Honda Big Red backfires, won't start. Please help.

[kormos_93]

O.K, so I picked up a 1984 shaft drive Honda ATC the other day really cheap, it was sitting outside for 2 years but everything seemed to be in good shape. Anyway, I cleaned the carb, checked valve clearance, timing chain, timing, plug, fresh gas, etc..& all it does is backfire. I can pull it over & it fires but it wants to rip the cord out of my hands whenever it fires & pops really loud out the carb (I checked to see if the air filter/exhaust was plugged & they weren't). I got it to fire up once for about 3-4 seconds, but it ran really sluggish & died. Did the same thing again 30 pulls later. Now I can't get it to run at all, it just backfires every 5-6 pulls (reason I am not using the electric start is because the splines on the starter gear were stripped. I don't know if this matters, but the sparkplug I took out had a LOT of carbon buildup (the one the machine came with), so I put a new one in. The prevoius owner said he never had it running, but as far as he knows it was working fine 2 years ago. Sorry for typing a novel, any advice you could give me would be appreciatedThanks(I've got 7 hondas & never had a problem like this, even had one that sat in a field for 18 years that runs fine after a good carb cleaning).

[barnett468]

Hello


"The prevoius owner said he never had it running, but as far as he knows it was working fine 2 years ago."

OK Yeah.

1. When did you install the new plug before or after you got it running for 3 seconds?

2. Does the old plug look black and DRY or is it black and “GOOEY” looking? Dry would be rich which in your case could be caused by a few things. “Gooey” is oil but now that you may have soaked it with gsas it might be hard to tell.

3. Was there old gas in it when you got it?

When a full tank of gas dries up in a tank it can sometimes leave a tar like substance on the bottom. New gas can re emulsify this residue and cause new gas to burn more poorly but likely not your problem unless gas is now looks apple juice color.

4. Drain float bowl via drain screw into clear glass, what color is gas, any sediment, any water? Water in fuel will cause this also.

5. Check for intake leak.

6. Is it getting gas into cylinder ie is plug getting wet from gas.?

[kormos_93]

Hello


"The prevoius owner said he never had it running, but as far as he knows it was working fine 2 years ago."

OK Yeah.

1. When did you install the new plug before or after you got it running for 3 seconds?

2. Does the old plug look black and DRY or is it black and “GOOEY” looking? Dry would be rich which in your case could be caused by a few things. “Gooey” is oil but now that you may have soaked it with gsas it might be hard to tell.

3. Was there old gas in it when you got it?

When a full tank of gas dries up in a tank it can sometimes leave a tar like substance on the bottom. New gas can re emulsify this residue and cause new gas to burn more poorly but likely not your problem unless gas is now looks apple juice color.

4. Drain float bowl via drain screw into clear glass, what color is gas, any sediment, any water? Water in fuel will cause this also.

5. Check for intake leak.

6. Is it getting gas into cylinder ie is plug getting wet from gas.?

1. Plug was installed before I got it running
2. Old plug was dry & carbony (I never soaked it in gas)
3. I put a clean gas tank with fresh gas on from my yamaha (& I drove it over to the trike before I swapped the tank over)
4. I had the carb off & cleaned it, it looked clean when I took it off (there was no gas in it, there was also no oil in trike (sort of strange))
5. I will have to do that, have not checked the black intake boot/insulator yet
6. Yes, the plug is wet

I am thinking it has to be a fuel/air problem, I have checked everything electrical including valves & timing & it appears to be fine. I did actually have a similar problem with my 200m, but it didn't want to rip the pullstart out of my hand when it backfired, it just sort of made a small pop-pop & refused to run at all. All I did to the 200M when it did that was take the carb apart, look at it & put it back on & it somehow fixed it....?...possible air leak as well perhaps?.........Wish I knew how I fixed that one so I could do the same to the Big Red.

[kebby28]

Could also be the coil. Hows the spark? Strong and constant? Sometimes even if it looks ok they can still be not enough.
I always have a little fear pulling those 200's over. Running good or bad I've had them rip the pull chord out of my hand and pull serious muscles...
That is very strange there was no oil in it... Did it take 1 or 2 quarts? If you just pull the plug on that 200es then it will take 1. If all the oil dissapeared then it would take 2...

[kormos_93]

The spark isn't great, but it's there. I have seen ATCs spark after putting all new parts on them & seen the spark on ones that have been ridden hard for 30 years & this one would be about a 5 or 6 on a scale of 1-10 (1 being the weakest spark I've ever seen). From past experience, anything that had some sort of spark would run (crappy), but would still run. The worst part is that I can't even throw parts on it from one of my running trikes to see what the problem is because the rest of my trike collection is 600 miles away....Frustrating

[kormos_93]

Well, I re-cleaned the carb, checked for air leaks & nothing. When I set the sparkplug against the head, there is definitely visible spark but when I put the plug in now it doesn't even backfire anymore. The plug is wet, it's definitely getting gas now because gas runs out the carb when I put the choke on. There is spark when it's out but it doesn't fire when I put it back in (tried a couple different plugs).......It seems to be losing spark under compression....what would cause this? ?

To answer questions, it took about 1 1/2 liters of oil, I will try a different coil when I head home sometime this week & can access my parts.

[kb0nly]

Losing spark under compression and the problems your describing is exactly what i have been through with two 200ES's now, it was the CDI both times. Its very very rare that the coil goes bad on these. Generally its stator or CDI problems.

[ps2fixer]

I have seen a lot of people with CDI problems in the past, luckly my 2 machines I got running with little to no work .

You can test if it is a carb or air/fuel mix problem by using a map gas torch. Basically turn the gas off, drain the carb, and stick the torch down in the carb and just turn the gas on (don't light it lol). This also helps dry the cyl out if it is flooded. If timing/spark etc is good, it should idle, giving it gas will make it run lean and probably die. I have never had a backfire light the torch, but make sure you understand the "risks" of this method and the fact you are puting out a gas/air mix that can "explode" if you don't try to start the machine right away.

I tried to find a youtube video on how it is done, but I guess this trick isn't all that popular?

[kormos_93]

I know CDI problems are pretty common on these (I've changed 2 of them), but on both occasions I had no spark at all so I didn't think it would be CDI that was the issue this time. I have a spare one I will throw on in a week & see if that fixes it. Thanks for letting me know you had a similar issue. I figured that if it had spark, the CDI must be working....& yes I see a lot of people running the original coil from the 80's, I've never had one that was bad.

Oh, & that gas testing method sounds a bit too risky for me. I managed to set the garage workbench up in flames when my exciter 440 snowmobile motor backfired one time.

[barnett468]

Hello

Try changing coil too if you still have problems, just try one item at a time.

[barnett468]

Hello

"The plug is wet, it's definitely getting gas now because gas runs out the carb when I put the choke on."

If you choose not to shut gas off and spray carb cleaner in carb to check fire [which is understandable] then you need to fix your carb flooding problem first or it will never start.

[ps2fixer]

Hello

Try changing coil too if you still have problems, just try one item at a time.

I thought the charging coil was just for the charging system and lights. I have hard of the exciter coil causing problems with weak spark though.

[barnett468]

I thought the charging coil was just for the charging system and lights. I have hard of the exciter coil causing problems with weak spark though.

Hello

Not "charging" coil, try "changing" coil. you must have a small screen or bad eyes like mine, lol.

[ps2fixer]

Hello

Not "charging" coil, try "changing" coil. you must have a small screen or bad eyes like mine, lol.

I just miss read it sorry lol, it is 1:30am here .

[kormos_93]

I'll change the parts when I have a chance & let you guys know how it goes.