Honda Grom SF & Tuning

Megan Otto & Aaron Schwarz @ Lake City Powersport
Seattle, WA, USA / A 2019 Honda Grom 125cc 4sp Manual
Megan's First Motorcycle / Training for Endorsement

Honda GROM SF // 9.7 HP OEM VIA a 420 Chain From a 4sp Manual Gearbox Connected via Clutch to 124.9cc fuel injected 2 valve single air cooled gasoline powered high fuel efficiency motorcycle powersport vehicle. In stock trim it does about 62 MPH in 4th gear with engine at ~7K RPM, like riding on a weed whacker.

At 229lbs wet, this nimble little Honda Grom is a blast of fun to ride. 4 speeds means less shifting & it does well in Urban City environments 1 up at lower speeds. To take it on the freeway or highway it needs stage performance tuning. Follow along with updates as the tuning takes shape in 2020 :)


Stage 1 Upgrading Achieves mass reduction of 20+ lbs & increases power output to ~11 HP

Fender Eliminator Kit DIY

Zoom Full Loop Exhaust DIY
Listen to it on YouTube // https://youtu.be/E2zUZZp6gp0

Stage 1 parts 1 & 2 done /
 Fender Eliminator w/ Factor Turn Signals & Plate Light
Zoom Full Loop 304 SS Exhaust Pipe

When 304 Stainless Steel heated to higher temperatures, the surface changes color, tints, relative to the heating temperature. On the freeway, throttle pegged wide open, RPM on the border of 8K, searing hot exhaust gasses exiting the heat into the exhaust header heated up the 304SS & gave it a nice progressive tint that will gradually change as I continue heating it over time // take a closer look /

Color formed when stainless steel is heated related to oxidation of the steel such that the heat tint or temper color formed by the progressive thickening of surface oxide layer, so as temperature is increased, the colours changes. Take a look at this table of colors that are likely to form on stainless steel type 1.4301 (AISI 304) heated in air

Color Formed	Degrees Centigrade
pale yellow	290 ( ~554 F )
straw yellow	340 ( ~644 F )
dark yellow	370 ( ~698 F )
brown	390 ( ~734 F )
purple brown	420 ( ~788 F )
dark purple	450 ( ~842 F )
blue	540 ( ~1004 F )
dark blue	600 ( ~1112 F )

Chimera Cold Air Intake + K&N Filter DIY installed
Power Commander V Fuel Controller DIY / installed

Check out the YouTube video I made of the DIY Installed of the Cold Air Intake & PCV https://youtu.be/IMSvPnG_do0



Stage 2 Upgrading Future / Unknown Timeline / Target or Goal

Kitco Clutch Cover + Oil Cooler & Aftermarket Oil Pump
Big Bore Kit / Nikasil Liner & Piston Rings + New CAM
Autotune adapter for PCV with WB O2 sensor in exhaust pipe
Custom Mapping & Dyno Tuning to Optimize System
+1 front sprocket & -1 rear sprocket for better Highway / Freeway operation
LiFePO4 4L-BS battery // no tending & mass reduction that offsets O2 Autotune add on
Michelin Pro Pure Tires when stock rubber worn out or faded from age related degradation

Increases power to ~14 HP