Help me resurrect her…’91 k100rs turning over and won’t start

Hey everyone. Thanks for stopping in to give me a hand. I bought a 91k100rs for a couple hundred bucks. Hasn’t run in years and the owner didn’t know why. Fuel pump was bad so I replaced it and the fuel filter. Now when I start it there is a stranger to me noise. You can hear it in the video. The headers are currently off. Would love to know where you would start.

Hello,

I'm not able to get the video to play.

I just uploaded again in case there was something wonky.

mcraffeldt said:

Hey everyone. Thanks for stopping in to give me a hand. I bought a 91k100rs for a couple hundred bucks. Hasn’t run in years and the owner didn’t know why. Fuel pump was bad so I replaced it and the fuel filter. Now when I start it there is a stranger to me noise. You can hear it in the video. The headers are currently off. Would love to know where you would start.

Click to expand...

I was able to make it play by scrolling down, then up. The popping sounds to me like valve action you would not normally hear if the exhaust was in place.

OM

If that’s it then that is great news. Anyone have suggestions as to where they would begin dismissing the inability to start then.

If the bike is an unknown quantity, best to run through all the basics. Start with a valve clearance check, which also gives you an opportunity to check/replace sparkplugs and check plug wires for resistance and continuity. Then I’d pull the injectors one at a time and point into an empty milk jug or other plastic container and see if the injectors are spraying when the bike is cranked. I’m assuming you replaced the fuel filter along with the pump.

Then I’d check for spark when being cranked. If you have compression, spark, and fuel delivery you should at least get a fire or three. The rubber fuel pump mounts on the early K-bikes would dissolve into a gelatinous spooge if left long enough in stale fuel. That spooge can kill a fuel pump or work it’s way into filters and injectors, so if you find any injectors that don’t spray, or spray erratically or with sticking pintles, then a complete cleaning and flushing of the fuel system would be called for. If you do get the bike to run I’d recommend a treatment with BG44 from Napa.

Best,
DeVern

What DeVern said;

Basic automotive troubleshooting: do you have spark at the plugs, are the injectors injecting fuel, are the valves properly adjusted?