1 cylinder running rich?

[frank_imp]

So I have the left outer cylinder, if sitting on the bike, running rich. I just installed a full Delkevic exhaust, stock air filter, PCV with the yoshi map. At first I ran the stock map and didn't have the O2 sensor installed and went for a quick ride. Obviously the check engine light was on, but the bike ran better than stock. After returning, I noticed 3 of the 4 headers had changed to the bronze color, but the one was still silver and new looking. I pulled the plug and it was dark brown and shiny, the others a nice light tan. I next put the O2 sensor in and went for a ride. On the highway, the lower end felt fat or blah, but the top end was much better and was able to pull 90mph with relative ease. The stock bike could hardly hit 80mph. I live at 5300'. After returning, the one pipe was still silver showing it was still running rich. I then loaded the yoshi map and it made the lower end much better and very responsive, but the upper end was back to blah. The 2 maps are very different and the yoshi one takes fuel away which is the opposite of what I'd expect? Dynojet is of little help other than trying to sell an auto tune. Anyways, sorry for the winded story, but does anyone know why one cylinder would be running rich? Could the power commander cause this or is the fuel injector need replaced? Could running without the O2 sensor have caused a single cylinder to run rich as a default kinda thing? Thanks for any and all help!

[dave]

I can't answer your question, but your bike in stock condition could barely go 80 mph? Was this up a steep incline?

[noroomtomove]

I'm interested in how this works out.

Regards NRTM

[GoldOxide_imp]

Is it common for bikes like the CB1100 to not easily do the ton at 5300 feet attitude?

[Cormanus]

My recollection is that members at altitude have previously talked about how well the CB1100 performs.

[teamvisegrip_imp]

If I may add my thoughts on this one...

3 of your 4 pipes are hot and discolored. Your Left Cylinder is not discolored or hot. Hondas are amazing bikes and rarely fail. But the non-Honda items might. My suggestion is to replace that spark plug or check the boot to be sure that there is a good connection. Sounds like there is no spark or limited spark in that cylinder.

Good luck.

[frank_imp]

Thanks for the responses! I was going up a hill, not super steep but sustained. The top end in Colorado is lacking and the main reason I wanted to open this bike up. I was planning on swapping plug 1 with 4 and seeing if the color remains. I'm assuming your thoughts are the injectors are delivering equally and the power commander delivers to all cylinders/injectors equally as well? I'd love it to be the simplest and maybe the reason the bike seemed like a dog in stock form. The bike has always idled and sounded smooth, never ran or sounded like it was missing. I pulled the opposite outer plug before I did the mods to see how it was running, so I don't know if the rich cylinder has always been rich or only after adding the pipe/PCV. Thanks again for all responses and I'll report back what I find with the plug swap.

[Houtman_imp]

It could be as simple as a "bad " plug , in a recent F1 race one car had a problem with plugs. On one of my CBX's I had a problem as the bike run on 5 cylinders , new plug in one of the outer cylinder cured the problem . It is a cheap "first repair "

[LongRanger_imp]

I don’t think it’s the altitude. I rarely ran that hard, but my ‘14 would hold 90-100 mph on uphill stretches at altitude (Copper Mountain to Leadville via Fremont Pass, for example, which is 11,300 feet).

[frank_imp]

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.