85 interceptor 700 engine cuts out

I wonder if anyone else out there has had this problem. I can drive all day on my bike when the speed is below 65, but when I take it out on the highway at 70 or above, after about 10 minutes the motor chokes out. If I pull over and wait a minute it will start up and run fine, but if I go back on the highway it does the same thing, and if I just go back roads it runs fine.
Any ideas?

 

Sounds like your starving for fuel at high speeds.

1. Your fuel pump is dying and cannot keep up with demand from the carbs.
2. You have a fuel filter between the pump and the carbs. The pump may receive a false backpressure and cut off.
3. You have a partial vacuum clog on the tank, not allowing enough fuel to flow.

 

Fuel delivery could be the problem. An easy way to check is the find a back road (it appears like you already have those!) and blast around using as much throttle, as much of the time, as possible (safely, of course). After a minute or less you should start to observe the same conditions as your highway speeds. My guess is that it is not the fuel delivery.

I'd also look at heat as a possible cause. If you have a pulse generator going bad heat will push it "over the edge." A short amount of cooling is all that it takes to bring it back. This same thing happened to another guy on here about a year ago. I suggested then, as I do now, to take a voltmeter along with you and check the resistance of the pulse generators as soon as possible after the engine dies. Compare this to the manual spec and you might just find the problem.

Keep us up to date on what you find.

 

There is a fuel filter clipped under the pump. That one eluded me for weeks, and was the cause to so many problems.

 

Thanks for the ideas

Thanks everyone for your replies, I really didn't think anyone else had any more ideas, this is great.

I did replace the fuel filter and the sparkplugs, with no change, on to the other ideas you gave me, I'll keep you posted.

Once again thanks so much.

 

Are you planning to check the pulse generators? I would suggest that as the next step. Considering they are electrical components and where they have to operate I'm surprised they don't fail more often.

Let us know what you find.