1984 Vf500f

I was riding my bike down the freeway doing around 75-80 at 8k on the tach then suddenly it dropped down to ~6k and got stuck. After that I knew it was gonna start dying again since it died on me once before on the freeway in similar conditions. The engine was still running when it was dying, but the RPMs would slowly drop until the engine just cut off. I'm not sure what's wrong. I left my bike on the side of the freeway to pick it up w/a truck and when I got back to it I could start it again after a few tries. I tried riding it home while being followed by the truck on side streets to make sure I got home alright then it did the same thing but at slower speeds. It seemed like the more I would accelerate the faster it would die. I ended up loading it on the truck and bringing it home. Any input or suggestions would be greatly appreciated! I'm not sure where to begin.

 

you should check thre following: is it getting fuel? is the fuel pump working correctly. how do the coils feel are they overheated bend in the fuel line. plugged fuel filter

 

I already replaced the fuel filter as maintenance. I was thinking the fuel pump, also. I'm going to check it for constant pressure tomorrow with a pressure gauge. There's no bends in the fuel lines, either, and I'll check the coils. Thanks for the suggestions!

 

Your '84 has a vacuum actuated fuel switch. Meaning that even you have your fuel petcock set to On or Reserve and there's no vacuum, fuel doesn't flow. If it's only partially allowing fuel to flow and you're cruising around at highway speeds, you may be starving for fuel. This typically means that you have a vacuum leak or that the diaphragm in your petcock is going bad.

There's a workaround to fix it - you have to pull apart your fuel switch and cut out the rubber diaphragm that cuts off the fuel when the engine isn't running.

Jamie Daugherty has a good write up on how to fix it on his website: Daugherty Motorsports Homepage - V4 Honda Performance Modification Home!

See How To | VF500F Tank Valve Modification

Props to Jamie for his infinite knowledge of the early Interceptors!

 

ddeford, thanks for the link! I'm 90% sure that's my problem and I just did the fix today. All I need to do is seal the vacuum line, I just need to get some washers tomorrow and I'll see how it does. Hopefully this fixes it tho. Thanks again!