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Old July 4th, 2022, 01:23 PM   #3
DannoXYZ
ninjette.org certified postwhore
 
Name: AKA JacRyann
Location: Mesa, AZ
Join Date: Dec 2011

Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C

Posts: A lot.
MOTY - 2018, MOTM - Nov '17
Reading plugs is ancient art-form, like reading tea-leaves. It's an average of every single combustion event plug has experienced from 1st installation. So to do it accurately with useable results, you must install new plugs on side of road, do ONE SINGLE WOT run and immediately pull over and chop throttle and shut off engine. Then pull plugs right there on side of road before they cool off.

Modern dyno and wideband O2-sensors give so much more accurate results because they give you instantaneous AFR at exact RPM zones, not averages. This data will tell you that mixtures are both too lean AND too rich. Something impossible to discern from reading tea-leaves.

Your carbs are not factory fresh clean without ultrasonic soak and micro soda-blasting. Factory mixtures way too rich as it is.

My race bike was dyno-tuned with full Tyga exhaust by my sponsor Spears. Very 1st thing he did beforehand was downsize main-jets down to 96. Then we went down one more after dyno runs. Result as +24% more power than stock with smaller mains.

Factory too-rich jetting


Actual top-speed went up from 97-mph to 106-mph on calibrated Vapor digital dash (117-mph on factory dash). Don't forget that all important '60s hot-rod saying...
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