bike to tip over and was all the gas spillage caused by the tip over?
Now, all that being said, how far away is the mechanic that originally looked at the bike? If he's not too far, maybe you can go and see him and explain that after you got the bike home it will not start and you can't get it back to the shop until it's running. Maybe he will stop by, a long shot, but you have nothing to lose and everything to gain.
Make sure the battery is fully charged before he shows up. If you get the smell of gas from the filler cap hole change the oil and filter first.
Now, when you try and start the bike how much choke (enricher) are you using? It seems that every bike can be fickle when starting this way, try it at different positions and turn it it over for a few seconds. Full choke may be too much, half way may make it try but just sputter, 1/8 may make it fire right up and purr like a kitten. It's just a matter of patience until you find which setting works.
Anyway, keep us updated as to how things work out.
Good luck with the bike, don't give up!


Graham

 

I'm In Sydney, Australia. Say g'day if you're near by.

SO I bought the bike and took it to the mechanic to get it registered. I knew the carbs needed some work, it was leaking fuel. We thought it would need a new manifold. After taking it apart he said it was just the seals that needed replacing.

So, I had a glorious afternoon of riding. Then, after leaving it for about 2 hours I went to get on and she wouldn't start. Battery was ok, just didn't catch, choke was at its standard 50% mark, all should have been sweet. I kept trying all the tricks i knew to no avail.

So i left it overnight.

When i came out in the morning it had been tipped over. Not sure how or why, brake lever snapped off, plenty of scratches. I was obviously pissed off, but hey what can u do.

And of course she still didn't start. And now the added complication of potential fuel in the oil.

So, first i need to get the battery charged, then i'm thinking an oil change.

From there what advice or checks can people recomend.

Thanks guys, you rock.

J