Working on an 07 Rancher 420 2wd.

When I got it, it had been sitting for well over a year. Was parked after it got wrecked in the front end, but apparently still ran fine and even could be driven around.

When I got it home I put about half a gallon of fresh gas into it and hooked a jump box too the battery, I just wanted to hear it run. To my excitement, it fired right up and ran great! So long as the jump box was hooked up, as soon as you disconnected the jump box it died. But I figured that was just because the battery that was in it was completely flat...

So with the jump box still hooked up, I let the bike run for about 5 minutes or so, then it spit and sputtered, then died, and would not restart...

I figured the fuel had probably gummed up in the filter after sitting for so long, so I ordered a filter kit for it. Today I got around to changing the filter, and WOW was it nasty... see below... The filter change went well, I drained the tank and put a full tank of fresh gas into it, and I got it all back together (the fuel pump/filter assembly anyway). Hooked the jump box back up, turned the key a few times to prime the system and hit the start button, and it fired right up! All for about 15 seconds before it did the same sputtering and then died and wouldn't restart...

So my next move was, after seeing the condition of the fuel filter, to see if the injector or the line going to it had a clog. I pulled the line of the injector at the throttle body, there was definitely still pressure in the system... Aimed the line away and turned the key, shot a bunch of fuel out to purge the line. Then pulled the injector off. Didn't really look too terrible, but I shot it with some carb cleaner. I know that's not going to fully clean it out, but it was worth a shot. So I put it all back together. Tried to start it, but no dice...

So I figured well, pretty sure we're getting fuel, I guess let's check spark. I pulled the spark plug out and it was wet with fuel... So yeah, it's getting fuel for sure. I held the plug up to the engine and turned the motor over, I'm getting no spark... go figure... I checked for power at the coil terminals. One side is hot with the ignition on, the other side switches ground on when turning over, so I assume that's how it's suppose to operate electrically?

Is it safe to say that the coil is just bad? Coincidence? Or possibly caused by running it with a shot battery and just a jump box (highly unlikely I would think, but this is the first Honda I've ever messed with, heck the first fuel injected quad I've ever messed with, so who knows...)


Pictures attached of the old fuel filter situation... The new one I installed was the updated one that has the filter attached on the side instead of directly on the bottom of the bowl.

 

I would try a new coil, but don't use a "jump box". Not certain bout the durability of electronics on EFI systems but I was warned years ago by a Yam dealer that jump boxes cook the Yamaha 4WD motor if you click into/out of 4WD with a jump box on the battery, so never use them on EFI bikes. I would blow the injector out too, those tea bags are not that fine and the injector filter picks up what gets through them.

 

I'm going to try a coil first. Ordered a used OEM Honda one off eBay, figured that's got to be better than an off-brand cheap Chinese one...

I will try throwing a battery from one of my Yamaha's in it and see if that will get it started.

Injector definitely seems to be working, it's getting fuel into the throttle body and engine. First hint that there was fuel and just no spark was when I tried a little shot of starting fluid and it did absolutely nothing...

 

Well I installed the coil today, still the same situation...

Only now when turning the engine over, it has a spark, but a VERY weak one. Oddly enough, every once in a while, it'll try to fire, might get two or three strokes to fire, then goes back to nothing... Seems to be totally random.

I messed around with the wiring, checking grounds, every plug I could find, tracing wires to make sure there was no chafing or broken wires anywhere that I could see. Even pulled out all of the electronics in the compartment under the seat, unplugged and reseated the plugs, put a battery in it that actually has juice. Still nothing... I'm at my wit's end with it.

One last ditch effort I'm going to try, which is probably something I should have started with, I'm going to throw a new spark plug in it just to see... I don't THINK that's all it is since it tries to run every once in a while, but before I just cut my ties with it and sell it off as-is, it's worth a shot...

 

I cannot believe I'm posting this, but...

I put a new NGK spark plug in it, and the damned thing fired right up. Rode it around for about 30 minutes, didn't miss a beat. Shut it off, and it fired right back up.

So yeah I feel kinda dumb for not trying a simple and cheap thing like changing the spark plug first lol but am I ever glad that's all that it was!

It actually had the wrong plug in it to begin with, a 7 in the part number instead of a 5. Different heat range I assume? But weird that it was running before with it and then suddenly not...

 

I have been fooled more than once with thinking that a non runner had fuel, or deep electrical problems, only to find it was the plug, so now usually stick another plug in at the start of checking. Can also be a faulty fuel system such as yours had can "wet" the plug. So you fix the fuel system but by that time the plug is soaked in fuel and won't fire up.