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DannoXYZ · February 7th, 2020, 04:24 AM

There is ABSOLUTELY ZERO way any mechanic can tune carbs optimally by ear! This has been proven thousands of times after putting their "tuned carbs" bike on dyno and actually measuring power-output and AFR... way, way off.

Sorry I made typo. "Dyno tuning" is running bike on rollers and using exhaust-analyzer to determine AFR-air fuel ratio. Then changing carb adjustments to get AFR into most-power producing range.

https://www.ninjette.org/forums/showthread.php?t=63914
https://www.youtube.com/watch?v=W7G0UWdsrA4
https://www.youtube.com/watch?v=rL4Gmt_r0cA

Typically on new-gens at least, LOTS of power is added with full-exhaust and removing fuel by going to smaller main-jets. I've seen up to +22% more power just from fine-tuning AFR, which is about twice as much as initial gain from just slapping parts on. On my bike, Spears downsized the main-jets twice after reviewing dyno's AFR data. On 300s, about +14% more power can be gained just from leaning out AFR with no parts changed or added. This is done on dyno again, with re-programming ECU instead of mucking with carbs. Part of better response from 300 is due to 3D ignition-maps compared to 250s 2D map.

Factory foam filter works fine. Problem is lots of people over-oil it and cause restriction. A K&N filter is common replacement. Just two light layers of spray-oil per side is all that's needed to sufficiently oil filter. Or you can use spray K&N filter-oil with factory foam filter as well.

February 7th, 2020, 04:24 AM	#28
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	There is ABSOLUTELY ZERO way any mechanic can tune carbs optimally by ear! This has been proven thousands of times after putting their "tuned carbs" bike on dyno and actually measuring power-output and AFR... way, way off. Sorry I made typo. "Dyno tuning" is running bike on rollers and using exhaust-analyzer to determine AFR-air fuel ratio. Then changing carb adjustments to get AFR into most-power producing range. https://www.ninjette.org/forums/showthread.php?t=63914 https://www.youtube.com/watch?v=W7G0UWdsrA4 https://www.youtube.com/watch?v=rL4Gmt_r0cA Typically on new-gens at least, LOTS of power is added with full-exhaust and removing fuel by going to smaller main-jets. I've seen up to +22% more power just from fine-tuning AFR, which is about twice as much as initial gain from just slapping parts on. On my bike, Spears downsized the main-jets twice after reviewing dyno's AFR data. On 300s, about +14% more power can be gained just from leaning out AFR with no parts changed or added. This is done on dyno again, with re-programming ECU instead of mucking with carbs. Part of better response from 300 is due to 3D ignition-maps compared to 250s 2D map. Factory foam filter works fine. Problem is lots of people over-oil it and cause restriction. A K&N filter is common replacement. Just two light layers of spray-oil per side is all that's needed to sufficiently oil filter. Or you can use spray K&N filter-oil with factory foam filter as well.