Lean Resolution?

[jrm03]

I did a plug check and I have a slightly lean condition. The side electrode is white and the porcelain is white with just a touch of brown which tells me I am close on the jetting. I'm also running 110 leaded Torco. Would it be possible to richen my mixture enough with the use of a little more restrictive Uni filter. I currently have a K&N. Is the colder air also causing a lean condition? I don't know alot about the 450 carb that I have on it, so I don't want to tear into it if I don't have to. Thanks

[underpowered]

colder air is more dense than warm air, so you are gettin more oxygen in your motor probably causing you lean condition. i usually just put my airbox lid back on for winter riding. not exact but gets me close enough.

[jrm03]

I plugged up the holes in my airbox lid. I was wondering if something like a UNI or other foam filter would richen me up enough to get by.
Thanks for that info. I am close but I want to be a bit on the fat side which should leave me sitting pretty good when the warm weather comes around.

[GPracer2500]

Originally posted by jrm03
....I want to be a bit on the fat side which should leave me sitting pretty good when the warm weather comes around.

If it's fat when it's cool then warm weather will make it even fatter.

[jrm03]

Any suggestions GP? This stroker has an insane amount of torque and power so a lil loss won't be a big deal. What kind of comparisons does anybody know of on the flow of filters.
Is it even reasonable to think that changing air filters may richen me up enough instead of changing the jetting?

[jrm03]

I forgot to ask, how does runnin the 110 leaded change how you diagnose jetting?

[jrm03]

Anybody?

[Eviltanker]

No it shouldn't,just i think if thats the fuel you are going to use to jet it then thats the fuel you should run in it afterwards.
Just my.02

[GPracer2500]

Different filters can make a difference. Even the amount of filter oil in/on them can make a difference. But it's usually a small difference--one main jet size, perhaps two at the most? I'm half guessing and half basing those comments on the experiences I've had with swapping a K&N back to back with a UNI. I didn't do any hardcore testing--just happened to do that swap once.

Running a racing fuel won't change how you diagnose jetting except for reading plugs. Different fuels might color differently. One thing a high octane leaded fuel can sometimes allow is pushing the limits of leaness in the quest for maximim HP. Lean mixtures are more prone to deto so if you're fuel offers lots of deto protection then you can play on the edge with a larger margin of safety. Although high octane fuels don't in and of themselves create more power, they can allow for more aggressive tuning.

If you're looking to "rejet" without actually changing any jets then I prefer using a vented airbox lid (similar to what underpowered suggested). Tape up some/all of the holes when the air is dense and remove the tape when the air is thin. By gradually opening up the venting you can control a/f mix pretty well. This works well on long rides that start at 1000ft and end at 8,000ft. Leave taped up and end opened up.

[jrm03]

Thanks for the words fellas. My intentions are to put on a UNI filter and a closed airbox lid to richen it, then go to the setup I am currently running with the K&N and vented lid when the weather warms up. Thanks