So with this info spread across many threads, misconceptions and sales threads lacking COMPLETE info I think it's time for a thread for discussing the FinBro ECM outside of the "sales/marketing" side. I've done this mod to one of my 2 Groms, will be performing on the other one sometime after the Holidays. It'll be the only computer you'll you ever need short of a complete engine swap from a different bike. This will work with most if not all of the BBK kits including ones from Takegawa and Koso.
Rodzknight (Franco) at FinbroGarage.com was the one that had the idea, suggested it and convinced Awirut (aka Monkey Father) who owns FinBro to get his 147/153/155/158/163/170/183/193/198/204/204-4V/212/218/222/235 computer matched up with proper injectors and working with the smaller builds. Yes that one ECM takes care of ALL of those! So everybody from simple exhaust and intake mods worried about running their engines dangerously lean to smaller big bore kits etc... can use the FinBro ECM and just upgrade their engines as it suits their needs. Without his foresight and shepherding this through Awirut (MonkeyFather) at FinBro we would not have this as a option.
As I understand it the ECM is a Honda CBR250 unit (not verified, but thats the rumor) manufactured and modified by Keihin with FinBro's specs. This is the SAME company that builds and supplies Honda with the OEM Grom computer and injector.
Benefits & Limitations:
This ECM has NO end user adjustable parameters.
It's slightly longer but fits in the stock location easily.
14 Grams heavier than the stock ECM (92g vs 106g)
It AutoTunes for a corrected Air Fuel Ratio (AFR) of 12.5:1 (stock is about 14.7:1) (see Note)
Voids your warranty (like all the others)
No need for Wide Band O2 sensor and welding a Bung to your Exhaust.
Eliminates Safety Kickstand Kill Switch.
Eliminates Fast Idle Solenoid so bike WILL be cold natured at startup.
Eliminate Intake Air Temp Sensor (IAT)
Eliminates Charcoal Canister/Purge System
Eliminates Altitude Setting
Installation:
Requires moving RPM Signal Wire (pin #28 yel/grn stripe) to a previously unused location on the same ECM connector (pin #7). (wire supplied, you will need to solder, heat shrink)
Requires removing/cutting Factory Check Engine Light (CEL) wire at pin#22 on the connector (wht/blue stripe) (if you don't want it to stay on)
Optional Complete FinBro harness is available if you don't want to modify your harness connectors (as described in 2 points above)
Replace Factory Injector with recommended one from FinBro for your sized Engine.
Go ride, it'll learn and adjust as you go. First ten minutes is the roughest. Do full pulls, wide open throttle (WOT) up and down the gears.
Enjoy.
This eliminates the need for $600+ in DynoJet Power Commander, API tech, Bazazz, Wideband 02, Exhaust Bungs, welding exhaust, Gauge Package, etc... UNLESS you like that stuff.
You just swap the injector and fuel line when you move up from a 125 to the bigger engines. You will always need the proper injector which other threads don't mention when they try to sell this to you. The Factory Injector is not used in ANY of these applications including the base 125 configuration. It's all about Flow Rates, Duty Cycles and Range. FinBro has already figured it all out for us.
Engine Sizes & Required Fuel Injector:
125 up to 163cc - Honda/Keihin PCX-150 injector (pn 16450-KZY-701) Injector sounds significantly different. Don't be concerned by the clicks when first turning the key on - it's normal.
170 to 198cc - 6 Hole Keihin Injector
204 to 235cc - 10 Hole Keihin Injector
not listed here: Please verify with FinBroGarage and see Footnote 1.
The upgraded Honda Forza (279cc Scooter) Fuel Line (pn 17528-K04-931) is only $30 thru Franco and it's a little more through Honda themselves but is available Stateside. It is NOT Recommended that you change the fuel line unless you are directed to do so. It does change the AFR parameters if you jump the gun.
Fuel Line Requirements (Note: For all unlisted CC's please see Footnote 2):
125cc - Stock Fuel Line (confirmed)
Finbro 183cc - Forza Fuel Line (confirmed)
Finbro 218/222/235 - Forza Fuel Line (confirmed)
Personal Observation/Note:
We have air cooled bikes, some are heavily modified. Every precaution is taken to eliminate issues but if you pound on it long enough, sit in traffic on a 100 degree day, etc... you can have issues. Oil coolers are always a good thing too, even on a otherwise completely stock Grom. If you are one of those people, then gauges to monitor the Engine like AFR and Oil Temp is never a bad idea.
Notes:
The Autotune Feature shoots for 12.5:1 at all times but on a Completely Stock, restricted setup it can only achieve 13.1:1. Once you start to open up the intake and exhaust you will see it get down to its optimal AFR rate.
If you are running a 4 Valve from Koso or Takegawa please verify with Franco @FinbroGarage what is the proper injector/fuel line for your setup. Will update this article as more info develops.