1985 VF700 Idle Issue

Hello everyone! I currently bought a 1985 VF700F from a seller on craigslist. Bike is in decent shape and had*the carbs rebuilt last year. I am having an idle and throttle issue with the bike currently. Seems to me that the bike only idles fine when the front brake is applied half way, with choke on. As soon as we let go of the front brake the bike wants to die out and sounds like its sputtering/backfiring. Headlight and tail light start flickering as soon as we let go of the front brake as well.*When we try to ride the bike, the moment we give it gas it seems to bog out and not go any faster than around 5 mph and backfires a lot. But if i hit the front brake a little bit the bike speeds up to around 10 mph. Doesn't seem to go any faster than that. Need help with this issue! Any suggestions? Was thinking maybe it was an air/fuel mixture problem?*Thank you for the help in advance!

PS: We have to jump start the bike and realized previous owner monkey wired the fuel lines..

 

I'd start with a proper carb clean, there's no way the brakes should have anything to do with the carbs. You are going to need to pull them off the bike,remove th floatbowls and jets and make sure they are clean. Lots of carb cleaner, some fine wire and a compressed air supply will be needed.

After that take a close look at the fuel supply from the tank, and the fuel pump.

 

We already took the carbs apart and were spotless, clean as they can be! Previous owner did monkey wire the fuel lines. Found that the metal nipple on the bottom of the fuel tank towards the front of the tank was blocked off/sealed off. Where should that connect to? I'll take a couple of pictures of how they wired the fuel lines, its an absolute mess!

 

When you clean the carbs do you have to sync/adjust them after? Carbs are clean

 

It's electrical! Check the grounds coming from the battery then work your way to the coils. Make sure all ground connections are tight!

 

Having re-read your original post I think Mr Hackaweek is correct about the fault being primarily electrical. Given the bike runs better with the brake lever pulled I'd guess there are chafed wires and/or bad earths that are messing up the circuits.

The power supply for the coils and ignition is routed through the right switchblock where the brake switch is also located, so maybe you need to start in that area, and where the right bar wire harness connects to the main harness.

 

Thanks for the advice! I will definitely check the grounds and see if there are any bad connections, hopefully this resolves the problem. I will keep you guys posted, will check tomorrow afternoon.

 

Battery is too low to supply enough voltage for proper running.

Check the charging system output, and consider replacing the battery.