Dodgy earth/ground connection from fuel tank?

[Guest]

Hi there, My bike will only rev in gear when I lift the fuel tank up so the top of it touches the stem. I can only assume that this is earthing it and wondered if there's a simple way to create a new earth/ground connection rather than try to find the fault in the original one. There's a green and a yellow wire coming from my fuel tank (One of which is insulated from the tank, the other meets a cooper plate on the tank itself) into the loom which goes to the headlight connector boxes, it's a maze of cables from there and I just want to know where I could try and earth my tank to so it's safe...

Does this make any sense? Regards

[Grumpy Old Git]

Any clean metal on the frame or, the battery earth point.

[eastanglianbiker]

fuel tank is normally rubber mounted to insulate it from the bike apart from having fuel gauge fitted which will have its own earth,it sounds more like a wiring or cable problem to me whch is being allowed to move when tank is lifted

[Chrissb6]

Hi sound very much to me that your fuel tank is trapping some point of the wiring loom and creating a short. Have a look for any pinch points underneath the fuel tank that might be causing the problem. The only wires coming out of the fuel tank should be the fuel gauge sender unless you have a fuel injected bike? Then there could be a fuel pump inside. Again check all connections and make sure nothing is getting trapped.

[Tango]

My tank is plastic.....

Agree with the guys.....sounds like the tank is trapping or pulling some wiring somewhere.....possibly even shorting some wiring.....tank off and a good look round required I think.....

[Guest]

Thankyou all for your collectively correct replies, it was indeed a cable fault under the seat, (despite repeated fumbling to try and eliminate this possibility) one of the connecter boxes was damaged, I'd dropped the bike on my drive having had a brutally debilitating fever and that must've stressed it.

I got lucky in being able to diagnose as far as the earthing problem (got it to work by taping tin foil between the tank and stem) but that also kinda threw me away from the source of the problem.

However, by running it with the tank off, I noticed one of the connecters was HOT! Fixed it with an electricians chocolate box connecter. Such a strange problem! Sometimes it seemed like it would work until I got all geared up to go and sat on it, Utterly bizarre, but back on the beautiful sussex roads.

Cheers all

Oh Yeah, so I guess there's a reason why the tank is rubber insulated form the metal frame!

[Chrissb6]

Thankyou all for your collectively correct replies, it was indeed a cable fault under the seat, (despite repeated fumbling to try and eliminate this possibility) one of the connecter boxes was damaged, I'd dropped the bike on my drive having had a brutally debilitating fever and that must've stressed it.

I got lucky in being able to diagnose as far as the earthing problem (got it to work by taping tin foil between the tank and stem) but that also kinda threw me away from the source of the problem.

However, by running it with the tank off, I noticed one of the connecters was HOT! Fixed it with an electricians chocolate box connecter. Such a strange problem! Sometimes it seemed like it would work until I got all geared up to go and sat on it, Utterly bizarre, but back on the beautiful sussex roads.

Cheers all

Oh Yeah, so I guess there's a reason why the tank is rubber insulated form the metal frame!

Glad you found it, that chocolate block connecter is not really suitable for the task in hand, better to source a proper auto - water oil proof connector for the long term. Rubber mounts on the fuel tank are to isolate it from the vibration from the motor.