Help! My bike won't start!!!

Hey guys, I'm having a problem with my '85 VF500F.

So this morning I got out my bike to take it for the first ride of the year, needless to say I was pretty excited.

Now, two weekends ago, I gave it an oil change and charged up the battery, and it started and ran just fine. But it was too cold to go for a ride.

Anyway, today I took it outside, put the choke on, and it started right up. So I was letting it warm up with the choke on, but after a couple minutes, the rpms got lower and lower until it just died. I tried starting it again and it would run for a second and then just die.

The gas in it was the same gas I had left in over the winer with stabil in it. I thought that was the problem, so I syphoned out all the gas, went to the gas station, got a couple gallons of premium gas, and put that it.

But now it won't start at all! When it died it was acting like it ran out of gas, but there was plenty of gas in the tank and I tried setting the fuel switch to both on and reserve, but nothing happened.

Anyone have any idea what the problem could be?

Thanks a lot!!!

-Chris

 

Does your bike have a fuel pump? maybe that went bad and it isn't getting fuel.

 

Arrrg, I can't even get the fuel line disconnected from the tank cause that ancient rubber tube is fused on there. I'll try again in a little bit and post an update!!!

 

Ok here's the situation now:

My dad got home and helped me disconnect the gas tank. We disconnected it at a joint in the fuel line midway between the tank and the fuel filter.

BUT, when we got it off, there was no fuel in the six inches of fuel line still attached to the tank. This makes me think that no fuel was getting past the fuel shutoof valve. I was able to open and close the valve and no fuel came out of the tank (there's plenty in there).

Should fuel be able to flow through the valve on its own, or does it depend on suction from the fuel pump?

 

Your tank should gravity drain, regardless of whether you have a fuel pump or not. The gas always exits the tank from the lowest point... all the fuel pump does is overcome the "trap" effect caused by having your carbeurator at a higher elevation than the petcock valve. Perhaps something is clogging the fuel line? Try replacing the line. If it's stuck,you could simply cut the thing off with a razorblade and replace it. New fuel hose costs a few bucks at an auto parts store.

Another idea... you might want to pull your petcock valve and check the filter screen. Maybe the screen is clogged? It's pretty easy to do, but it requires an empty tank... you'll have to get creative. If you go up-ending the tank, be carefull not to screw up your stock paint/decals with the gas. I doubt it's a clogged screen though, since this problem came on suddenly.

It's also possible that the rubber seals inside your valve are shot, but I can't imagine that would lead to a perfectly stopped up valve. I'm betting the fuel line is clogged somehow.

 

Ok well pops and I are gonna start examining this petcock device and see if we can find the problem!

I will keep you informed!!!

 

Hm, we took apart the whole shutoff valve and everything seemed to be just fine, except the filter was a little dirty. I washed off the filter and put it back together. Next I'll see if I can get anything to flow out of the tank.

 

Ok update again:

After cleaning up the whole fuel shutoff valve assembly, we put it back on the tank and put in a little bit of gas. Now a little bit of fuel drips out when the switch is on reserve. It seems like barely any is coming out, but then again, I only put a very small amount of gas in.

Also, back on the bike, there were two lines I disconnected when I removed the tank. One went from the fuel shutoff valve, where the gas would come out, to the fuel filter and pump. The other line went from another spot on the shutoff valve to one of the caburetors. Anyway, I put my finers on the ends of these lines and cranked the engine, and I could feel a little suction in both lines. I'm thinking that's good.

I will investigate further tomorrow!

 

I had to rebuild the petcock on mine for a vacuum diaphram leak, even with the switch turned to on, it won't flow unless vacuum is applied.

 

Try compress air being shot up the gas line of the tank. Be careful. But that should clear out any blockage. Also if it drips hook it back up and see if the pump shoots gas out of the other end of the line that goes to the carbs. That should tell you if it is still blocked.

 

AHA!!! I tried what you said, and it worked, so I put everything back together, and the bike runs just fine now!!! I still don't really know what the problem was to begin with, but it works now so I'm happy. Time to go for a ride!

Thanks for the suggestions everybody!

 

Bad gas seems to stick the tank like glue. Glad its working for you now. I would suggest changing/installing a fuel filter too. That way you aren't cleaning the carbs later on.

 

I'd also run some carb cleaner through the next serveral tanks.

 

Yeah, that's what I was thinking too, just to be on the safe side