No Fuel?

[Grimly]

Both of these ideas make sense. I was using the throttle with the choke on, so I was doing that wrong.

Old habits die hard, in my case. In my early years I had bikes with manual chokes or ticklers and I was in the routine of cracking the throttle open just a touch as I kicked it over - each bike needing a slightly or even wildly different technique.
I find myself STILL doing it unconsciously, many years after not needing to do it at all.

[Anthony]

Well, I tried to do a fuel IV with a bottle, and it flooded the engine. I started popping really loud. So then I cleaned the spark plugs and tried putting the line in the gas can again, and then it started right up. The idle was very high, around 4000 rpm. So I thought the idle screw was wacky, but i forgot which way to turn it to lower the idle, and I can't see to see how far in it is. I didn't even use choke when it finally started running, so I think the pilot screws are letting too much fuel in. Is all that typical of a first run? It died after I tried adjusting the idle, it fell too low and then was flooded again.

[Steve]

Well, I tried to do a fuel IV with a bottle, and it flooded the engine.

How high did you have that bottle?

The height of the fuel in the bottle should be about the same height as the stock gas tank.
If you go much higher than that, there might be enough pressure ("head height") to overcome the float valves.

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[Anthony]

I had it at gas tank level for 5 minutes of cranking, but it wasn't doing anything. So I held it higher up, and then it started to make noises for starting, and that's when it flooded. Is the fuel IV really the best way to do it? When I cleaned the spark plugs and used the gas tank again, it fired right up. I thought that wouldn't work since it's gravity fed?

[Steve]

Call it a "fuel IV", "aux. gas tank", whatever, it just needs fuel that is about the same height above the carbs as the stock tank. Depending on how far away your bench is, you can even run longer hoses from the tank on the bench to the bike, it doesn't really matter.

By the way "5 minutes of cranking" is hard on the bike. The battery, the starter, pretty much everything. You shouldn't need to crank for more than 5 SECONDS at any time, even when starting an engine from a fresh carb rebuild.

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[Anthony]

Well 5 minutes of 5-10 seconds of cranking. Basically fiddling with it for 5 minutes to try to get it to start, not constant cranking. How else am I suppose to do it? If it won't start, how do I get it to? Maybe now that it ran for 5 minutes, it will start like normal the next time I start it. Will a hose in a gas can that is at stock level work, or will I still need to do an IV method?

[Grimly]

If you put the tank on a table at the right height, that'll do. If your float valves are seating properly, they'll withstand a much higher head of fuel than the normal fuel tank height in any case, so I'd be inclined to look more closely at them. You did replace them?

[Anthony]

No I didn't replace my float valves, nothing was wrong with them at the time and visual inspection indicated that they were fine. I didn't read anywhere that they should be replaced when re-building. Steve said that placing the fuel higher can overload the valves and then it floods the engine, which happened in my case, so I guess that's suppose to happen.

[Grimly]

No, it's not. Put it this way, a typical float valve of that type was perfectly capable back in the day of sealing off a low pressure fuel pump of 5psi, which is about the equivalent of 10ft of head - and more besides. Either your floats are wrong or your valves are.

[Steve]

Steve said that placing the fuel higher can overload the valves and then it floods the engine, which happened in my case, so I guess that's suppose to happen.

No, I didn't mean that it's supposed to happen when you do that, only that it's more-likely.

Keeping the fuel height closer to stock levels minimizes that possibility.

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[Anthony]

Well it keeps flooding. I left the fuel IV at stock level and it still flooded it. So then I did the gas can again, and it worked for a couple minutes, idled at 4k, and died. Did this twice. Cleaned the plugs again, and put the pilot screws at 1 and a half from lightly seated. Now it won't start at all. I'm getting very frustrated, tonight was one of my few nights off to do testing, and I can't even get it running to do a carb sync and adjust the pilot screws properly. And I also am having a hard time with the master idle screw, as I can't see and don't know how far in it is. Can anyone help? :/

[Grimly]

If your float needles are letting too much fuel past, you can fiddle and fart around till you're blue in the face, but you'll never get a stable condition.
Not the first time an owner had visually inspected needles and seats and thought they were fine (me too, and I used to do it for a living) and the only cure was a new one/set/however many needed.

[Anthony]

So I set the pilot screws at 3 turns out, and it still is not starting. It's acting like it can't get fuel, but if I do a fuel IV, it just floods everything.

[Anthony]

Also, if it is my float seats or valves, how do I know? What should I all replace to be safe?

[Grimly]

If they're all brass on the needles, they can be lapped in, but not too much. If there's a Viton rubber tip, that's ruled out. The little spring on the end often goes weak, too. As for the floats, if they're not leaking, they're probably ok, but check them carefully for distortion and bent or cracked/weak tangs where they bear on the needles. The floats should be a nicely loose fit on the securing pins so they don't stick.
There you go.
It's perfectly possible to check everying out and it still leaks, and the only cure is new needles and seats - they must always be replaced as a pair, never individually.