The CB1100 Community Forum

You mention dark brown and shiny.

I wonder if you are burning oil.

Might want to do compression and leak down tests.

(01-01-2021, 02:58 AM)PowerDubs_imp Wrote: [ -> ]You mention dark brown and shiny.

I wonder if you are burning oil.

Might want to do compression and leak down tests.

(+1) My thoughts as well.

I live by one rule over all.... KISS Keep It Simple Stupid. So many times I have been burned by this simple saying.

You have been given a lot of good info.
1. Test for Spark. To verify the Spark Plug Boot is good and it has spark for that cylinder.
2. If not... Replace the Spark Plug. Try again for spark.
3. If you have spark move on to a Compression Test on that Cylinder. If this fails you have a large problem. I still feel that the Spark Plug, Boot or possibly a chafed lead is your issue. Could also be a simple as a loose connection with the repairs you have done?

I hope you figure this out.

(01-01-2021, 02:22 AM)frank_imp Wrote: [ -> ]Good to know LR, is your bike stock? I was talking about riding from Golden to Boulder on highway 93. There are a few longer hills, and no way would my bike go over 80mph. I'm hoping it's the plug. I'll check into it after it warms up today.

Frank, 100% stock, but I no longer have the bike. I can’t believe you’d have any trouble on 93 — that stretch of road is what, 6000 feet elevation? Maybe 6500 max?

I couldn't agree more teamvisegrip! The plug doesn't look like oil burn, but rich. I swapped the outer most cylinder plugs with each other. The gaps were good. I'm going to check the exhaust temps with an IR gun and then ride it around today once the temps warm up.
LR, I agree that the road I was riding wasn't that steep or high and was surprised by the lack of high end power which led me to think this bike was strangled for air and fuel. If the suspect cylinder is still running rich, I'll check the spark and drop a scope in the cylinder. I'm assuming a typical plug check won't cause harm, meaning ground the plug to the cylinder and hit the starter which will cause the bike to probably run on 3 cylinders for the test and look for a good blue spark? I don't want to smoke anything electrical running this test. Thanks again for everyone's comments!

An alternate suggestion. Go out to a deserted road, and get on the throttle a bit. Then turnaround, go back to the starting point. Stop, reach down and pull the suspect plug wire off, and do the run again. If no noticeable difference in speed or acceleration, then you've confirmed either a bad plug or bad plug wire.

Teamvisegrip, I KISS and it was a bad plug. I checked the pipe temperatures and the cylinder that I moved the bad plug to was now not heating up. Went to Honda and paid $23 for 1 plug, need to find a cheaper source, but the bike is running fantastic!!! What a difference. A little background, I never rode a CB1100, found a mint one with only 2300 miles, rode it and it felt choked down, so I thought. Meanwhile it was only running on 3 cylinders. It ran smoothly, just lacked top end power. I wonder why it didn't throw a check engine code or something? Now my new question is what, if any, damage to what could have occurred running it on 3 for ~700 miles? Mostly highway and I did run it kinda hard and up to 80 mph a few times It's running great now, especially with the mods. The 14" Delkevic sounds awesome by the way for anyone looking. I do have a problem with the centerstand rest on the pipe causing it to spin the pipe and then the centerstand rubs on the chain. I tried to tighten the bracket to the max and it's still spinning. Could I put some high temp RTV and kinda glue it? Any tips would be most helpful!! This joint has one of those carbon sleeves and it makes it a somewhat slick surface and probably why it's spinning. Anyways, thanks to all and be sure to KISS!

I am very happy that is was just a bad plug ! ( see post # 8)
For all those years I have been trying to tell you guys that I am ALWAYS right , this proves it once again. For the naysayers about me not being right you must have talked to my wife as after 46 year she still does not get it about me being right all the time.......

(01-02-2021, 10:22 AM)Houtman_imp Wrote: [ -> ]I am very happy that is was just a bad plug ! ( see post # 8)
For all those years I have been trying to tell you guys that I am ALWAYS right , this proves it once again. For the naysayers about me not being right you must have talked to my wife as after 46 year she still does not get it about me being right all the time.......

Possible damage... I would not worry about it too much.

But... there is always a but... if you did run the bike for 700 miles with a dead cylinder I would definitely change the oil. The unburnt fuel may have polluted the oil. Just change it and the filter to be safe.

So glad it was something simple. No go enjoy that wonderful machine.