What's going on? Start problem

[Anonymous]

Hi guys,

I recently bought an 82 GS450S, and it has been running great, until yesterday. I get to my bike, and notice a smell of gasoline, so I check the bike and see a big puddle of gas beneath it.

I didn't really know what to do about it, so I started to search for the source: gas was seeping from the connection between the carburetors and the engine top end. I tried to start it, but all I got was a clicking sound from somewhere near the battery. I started pushing it home, and somewhere along the route I decide to see if it will start again - and it did!

So I limp back home (3 miles), and start researching the forums, and I learn something new: PRI does not mean Primary #-o
At least I now know where the gas came from.

But now the bike won't start The starter is turning, but it won't fire.

Do you have any ideas why it won't start? I'm a bit puzzled that I got it started yesterday, but today it will not start - if the engine was drowned, it should be cleared out after the ride home, right?
And what are the chances gas has entered the oil? And if so, what would the symptoms be?

Thank you for any help

[SqDancerLynn1]

Hard to say if you got gas in the oil but I would change it for saftey
I would clean the spark plugs

[ddaum]

Hard to say if you got gas in the oil but I would change it for safety
I would clean the spark plugs

You said it. This happened to me when I first got my bike (80 GS550L 25K). The PO had the petcock in PRI during storage and slowly drained a whole tank of gas into the crankcase. While unaware of this, I was trying to start it and flooded it bad. I took out the air filter and cleaned it, wiped up the gas in the air box, and removed the plugs because they were fuel soaked. Then I drained the carb float bowls, disconnected the fuel line, and cranked the engine a bit with the plugs out and cleaned them in the process. I also took the oil fill cap off and took a whiff. The crank reeked of gasoline, so I changed the oil & filter with some cheap stuff. After I put her all back together and made sure the petcock was in RUN, she started right up and ran strong. 50 miles later I changed the oil & filter again, but with better oil. Now she runs like a champ.

If you have a problem with the gas leak look at the petcock, and rebuild if necessary. Good luck.

[DaveDanger]

I was going to mention as well that the quick way to check if the fuel drained into the crankcase, is to check the oil level and sniff it. It can damage an engine to run for more than a short period of time on fuel thinned oil. Drain it and change it quick if you even suspect it. I echo the troubleshoot procedue on the petcock. The vacuum operated petcock on these things should have an operators license all its own that every owner should be required to pass a test on before being allowed to ride! There's probably others here that explain it more clearly than I, but I occasionally enjoy wading in over my head... <smile>. Understand that the float needles inside the bowls have to maintain a specific level of fuel under all conditions against the fuel pressure that is gravity fed from the tank. On a standard petcock system, there is absolutely nothing but the needles to keep that gravity-fed fuel pressure contained inside the bowl while the engine is not running. The vacuum petcock is designed to automatically close off a port inside the petcock, when the engine is not running (when there is no vacuum to hold the port open). This assumes that the petcock is in the normal "on" position. If the petcock is rotated to the "pri" (prime) position, the petcock is mechanically hold open 100% of the time. You now have a standard petcock. The reason for this is to allow fuel to flow into float bowls that are possibly dry after a long period of storage or not running. As soon as the engine is running normally, the petcock should be rotated to the normal "on" position. All that is said to say this... if the diaphragm inside the petcok is bad, pinhole, crack, tear, etc. the fuel can drain down into the carbs while it sits. BUT, it can also leak down through the vacuum line into the one carb that the vacuum line is connected to. Even if the float needles are up to the job of holding fuel, the vacuum line connection is beyond the float bowl, and will still allow fuel to flow... both directions. Into the airbox and onto the floor, and also forward into the head and on through the rings and into the crankcase. Check out that petcock by disconnecting the fuel line and vacuum line from the base of the petcock and slipping a pair of temporary (Clear, if possible) tubes onto the nipples. Dangle them down towards the floor into a container. Observe the container over a period of time to see if any fuel is being collected. If so, the petcock is in need of a diaphragm and seal kit.