250cc dies after filling up tank. By carmelotrump (Read 795 times)

[carmelotrump]

Does anyone know why that after I fill the gas tank my bike just shuts down, wont even start, I have to get a jump & then when I get it started only one headlight comes on until I fully charge it on my tender.

[silas]

Did this just happen once, or several times?

It's an electrical issue of some sort. If this happened many times, then maybe it is related to the fuel tank float sensor. In that case, I would suggest disconnecting the wire harness from the sensor and check then.

If it only happened once, then you might want to get a schematic and do some general troubleshooting measures to isolate the problem. That, or try to narrow it down if it becomes a pattern of symptoms. I'd rather find the problem with a schematic and a multimeter before it happened again, which could possibly damage some components.

Silas

[carmelotrump]

Thanx for the reply Silas. it has happened every single time I gas up since I bought the bike. Far as me doing all that other stuff I dont know jack didly about that stuff, but I will find someone who does & let them do it..

[Alleyoop]

One thing that might be happening is if the tank has a EVAPPRATIVE system and you OVERFILL the tank Gas goes into the VENT HOSE and CLOGS the EVAP CANISTER. And if it is clogged the Tank will NOT VENT and not allow fuel to flow to your Carb. So next time do NOT fill it to the top and see if that helps.
Alleyoop

[silas]

Alleyoop,

It's not exactly explained 100% but the fact that his headlights won't work properly, and that it has to be jumped off makes it seem like electrical. I wonder...

What kind of scoot is this? Alleyoop would probably know which models would be prone to the fuel vent problems.

Silas

[Alleyoop]

It sure sounds like the sensor is drawing a lot of juice or grounding out or something when the float moves all the way up on the Resistor plate. But maybe when he overfills it gas is going into the vent hose and not allowing the fuel to flow and IF he is cranking it and drawing the battery down then he has to jump it to start it.

But it is easy enough to unplug the sensor from the float sensor and that would tell all if the sensor is the culprit.

CARMEL,
it is easy to unplug the Float Sensor from the harness. Just follow the wires from the FLOAT Sensor on the tank and UNPLUG it and see if it starts. What I would do is get some gas and fill it at home and before you try to start it UNPLUG The Float all that is going to do is your gauge will not registor and you will know right away if that is what is causeing the no start.
Alleyoop

[Bashan]

I think these guys are onto something here. Most of these gauges work like this now using two coils:

Here's the variable resistors and the float arm:

It's feasible that part of the resistors would work OK but part could be shorted. It would ground the system and drain the battery when the short is touched. I still can't figure out why just one headlight would quit working though. Rich

[carmelotrump]

Thanks again guys !! it's a 2008 shanghai schenke 250cc. I'm going to try next time it gets low to fill up using the gas can & see if that happens. I was thinking maybe there is a loose wire and when the metal from the pump touches the tank mouth it shorts out. even when I get a jump it'll run until I turn it off, then it's doing the same thing until I fully charge on tender, Now once I charge it fully it cranks right up both lights blazing until I gas up again.