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Old December 26th, 2020, 09:42 PM   #2
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
You changed too many things at once. Something went wrong, but it's impossible to say what that is since it could be more than one thing. Restore your bike back to 100% bone-stock and verify it works 100% like stock. Most likely it will not, as something got tweaked. Fix whatever that is, wiring, vaccumn-leaks, carb-refurb (not just cleaning), etc.

Once bike is running like off showroom-floor in 100% bone-stock config, do only ONE upgrade at time and fine-tune on dyno to verify proper AFR before moving to next upgrade. Do in this order:

1. Kleen-air and EVAP removal first as it doesn't affect intake air-flow or AFR. Verify bike runs just like stock after this step. There's A LOT of vacuum-hoses that must be removed or capped-off to ensure proper carb operation. If not done properly, bike will run like sh*t at this stage.

2. snorkel remove and K&N filter. Bike should feel slightly crisper than stock now.

3. jet-kit, use clip #2 position (one down from top), DJ #96 mains, leave mixture-screws @ 2.5-turns out. Low-end flow is same as stock, no need to change anything. Do 5 dyno-runs, toss out highest & lowest. average rest and draw plot with AFR. Post that chart here for review. Might need to adjust needle or mains before progressing to next upgrade.

4. Area-P full exhaust last. Do more dyno-runs and analyse AFR after each one, adjust as necessary. Most likely AFR will be in super-rich 10:1 range. Target 13.5:1 AFR under WOT in high-end for max-power. Might want to aim for 12.5-13.0:1 for more safety in case of bad petrol, or super-hot day. Won't sacrifice too much power, but gain A LOT in safety.

I started out with this exact list of mods from stock on my race-bike. Except with Tyga exhaust for +1.5bhp over Area-P. My sponsor Spears spent 1/2-day doing at least 20 dyno-runs and pulled carbs several times to downsize mains to dial it in.


You want to be extremely careful when doing mods like this, because risks of destroying engine are great. Very first step is to verify bike is running perfectly in 100% bone-stock condition with fully-refurbed carbs. A lot of people use jet-kits as way to avoid carb-restoration to factory-fresh clean condition, but that never ends well. I tried that trick 25-years ago with my 1st bike and unbeknownst to me, one of carbs had dirty clogged fuel-circuit. I just threw in exhaust and jets and ended up with this:




Now I'm fastidious about checking AFR. I use TechEdge fully-digital wideband O2-sensor with on-board datalogging to verify my AFRs are spot-on after every mod. Also to verify dyno-calibrations, I don't trust many of them.

Last futzed with by DannoXYZ; December 26th, 2020 at 11:42 PM.
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