busakiller
Registered
So I swapped plugs in my bike from cr9e to a cr10e and it started to run lean. It’s at less 1 point leaner then it normally was with the old plugs. Is that normal?
Cr9e to cr10e spark plug change tune?
- Thread starter busakiller
- Start date
With NGK's the number corresponds to the heat range.I believe lower numbers mean they are hotter.So your prob doesn't make sense to me going to a 10 is a colder plug. I THINK. How did you arrive at the diagnosis,that its one point leaner?
Rubb.
Rubb.
I'm also not sure that changing plugs could contribute to making a motor run more lean. Changing plugs does not alter the F/A mixture,but it could contribute to how the mixture is burned.
I'm totally looking forward to getting schooled on this from someone with higher intelligence on the topic than me.
Rubb.
busakiller
Registered
I have a wide band sensor and it’s showing that’s it’s running leaner then it did before last year. It’s not just at idle either it’s at like all rpms. The fuel pump and injectors are only 2 years old and maybe have used 40 gallons of fuel. I’m going to put a new set of Cr9e plugs in today and see if anything changes. If nothing changes I’m going to get the injectors cleaned and look at the fuel pump.
So you are positive it started to run leaner the second you changed the plugs...I think coincidence myself.
Rubb.
busakiller
Registered
Going to a colder plug for the large nitrous shot I would like to run.
it had fuel from last fall. But now it has fresh gas in it and it’s still lean.
Have you recently changed air filters,exhaust,etc or flashed or new PC map?
Rubb.
busakiller
Registered
Only thing that has changed is I took the head off over winter to remove a broken spark plug.
busakiller
Registered
I pulled the plugs to make sure it wasn’t the wideband.
busakiller
Registered
Update on this. I had my injectors cleaned and they came back fine. The guy that cleaned said that they were a little dirty. But nothing that would effect the tune. I also changed the spark plugs to the oem heat range and put fresh c16 in the bike. Bike runs fine now. I’m going have to say the old c16 was bad or I had a bad plug. I’m going to buy a new set of colder plugs and try this one more time.
I'd keep the plugs at stock range...if it's running fine, don't mess with it IMO...
busakiller
Registered
changing plug heat cause I have nitrous on the bike. Right now I’m spraying about 85 90 hp on it. I plan on nearly doubling that. So it’s probably a good idea to change plugs to a cold heat.
...Right, forgot about that...
202mphbusa
Registered
ONLY way it could read leaner now with colder plugs is if now you are getting NONE firing intermittently
that reads lean not rich
that reads lean not rich
busakiller
Registered
Ding ding ding. I was talking to someone yesterday and he said I could of fouled a plug. He said colder plugs do foul easier. Makes total sense now. I put colder plugs in after I put the head back on the motor. I could of fouled the plug on 1st start up.
busakiller
Registered
Update. I bought brand new plugs and gapped them .022. Bike started right up and idles fine and revs nice. Afr looks to be that same as before. My guess is I fouled a spark plug or had a bad plug when I first put the motor back together from repairing spark plug threads.
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