The Nighthawk’s Engine Stalls at Expressway Speeds; Now it Won’t Start

Honda NighthawkI usually like to write after I’ve fixed something. In this instance, however, I’m genuinely stumped.

On the 5th, I rode my motorcycle from Flint, Michigan down here to Chicagoland. Google Maps generally puts the drive at around four to five hours. It took me ten, though, because I couldn’t go faster than 55mph, due to stalling every time I went faster. That was extremely annoying. Every time I hit 65mph the engine would stall, and I would coast to a stop, being able to start the engine generally as I came to a halt with the clutch in.

Stalling on the expressway would be dangerous, but it would start to lose power about 30 seconds before dying, so I could downshift, get to the right lane close to the shoulder, and prepare myself. I’m thankful that I was able to handle the multitude of stalls without issue.

Regardless, I got the bike to Chicagoland without too much issue. Driving on I-290 at 4am is definitely different than 9am or 5pm. It was smooth riding!

Last Night Things Changed

I had thought that the problem was the air filter, since it was so dirty. My thinking is such:

It’s either fuel, air, or spark. Right??

Obviously I had spark, since it’s running and I put in new spark plugs just for fun anyways.

 

I replaced the air filter yesterday and after work I decided to go on a bit of a test run, pushing it to 65mph or faster just to see if I cured the problem. I hit 75mph and then felt a loss of power. It happened again.

With a clean air filter, I’m left with fuel as the problem. I replaced all of the fuel in the tank before I left, and I didn’t see any rust. It’s not the carbs, or else I’d always have problems, and the problems would especially persist at lower speeds, and I’d need my choke on to keep it running (I’ve been there on the Rebel!).

 

So I’ve googled around left and right, searching for things such as engine stalling at high speed, and motorcycle dying on the expressway. What Google has given me is that I possibly have some gunk in the fuel line, or a problem with the fuel filter or fuel screen, or perhaps the air vent for the tank. I have an inline fuel filter waiting for the bike, though I think the fuel line on this bike is larger than the Rebel. I didn’t look too closely or for too long. The fuel line is a little harder to access on the Nighthawk.

 

The big difference that last night held for me though was that after I got off of the expressway, I stalled going 35mph, and wasn’t able to get it restarted for an hour. I have 140 miles on that tank, but the last tank lasted over 180 miles so I didn’t think that I was low on fuel. I switched it to reserve either way, and let it cool off for a half hour in case I over heated.

Bonus: the truck behind me on Naper Blvd stayed there with their flashers on till I was rolling again!

 

So this morning when I was ready to go to work, I got outside, put on the choke, started the engine, and as soon as I gave it throttle it would die. I have a car as secondary transport now, but it was still quite depressing that I couldn’t ride to work. It’s better to be safe in this instance, though. Tomorrow I plan on taking off the tank and checking the petcock’s fuel screen and my fuel lines, as well as putting that inline fuel filter in place.

2 thoughts on “The Nighthawk’s Engine Stalls at Expressway Speeds; Now it Won’t Start

  1. Kyle

    Did you ever figure out what was causing your bike to stall? I recently purchased a 1986 450 nighthawk and am having a similar issue. Stalling at freeway speeds, then having to wait a few minutes before it would start up again. No problem at all on city streets though.

    • Yep, I got it working after putting a new vacuum line on it. That sounds exactly what you’re dealing with.

      Go to an autoparts store. you’ll spend about $1.50 lol

      I brought in a chunk of the line so I could match it with what they have. I just cut off a half inch and reattached it.

      If I were you, I’d replace all of the vacuum tubing and the fuel lines.

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