Hello. I have been rebuilding and F4i for the last 6 months and am having issues with the wiring harness. After puting in a new motor, and rebuilding the bike to its naked state it is currently in, im trying to get it to start. initially i thought its was the zener diode problem i know F4i have issues with. i ordered a woodcraft ignition delete with zener diode to confirm that was not the problem. with the delete in place, when ignition flips on, there is no fuel prime, nore spark when ignition is pressed. starter engages and she cranks just no fuel or spark. i have done all the sensors, neutral, tip over, kickstand, etc to ensure those werent the problems. The two relays behind the seat viberate when ignition is on giving me the impression of them doing well. the headlight harness is not attached and the tip over sensor is bypassed on the main harness. I have 2 ECUs ive been using to test to see if that was the problem but both show the same results. anyone have any idea on where i should start.
she has new spark plugs
new fuses
new oil

 

Welcome to the forum.
AFAIK the bike will not start without the headlight Harness being attached. I stumbled across this in the past when I also had the headlight and associated loom disconnected and mine would not start.

 

then how am i seeing a bunch of naked f4i's for stunting?

 

There’s difference between “headlights” vs. “headlight harness”. Headlight harness has BAS, that’s required for ECU to run. Can leave headlights off.

 

This is 5-minute fix for free with multimeter to measure.

Put all original factory OEM parts back on if you didn’t replace with brand-new factory OEM parts from authorised Honda dealer. Aftermarket 3rd party parts are notorious for being low-quality. Many of them are bad right out of box. Needs to be tested and measured to confirm functionality before using. For that effort, might as well test and measure OEM parts on bike and fix it in 5-minutes.

No pump prime is ONLY related to BAS, nothing else disables it. Install headlight harness with BAS and pump will run properly.

No spark is safety-interloc circuit. Clutch, sidestand and neutral switches form AND/OR logic circuit with diode to tell ECU there’s unsafe condition and it kills spark to stop engine. Measure each and every switch and its wiring at ECU connector. Should show switch is connected to ground, then ECU will fire spark. If more than 1-5 ohms on safety line at ECU, it won’t fire sparks.

Simple 5-min fix with 2-3 measurements max to determine which switch or wire is broken or connector unplugged. I’ve helped over 100 people fix this exact problem in remote dark parking lots in middle of night. Sometimes in pouring rain!

 

I dont have the OEM parts. as i said this is a complete rebuild. as in im ordering parts as i need them. the killswitch operates fine, the ignition delete is working. i bypassed the TOS on the main harness jst above the headlight harness plug. i know the bypass is working because when i detatch the two wries no power goes to the relays, but when they touch they do. checking the wirs i will and get back to you. where is the safety wire on the ecu

 

Ignition bypass has nothing to do with fuel-pump prime. It only turns on basic power to ECU, lights and dash. Only BAS on headlight harness turns ON fuel-pump prime. As soon as it’s connected, fuel-pump will prime.

Safety lines on ECU is lt.grn and grn/wht. Connect to neutral, clutch and sidestand switches through diode according to wiring diagram and you’ll get spark.

Clutch switch has 2-states and tells ECU which ignition-map to select. In squeezed state, ECU picks basic idle map. In released unsqueezed state, it picks optimum power map. Make sure clutch switch is working properly with distinct squeezed/un-squeezed states and it’s going through diode properly. Otherwise you’re using basic idle map and sacrificing lots of power.