Changed Sparkplugs now awful gas mileage

elmostro

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i reacently change my spark plugs sync my t-bodies oil changed and now my gas mileage is just bad. i replaced the CR9E with CR8E is that causing the bad gas mileage?
 
here is the pic
IMGP0787.jpg
 
What year is your bike...how many miles on it and list ALL of your mods :rulez:
 
2003
hindle full sys
pcr
ign mod
multi hub
k&N filter
small air box mod
pair removed
14,500 miles
 
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the service manual
ii.jpg


2 plugs looked wet dark the 2 to the left are cyl 1 and cyl 2 and so on. cyl 3 and 4 were kind of wet. but not 2 bad, is like those 2 cyl are running bit rich.
mm.jpg
 
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Good question BA. I personally see no need to run a cr8 (hotter) for any reason. I've seen cr10's (colder) for bikes running ARC-2's or some type of ignition upgrade, but never 8's.

Pull the 8"s, put in some new 9's and run the bike for about 50 or so miles and then re-check the plugs to made sure your t-body sync is right. From the pic of the plugs, your t-bodies are way off, especially #2 to #4.IMO:thumbsup:
 
to sync the t-bodies i used the jinkster inst and the morgan carbtune tool, everything went smooth.
 
Cyl 1 and 2 look good. 3 is a bit rich and 4 is too rich (still looks wet).
I would look at the map in the Power Commander (pcr) and see what it is doing.
Do you have the individual cylinders mapped or a straight map across all 4?
The next thing could be to have the injectors serviced and that may fix the bad mileage.
What mileage were you getting before and what now?
 
You should be getting twice that much.
I didn't think that plug type would affect mileage, but if that and a throttle sync is all you did.
You could also get the right heat range of plug, and try and swap out the ones that are in there now.
I would try and check the sync again to see if it is still in spec, and check all the hoses are on correctly. If a vacuum hose is off or cracked I think that would cause some loss of mileage.
You must be able to smell gas from the pipe with it running like that.
 
i think i found the problem, vacum hoses not tight enough, i just put zip ties on them and now i'm getting 31 to 32 mpg. do the hotter plugs increase the fuel consumption?
 
i think i found the problem, vacum hoses not tight enough, i just put zip ties on them and now i'm getting 31 to 32 mpg. do the hotter plugs increase the fuel consumption?

Glad you found that part and fixed it.
I am not sure about plug type and mileage.
If all of the gas is not burned properly, it will be put out the tailpipe and you should smell it.
I would guess (guess only mind you) that a plug that was too cold would tend to cause less complete combustion (and less mileage) than one that was too hot.
Anyone?
 
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