Blowing her to start?

[DanTheMan]

Flooding out means you're getting too much fuel and not enough air for combustion. If a carbureted engine (or any other for that matter) has too much fuel and not enough air, the spark plug cannot provide enough spark for combustion in the cylinders. You need the whole fire triangle for combustion to happen, fuel, oxygen & spark. Anyway, I'm digressing.... if your air filter is really dirty, it can cause a lack of airflow, causing an overly rich mixture to enter the cylinders. Try starting it with the filter removed, see what happens. If it starts, it'll probably run like crap, because it'll be too lean, but you'll know that you should replace or clean the air filter then anyway.
Hope this helps.
Dan

[maro]

Flooding out means you're getting too much fuel and not enough air for combustion. If a carbureted engine (or any other for that matter) has too much fuel and not enough air, the spark plug cannot provide enough spark for combustion in the cylinders. You need the whole fire triangle for combustion to happen, fuel, oxygen & spark. Anyway, I'm digressing.... if your air filter is really dirty, it can cause a lack of airflow, causing an overly rich mixture to enter the cylinders. Try starting it with the filter removed, see what happens. If it starts, it'll probably run like crap, because it'll be too lean, but you'll know that you should replace or clean the air filter then anyway.
Hope this helps.
Dan

I hope it's that simple. My only though here is. ALL day long... beyond the morning startup...she fires with perfection. It's only after a cool, dewy night that the start-up is an issue. So . . . if it was a clogged air filter, wouldn't start up be an issue everytime? oh and thanks!

[DanTheMan]

You've probably got a float valve or 2 leaking, allowing the fuel in the carburetor bowls to flood the cylinders (common problem), and your petcock could also be leaking, worsening it. If you don't have an off position on your petcock that's probably the cause. By now, your oil is probably diluted with gas and should be changed.
You should only have gas flowing to the carbs from the tank when the bike is running. Make sure your petcock is in the "on" position and not the "pri" position. If it has an "off" position, it should be off when parked.

[arcturius]

Could condensation on the filters/inside the carbs be causing an initial breathing problem?

[Sandy]

There's a good chance the choke fuel jet in the floats bowls are plugged from debris in the float bowls. This would prevent fuel from being available for proper choke operation. Blowing in the vent tubes would momentarily pressurize the fuel and most likely force some fuel out the idle circuit allowing the bike to start. The slide #77 shows this jet http://www.thegsresources.com/gs_carb_07.htm which is very small and easily plugged, if you're really good you can probably get the float bowls off without removing the carbs. Like mentioned before, the bike should start easily in cold temperatures.

[Zooks]

If your bike likes getting blowed it's probably not a "she/her"

You've just been hanging out with the wrong women.

[almarconi]

Have you made any progress on this? I am going through the same issue with my 750L. First start of the day requires a puff on the vent tubes. I too have done the carb cleaning, valve adjustment, petcock replacement, new coils/plugs/wires..etc and the problem still exists. Since we are getting close to the end of the riding season I'm just going to live with it and ride the bike. I'll probably go through the carbs again over the winter to make sure they are clean. The problem is frustrating to say the least because the bike runs really well once it is started.

[Jon]

I am no expert, but have a similar problem. My 81 GS750 stays out all the time. A well charged battery gives me better cold starts. Stronger spark?
Mine needs lots of choke, but be careful not to flood it....
I suspect the compression may be lower after sitting for awhile and on cold days. Maybe there is less oil on the rings, thermal contraction, etc.?

[maro]

I got to be honest. It's a friggin mystery to me. I've been riding almost every day, it's maybe happened once this month. even the days when the bike has been sitting for a couple days and it's rained, she's been firing right up.

The only thing I've been getting into the habit of, that might be different is that I now pull the choke ALL the way out (in the morning) and with out throttle, let it crank a few times. It will eventually catch and fire. I think before I was not letting it crank long enough.

Honestly, like I said, it's a mystery.

[trappermcnutt]

where to blow?

my girl is an '82 gs650 with a similar problem. where do i blow to get her going in the morning?

[supersonictoys]

your choke system is designed to only work with the throttle all the way closed, otherwise the small inrichment opening in the carbs venturi will not receive enough vacuum to pull fuel up from the bowls when the choke is applied. also, the idle speed being to high can keep your carbs choke system from receiving enough vacuum to operate properly. try it again cold with NO throttle at all and full choke. if this doesn't work I would consider pulling the carbs and cleaning the choke circuits in the bowls as someone else already suggested.

[Don-lo]

I agree with Sandy. Blowing in the tube is forcing fuel into the system, making it richer, and then it starts. Those choke circuits need to be opened.

Of course, good voltage at the coils is also important.

[TheBigRed]

I agree with Sandy. Blowing in the tube is forcing fuel into the system, making it richer, and then it starts. Those choke circuits need to be opened.

Of course, good voltage at the coils is also important.

I'll third this vote as well.

My 650 was this way for a LONG time, and I just dealt with it. Then I got re-build kits and dropped them in my 550's carbs and put those carbs in the 650, problem went away.. When I did get around to cleaning the 650 carbs the choke circuit was completely blocked on at least two of the carbs. Some guitar string and some gentle prodding/cleaning fixed them right up.

Amos

I also think you've spoiled yourself some by not using choke in the warm months, the bike doesn't need it as much then. But now that it's colder (as you stated) pulling the choke all the way out makes use of the choke circuitry and you've been getting it to start without blowing.

[TheBigRed]

my girl is an '82 gs650 with a similar problem. where do i blow to get her going in the morning?

You should have vent tubes coming from between carbs one & two, and another between three & four. When I was doing this I used the one that came from between one & two, and it was enough to get the bike to start.

As I stated in my last post though this is a symptom of the choke circuit being blocked, time to tear down those carbs and do a good cleaning (btw, soaking alone isn't enough, though it loosens the crap) Thorough cleaning, paying special attention to the choke circuit running into the carb bowls. I kept at it until putting water into the channel at the top would flow (though slowly) out the small orifice in the bottom of the bowl.

Amos

[Zooks]

Blowing me usually puts me to sleep.