1981 Big Red Problem Question

[Hunter79]

Hi all. I am a newbie here. I've had my grandpa's Honda Big Red 3 Wheeler at my house for a while now trying to figure out what's wrong with it. I've even taken it into a shop but won't be taking it there anymore because he hasn't fixed it yet and it's been there three times. Anyway, the problem is, it was running fine and then one day decided it wouldn't run anymore. To make it clear, I took it to this mechanic. He adjusted the carb and said it was good to go. I get it home, run it for about 6 hours total, and it goes back to turning over and firing, but not starting. I take it back to him, he adjusts the carb and said it was good to go. I get it home, run it for about 6 hours total, and it goes back to turning over and firing, but not starting, again. You guessed it, I took it back and told him that it wasn't the adjustment in the carb. He insisted it was and adjusted it again. You guessed it, around 6 hours and now it's doing the turning over and firing, but not starting. What in the world could be wrong? I have no idea but would really like to get this running. Also, the mechanic said that the second time I took it there the carb had completely changed where he had it adjusted to. SO, what do you think? And thanks in advance!!

[Keepah Rolln]

It could be alot of things..How long do you ride it before it shuts down? 6 hours of riding without shutting it down for a break? Maybe its over heating...

[e5earley]

When it quits, open the fuel bowl drain and see if fuel comes out. If not, your float may be sticking starving it for fuel. Just a thought.

[Hunter79]

When I say 6 hours, I mean it runs for 6 hours altogether. I've only run it for MAYBE 45 minutes straight once. But, it will run like a CHAMP for that 6 hours give or take. Then, it won't start. I know that whatever is wrong with it has to be an easy fix, I just don't know what easy fix that might be. The guy I've taken it to is an atv mechanic, but not a HONDA mechanic.

[tvpierce]

Sounds to me like he's fixing the problem, then the problem comes back.
Is he "adjusting" the carb or is he removing/cleaning it?
Is there an inline filter between the tank and carb?

[Hunter79]

He is taking the carb off and checking it to see if there's any gunk in it. He has informed me EVERY time that there's nothing at all in it. He then adjusts it to run either richer or less rich, I can't remember which, and calls me saying it's fixed. I know for a fact the carb is adjusted to the exact place he had it adjusted to last time because I put a dot on the screw and surrounding metal to ensure it hasn't come out of adjustment as he once said. I'm not sure if there's an inline filter but I will check it out asap. I should be able to work on it some over the next few days. I'll check for a filter and rust in the tank, although I don't think there's either. I just really want this thing to run and if I can't figure it out, I'm going to sell it and buy a four wheeler.

[Devilsclaw]

I had the same problem that drove me nuts for months, but I finally figured it out. Not saying that's what's wrong with yours but I can relay my experience.

Ethanol fuel was sloughing off superfine particles from the fuel system which were passing through the filter and reformulating in the carb and plugging the primary jet. Long story short, what fixed mine: cleaned out carb for the fifth time, added a second fuel filter, a 30 micron. Rolled up a tiny little cigar made of 0000 bronze wool and stuffed in the primary jet as a last ditch filter. I now use ONLY pure gasoline without ethanol, and drain carb bowl after every outing.

Also, there should be no "adjusting" of the carb. It should be set to 100% factory spec, and only adjust the idle speed as required. Of course this requires the mechanic to actually look up what the factory jetting, float height, and fuel level should be. Most grease monkeys don't want to have to do all that extra readin and stuff! (Assuming no engine or intake mods)

This is just my experience, but sounds a lot like what you are going through.

Best of luck!

[Hunter79]

I had the same problem that drove me nuts for months, but I finally figured it out. Not saying that's what's wrong with yours but I can relay my experience.

Ethanol fuel was sloughing off superfine particles from the fuel system which were passing through the filter and reformulating in the carb and plugging the primary jet. Long story short, what fixed mine: cleaned out carb for the fifth time, added a second fuel filter, a 30 micron. Rolled up a tiny little cigar made of 0000 bronze wool and stuffed in the primary jet as a last ditch filter. I now use ONLY pure gasoline without ethanol, and drain carb bowl after every outing.

Also, there should be no "adjusting" of the carb. It should be set to 100% factory spec, and only adjust the idle speed as required. Of course this requires the mechanic to actually look up what the factory jetting, float height, and fuel level should be. Most grease monkeys don't want to have to do all that extra readin and stuff! (Assuming no engine or intake mods)

This is just my experience, but sounds a lot like what you are going through.

Best of luck!

I am going to work on it tomorrow. I've been told some of the same thing you're saying. I am going to check the tank to make sure there's no rust. I'm also going to clean the carb again and put on an inline filter. I sure hope this works. It's FRUSTRATING!! Of course, I have no idea how to put in an inline filter but I guess I'll just have to learn!

[Devilsclaw]

It's easy just cut the fuel line, and plug it in. Make sure it's the right size for your fuel line. Also, once you have it installed, disconnect the line at the carb, and allow it to flush out for a while. This helps to purge any debris that you may have dislodged by manipulating the fuel line. Actually, replacing the entire fuel line isn't a terrible idea.

I can see why the "mechanic" thought the setting had been changed. Mine was the same way. What was actually happening though was the setting had not changed but the fuel amount being delivered HAD. These machines are so old that even when they are "clean" there still is years of accumulation of microscopic junk in there that gets dislodged.

It can make you crazy but it can be fixed.

PS: the fuel filter is directional, look for an arrow that points to the direction of flow.

[Jmoozy27]

What kind of tank is it? Plastic or metal. You may have a vent problem causing the tank to vapor lock after running for six hours or so and not allowing fuel to get to the carb. Just a thought.

[Hunter79]

What kind of tank is it? Plastic or metal. You may have a vent problem causing the tank to vapor lock after running for six hours or so and not allowing fuel to get to the carb. Just a thought.

It's a metal tank. The vent on the cap is working because I ran it in the off position until it died. I then turned it back to the on position and it fired right up and ran, until the 6 hour time limit that is. Maybe that's not what you're talking about though?

[Jmoozy27]

That's what I was talking. It was worth a shot. Go ahead and go through your combustion triangle. Air, Fuel, Spark... One of them has to be the issue. Sounds electrical.

[Hunter79]

Well, I just got back in from looking at what I feel I'm halfway qualified to look at. I took the tank off and completely emptied out the gas. I ran my finger inside of it to see if there was any rust residue, there wasn't. I then looked at the gas line. I didn't realize it but when I took it to the mechanic, he had already changed the gas line between the tank and carb. He also put in an inline filter. So, that's not the problem. I replaced the gas with premium gas after putting the tank back on. Just for the heck of it, I tried to start it. It started right up and ran perfectly at an idle for about 10 minutes. All of the sudden, it died and now won't start again. I don't know what to do now as I just don't feel qualified enough to take the carb off. I'm afraid I'll break something on it and I know it's not cheap to replace it.

[e5earley]

Open the drain screw at the bottom of the fuel bowl and make sure you're getting fuel into the carb.

[86125m]

Well for one thing there isn't such a thing as an 81 big red if i could gets some pics I could id the trike. But it does sound like your carb is getting stopped up might be time for a new carb