05 Boulevard C90T runs rich

Dr. Mike

New member
Have had this bike for about 1 1/2 yr. ran good at first for about 6 months,untill winter. Then plugs fouled, black carbon. Replaced plugs, ran good for about a month. Now they are fouling in about a week. Im thinking block temp or air temp sensors. Any help here would be great. before I bought it it had after market pips installed and was told it was dino tuned.
 
The C90 runs lean from the factory and if you have a.m. pipes installed will run even more lean. You cannot, AFAIK, change the factory settings so the dyno would be worthless unless you have a fuel processor installed as well, PCIII, Cobra FI2000r, or a Bully. Maybe you have a fuel processor and just are not aware of it??

BTW, fill out your profile so we know a bit more about you.
 
When it starts to run bad I pull the plugs and they are carbon fouled, so it's not running lean but rich. May be I should put a K/N filter on it as they tend to make it run lean. How ever I would rather get to the real problem and fix it right. Does any one know if you can pull codes with a car scanner, I have a snap on MODIS. (I'm an Auto tech) Were it the diagnostic plug on a C90T. Yes the check engine light is on.
 
I am not that familiar with the electronics on the C90 so I do not know how to get the codes, but if it was running right before then it is not the air-fuel mixture settings or the pipes. Clogged air filters can make it run rich, as can a bad or dirty O2 sensor, or a bad coolant sensor (ECT) making the ECM think the bike is cold so it goes into a closed loop and richens the mixture trying to warm it up. The intake air temperature sensor (IAT) could cause a problem with the mixture also, but I usually find the IAT leans it out when defective.
 
I know the difference between rich and lean but what I was trying to get at was you mentioned the bike was put on a dyno. You cannot adjust the factory ECM. There would have to be an a.m. fuel processor to adjust for a proper dyno. Yes, putting in a K&N filter would lean it out but maybe too much. I would say first look and see if you do have an a.m. fuel processor, identify the make of it, PCIII, Cobra Fi200r, Bully. What Dr. Bob mentioned are possibilities as well but a fuel processor would be my first guess. I have a Bully fuel processor on my '07, HK sideburner pipes and wide open K&N filter. I can adjust my setting on the fly to the point of rich or lean the bike either won't run or will burn up.

The diagnostic plug is under the left faux cover near the neck.

Got more questions then go to the best forum for the C90. Click >HERE
 
Vinnie is saying what I think as well. If you can skin the bike down and remove the air cleaner assembley, you will see the carb injectors. Trace the wiring plugs, and I'll bet there is a Power Commander brand injector controller in-line. That would be the only reason to have done a dynomometer tuning. While you are in there, note (or take a picture) of your air filter. Take two beers and call us in the morning.
 
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