Let’s start from scratch. I bought the bike from a guy in Virginia and the bike worked great etc. a few days goes by of riding and I heard a weird noise coming from under the gas tank. Quickly figured out it was the cam chain tensioner so I replaced that. Ended up leaving the bike on and the battery died. Ended up getting a new battery and that one ended up dying after a week of riding so I got a new one cause that one tested bad… again the same thing. Figured out that I needed to replace the regulator and stator. Everything went well after replacing and started riding. A couple weeks went by and it’s been fine until yesterday. I was going downhill and the bike bogged out even with low or high throttle just kept bogging out. As I was going down the hill I kept bump starting it to cause I had motion and it would start but kept bogging out. Pulled over and it wouldn’t start. The fuel pump primes, there are no codes, all the lights come on, and it turns over but just won’t get the bike started. Don’t know if while I was trying to start it up again while going down the hill I blew a fuse, spark plug went bad or what. Just trying to get the bike started in order to figure out the bogging issue. And I got the battery tested yesterday just to see if my replacement job of the regulator and stator was good and the battery was great and is being charged. Any ideas of what it could be?

 

Spark plugs or coil I'm guessing.

 

Extremely unlikely that all 4 plugs or coils would die at exactly same time. Usually one dies 1st and you can still run on 3-cylinders. Wouldn't even notice that unless you measured 1/4-mile times with stopwatch because bike has so much power, you'd never notice the missing cylinder.

If you just don't want to test and measure to let the numbers tell you exactly what's wrong and how to fix it (most likely broken wire), you might as well swap out entire EFI system. ONLY get brand-new factory OEM parts from authorised Honda dealer because they're so many crappy 3rd party aftermarket parts that are bad right out of box. Each new part needs to be tested and measured to verify functionality before using.

Do in order all at once:

32100-MBW-A10 - main wire harness
32104-MBW-D20 - injector sub-harness
32102-MBW-610 - ignition sub-harness
32101-MBW-J20 - engine sub-harness A
38770-MBW-A12 - ECU
16400-MBW-A12 - throttle bodies+ TPS matched set
06164-MBW-J21 - injectors x4
30700-MBW-611 - coils 4x
35160-MBW-D22 - BAS sensor
36140-MBW-J21 - cam position sensor
30300-MBW-J21 - crank position sensor
37830-MCF-003 - MAP sensor
37880-P05-A00 - IAT
38380-MBW-D21 - relay
38501-GAM-007 - relays x2

You probably didn't replace stator & RR with brand-new factory OEM parts from authorised Honda dealer, which is why it's not charging battery and killing them. Remember, ONLY buy brand-new factory OEM parts from authorised Honda dealer! Otherwise you're wasting time and money by having to go back and replace again!

 

any chance it could be the carb clogged up or bad gas. It was working fine except at idle it would fluctuate. I was riding downhill and it bogged out and I had gotten gas prior and now it just won’t start. I don’t think it’s an electrical problem because the battery is fine and charging like it should. The bike primes and wants to start but doesn’t which is why I think bad gas could be it or the carb. I don’t have a whole lot of time and money to try and fix it which is why I’m trying to start with easy things first. Worst comes to worst I could take it somewhere but I would hate if it was an easy fix such as cleaning the carb or something of that nature.

 

Dirty clogged carbs take time to affect bike. Stumbles, difficulty starting that gets worse and worse for months before it stops working. Doesn't happen in an instant unless you throw handful of dirt into carbs. Even then, it's unlikely to clog all 4 carbs identically. Besides, you don't have carbs, but fuel-injectors. But same idea. Clogging takes time and gets progressively worse and worse overtime. Electrical problem happens in an instant.

You don't have to spend much money at all, probably none as this is most likely broken wire somewhere. To isolate problem area for closer look, do some testing

1. flush all petrol from tank. Remove tank, remove fuel-pump assembly and dump out all contents. It may be possible you got bad batch from last filling station. Fill with fresh 87-oct petrol (doesn't sit around and get stale like higher-oct stuff). Also burns and ignites easier. Might need to crank engine for minute or more to flush out old stuff from fuel-lines & injectors. Does bike run with new petrol?

2. bypass fuel-system. Use squirt-bottle to spray 2-3cc petrol into airbox. Wait 15-sec for it to vapourised. Then start bike. Does it run?
(BTW, DO NOT use starting-fluid on carbs, it has ether and will melt carb-diaphragms).

3. test for spark. remove one ignition-coil. Insert spare spark plug into it. Ground case of plug against bare spot/bolt on engine. Start engine. Do you see bright blue spark jump plug?

Here's wiring-diagram. Blanked out lights as they're not related to your starting issue. We can rule out battery, battery-cables, starter and stator/RR as those are working. BUT ALL OTHER wires, sensors and electrical components are suspect and we need to test to find which one is broken. Each and every one of them has test-procedure in manual to determine if it's good or defective.



This is just like building a house. Lots of little steps and you just have to do it one brick at a time and in end, it'll be done! You can't just "think" about problem to fix this bike. Need to get hands on and test in sequence and measure to find numbers. Some number somewhere won't match up with what manual says it should be and that's where we look closer for problem. Do those 3 tests above to get started.