94 K1100RS sudden loss of power, sounds like a v twin at full throttle

[Motodude12345]

Hey everyone! So a couple of weeks ago I was riding my 1994 K1100RS and it started to feel a bit laggy when hitting the the throttle. Rode a couple minutes back home and at that point it wouldn’t get up in the rpm’s and hardly had any power anymore. Struggled to get it to 55mph. So I replaced the intake boots and o rings where the intakes bolt to the engine, as well as the injector o rings, thinking maybe an air leak. Sanded and cleaned grounds, blew air through the fuel lines, replaced fuel filter and lines in tank. Tested fuel pump and it still has tons of pressure, and new spark plugs.  Yet still, the delayed throttle response off idle, and at full throttle it almost sounds as if it’s running on 2 cylinders? Thinking at this point it could be a spark issue? Hoping to get you guys’ thoughts before dumping anymore money into this thing. Thank you very much!

[Laitch]

Exactly how many psi are you indicating equal "tons of pressure?" Are the spark plugs wet or dry after running so poorly?

[Motodude12345]

Exactly how many psi are you indicating equal "tons of pressure?" Are the spark plugs wet or dry after running so poorly?

I don’t have a way of measuring the exact psi unfortunately. I turned the key, with the hose that goes through the regulator disconnected from the tank, and it was pushing it through the regulator good. With the pump line disconnected from the fuel rail, it’s blasting fuel pretty aggressively so I just figured it was fine. Could be something I could try replacing in the future though? The plugs look dry. One maybe looks ever so slightly damp? Here is a pic of them. No doubt it looks rich. I also should add two things, it idles perfectly. But as soon as throttle is applied, that is when the issue starts. As well as it is somewhat modified with pod filters instead of the air box because it was shot. I also put all new vacuum caps on everything. It ran like a dream with the pod filters for a couple hundred miles though so I don’t believe that they would be the cause of this particular issue.

[Laitch]

Correct fuel pressure to the injectors is unlikely to be determined accurately by sight. You could be over-fueling. While the engine is running, verify that there is a steady—not pressurized—stream of fuel returning to the tank fuel from the outlet mounted at the ceiling of the tank interior above the vapor collector. You can check pressure governed by the fuel pressure regulator by using gauges loaned at NAPA, Autozone or PepBoys generally at no charge simply by leaving a security deposit backed by a credit card. Call around. Here are the instructions from Bert Vogel's troubleshooting guide.

[Laitch]

Did your new spark plugs have terminal nuts on their input ends? They won't operate reliably if just the screws are coupled to the wires from the coils. Do you have a multimeter and know how to operate it so you can check resistance at the coils?

[Motodude12345]

Correct fuel pressure to the injectors is unlikely to be determined accurately by sight. You could be over-fueling. While the engine is running, verify that there is a steady—not pressurized—stream of fuel returning to the tank fuel from the outlet mounted at the ceiling of the tank interior above the vapor collector. You can check pressure governed by the fuel pressure regulator by using gauges loaned at NAPA, Autozone or PepBoys generally at no charge simply by leaving a security deposit backed by a credit card. Call around. Here are the instructions from Bert Vogel's troubleshooting guide.

Okay! Will do. So just looks like a t fitting inserted before the regulator? Will give it a shot. Thanks a bunch Laitch! Much appreciated.

[Motodude12345]

Did your new spark plugs have terminal nuts on their input ends? They won't operate reliably if just the screws are coupled to the wires from the coils. Do you have a multimeter and know how to operate it so you can check resistance at the coils?

Yes and I made sure to confirm they were snug since I had them rattle loose on other machines in the past. I do have one. Do you by chance know what it should read? I’ll look around to see if I can find it as well. I’m sure there’s a post about it somewhere.

[Laitch]

Don't rely on random Web trolls for information.  Download the K1100 workshop manual at this link. Each section of engine systems has a summary of specs. Here's the relevant one.

[Motodude12345]

Haha noted. I’ve been looking all over for one of these! Thank you. Won’t load for some reason but I’ll keep tryin.

[Motodude12345]

Did your new spark plugs have terminal nuts on their input ends? They won't operate reliably if just the screws are coupled to the wires from the coils. Do you have a multimeter and know how to operate it so you can check resistance at the coils?

So I checked the resistance on the coils and I got a reading of 1.3 on both coils at the primary side. Just a disclaimer I have no clue what I’m doing, but does that sound right? Thanks.

[Laitch]

Just a disclaimer I have no clue what I’m doing . . .

What does that mean—you can't follow instructions for finding these values, you won't follow instructions for finding them, or you have no instructions to follow regarding finding them? How did you manage to find them?

How are you trying to download the manual; into which device are you trying to download it; what happens when you try to download it? The attached table shows what you'll find when you download it.

[Motodude12345]

What does that mean—you can't follow instructions for finding these values, you won't follow instructions for finding them, or you have no instructions to follow regarding finding them? How did you manage to find them?

How are you trying to download the manual; into which device are you trying to download it; what happens when you try to download it? The attached table shows what you'll find when you download it.

I’m sorry I didn’t mean to come off as lazy or annoying. I’ve tried to download the manual all different kinds of ways (phone, computer, different browsers etc.)  and it won’t bring up the site. Just a blank white page that I can’t get to load no matter what I do.  I’ve scoured everywhere and can’t find any other manuals that give a spec for the coils. Thank you for the screenshot. I greatly appreciate the advice you’ve given me, but that disrespect didn’t feel warranted. I was excited to try out a forum but I guess I’ll avoid them in the future. Or at least this one.

[Laitch]

❄️