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I have a carburetted Monster 750 with a vacuum petcock. The tank has been drained. Does anyone know how to prime the float bowls without pushing the starter button?
 

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you could pull the spark plugs and rotate the engine a few times, I imagine that would do it... but are you asking with the tank empty how to do it?

The only way other way to do it that I can think of without the pump would be to force gas up into the supply line with a hand pump or something...

how come you want to prime the floats?
 

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Not only does the bike have a vacuum petcock, it also has a fuel pump that is vacuum operated. You could just get a hand-held vacuum pump and connect it to the petcock vacuum hose to open it, but that still will not operate the fuel pump. The easiest way to start a bike that has empty float bowls is to get some quick-start spray (ether) at your local car parts store. You can spray a couple of shots into the airbox and the bike will start and run for a short time. It should only take a couple of times before the fuel pump picks up fuel and supplies it to the carbs.
 

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If you just want to start the engine, use starter. Gas will be in carbs in 2-3 secs.
If not for start, use starter w/o plugs.
If not for starting why do you want to prime the bowls?
Is the tank still empty?
 

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wouldn't you need the plugs in the cylinders to generate the vacuum required to actuate the fuel pump/petcock?

i just recently used this method to prime the carbs on my '96 monster 900. take a length of tubing and attach it to the petcock vacuum nipple. then then put the other end in your mouth and give it the old suck/blow using your cheeks (yes, i know it sounds totally gay, but it works) the fluctuating vacuum pumps the gas through the fuel hose and after a few seconds you will hear the gas squirting into the carbs.
 

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you could always just do it the old fashioned way and pour gas down the intake, but it really depends what you're trying to prime the float bowls for.

Justin
 

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Discussion Starter #7
greenmonster said:
If you just want to start the engine, use starter. Gas will be in carbs in 2-3 secs.
If not for start, use starter w/o plugs.
If not for starting why do you want to prime the bowls?
Is the tank still empty?
I need to prime the carbs because it takes more than 2-3 seconds to get gas into the float bowls. It takes long enough to drain the battery. I had recently emptied the tank for restoration.
 

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yeah, i just emptied and removed my tank for some work too. i also have a dieing battery. i tried the carb cleaner prime and it didn't work, not because it wouldn't fire the engine, but because the vacuum hose that feed the petcock had broken.

so i could get it to turn "run" off a small squirt of carb cleaner, but since the hose was broken the vacuum wasn't actuating the petcock. as soon as i fixed the vacuum line and manually (orally) primed the carbs it fired right up!
 

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I just pull the air filter and dribble some gas straight down the carb throats. It's usually enough to keep it running long enough until the pump can get primed and start feeding the bowls.

The Army always preached against using ether/starting fluids. Something about it washing the oil off the cylinders or damaging the engine. I never got it but when your diesel wont start during November field exercises in Germany you did what you had to do.
 

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J_C said:
I just pull the air filter and dribble some gas straight down the carb throats. It's usually enough to keep it running long enough until the pump can get primed and start feeding the bowls.

The Army always preached against using ether/starting fluids. Something about it washing the oil off the cylinders or damaging the engine. I never got it but when your diesel wont start during November field exercises in Germany you did what you had to do.
The problem with starting fluid is it has has an octane rating of approximately zilch, and when used unwisely. I etherized a lawn mower once. It wasn't pretty. Go with a gasoline prime.
 
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