Running rich
1 - 20 of 55 Posts
Joined
·
5,683 Posts
There’s a few of us that can help you.
What’s your altitude above or below 3000’ ASL?
Is your air filter clean? Not too much oil?
How long you had this quad?
Do you have a service manual—click link in my sig block below—trx350 Foreman covers all these models.
I say check your throttle synchronization and your idle screw setting—try 1.5 turns out.
What’s your altitude above or below 3000’ ASL?
Is your air filter clean? Not too much oil?
How long you had this quad?
Do you have a service manual—click link in my sig block below—trx350 Foreman covers all these models.
I say check your throttle synchronization and your idle screw setting—try 1.5 turns out.
Joined
·
33 Posts
Thanks for responding guys. I have the manual. Pulled the carb and changed the jets. Put in factory spec jets. Set the needle to the middle setting as instructed per the manual. Cleaned everything and set the pilot screw to 1 1/2 turns. I did all this because someone put a crappy aftermarket pipe on it. I found an original and installed it. After doing all that it won't idle. Runs on choke and blows black smoke so I know it's rich. I had the pilot screw to being out only a 1/2 turn, still wouldn't idle and blows black smoke and backfires when you stay on the throttle to keep it running.
Joined
·
33 Posts
I've had it about two years, it ran ok with the crappy pipe but still backfired. Now it will only stay running with the choke on. I've spent a lot of time on it making it all original again. Love this thing. I have a few other hondas as well, mostly atcs. Just can't get this baby going and it's also my plow. Got snow coming tonight.
Joined
·
5,683 Posts
If backfiring I think there’s an air leak somewhere. check to make sure the carb is seated in the boot on the engine side. You’ll feel a definite detent when it seats Also check your starter (choke) valve have you ever replaced it—could be the valve sticking so your valve’s not seating
Added pic of jet numbers
Added pic of jet numbers
Attachments
Joined
·
33 Posts
The starter valve is the choke right? I removed it when I took the carb out to do the jets. It looked good so I put it back in as instructed by the manual. Even if it seems ok can it still be bad? Wasn't frozen, dirty or corroded, moved freely. I've not replaced it. As far as seating in the boot, I felt two seps of detent. Checked that twice, it snaps in and holds the carb square. No holes in the boot, sprayed around it with either, no leaks.
Joined
·
33 Posts
Pulled carb out again, choke is still free. Checked jet sizes, they match your pic of jet sizes. Put all back and still won't idle. I'm at a loss here. New fuel pump, fresh fuel, new plug. Carb set to what manual instructs. Still won't idle for a second. Runs with choke full on or half on with backfires and some black smoke.
Have you adjusted the valves? They should be set at .003" on a cold motor, with both cam lobes facing down and the motor at TDC on the compression stroke. Its in the manual...
Is the entire exhaust including muffler stock now? No leaks?
Is there a NGK spark plug in it?
Do you have another OEM ignition coil and spark plug wire/boot laying around that you can swap onto it to eliminate that possibility?
Can you take the choke off while riding the bike as long as you aren't idling? How does the motor run with choke off while accelerating... does it make good power?
Welcome to the forums!
You probably knew this was coming... but do you have any pics of your purdy old gal you can share with us?
Thanks!
Is the entire exhaust including muffler stock now? No leaks?
Is there a NGK spark plug in it?
Do you have another OEM ignition coil and spark plug wire/boot laying around that you can swap onto it to eliminate that possibility?
Can you take the choke off while riding the bike as long as you aren't idling? How does the motor run with choke off while accelerating... does it make good power?
Welcome to the forums!
You probably knew this was coming... but do you have any pics of your purdy old gal you can share with us?
Thanks!
Joined
·
33 Posts
Ngk plug, stock full exhaust, you can ride it and it makes good power but backfires as soon as you let off and almost dies. I didn't adjust the valves, I don't believe that or the cdi is the problem since before this it ran decent. I just wanted to jet the carb and set it correctly since the jets were different with the other pipe. I'm just missing something small I think. Needed a few insites to help me figure it out. I'll post some pics. These are without the plow. I'll have to take some with it, it's painted to match.
Attachments
That is a sharp bike you got there!!! Thanks!
Ok, lets rule out ignition breakup and overly tight valve lash for now. Back to the carb and jetting...
Are the brass jets you replaced in the carb OEM Honda, or from an aftermarket kit?
Did you clean the carb with any type of solvent? If so, were all rubber and soft parts separated from solvent exposure while cleaning the carb?
The small rubber plug must be in place (and in the correct hole, see Goobers photo above) inside the bowl.
The float valve should be OEM and the float level pretty close to spec (.73", or about 3/4" with carb inverted).
The needle jet and needle jet holder must be installed in the order shown in the attached image. The Jet needle clip should be in the center groove.
The two tiny o-rings must be on the pilot screw during reassembly to seal it. See attached image.
The fuel filter must pass fuel readily and fuel lines must be clear with no kinking. OEM formed fuel lines preferably... it should have an OEM electric fuel pump as well.
The top cover must be sealed well with a gasket in good condition as shown in the attached image.
If everything is OK in the above list, open the drain screw (with the motor shut down) on the bottom of the float bowl and allow all fuel inside the carb to drain into a small container through the drain hose. How much fuel drained out?
Venting and air supply... compressed air comes in handy here.
Check that the fuel cap vent (its tiny and plugs up easily) and fuel cap vent hose are not kinked or plugged up.
Check that the vent hoses that attach to the sides of the carb are installed and routed correctly and clear with no kinks or plugged hose ends. See the manual for routing info or ask us here if you aren't sure.
Lastly, blow out the small round air passage well (circled in red in the attachment) while all jets and the choke valve and the top cover are removed from the carb, so that you won't plug up your clean jets or blow up any delicate parts. This step is very important, because all air entering the carb through that port is used for emulsifying fuel in the starter valve (choke) circuit, the pilot (idle mixture) circuit, and the Needle jet (off-idle and above) circuit and even the main jet circuit gets some of this air.
If I had to make a guess what is causing your idle problem, a blockage in this air supply port would be my top pick. It must be clear all the way through to the backside of the throttle butterfly (look closely you'll see one or two tiny holes in the bore when you open the throttle butterfly) valve.
Let us know if anything was found wrong with all that...
Ok, lets rule out ignition breakup and overly tight valve lash for now. Back to the carb and jetting...
Are the brass jets you replaced in the carb OEM Honda, or from an aftermarket kit?
Did you clean the carb with any type of solvent? If so, were all rubber and soft parts separated from solvent exposure while cleaning the carb?
The small rubber plug must be in place (and in the correct hole, see Goobers photo above) inside the bowl.
The float valve should be OEM and the float level pretty close to spec (.73", or about 3/4" with carb inverted).
The needle jet and needle jet holder must be installed in the order shown in the attached image. The Jet needle clip should be in the center groove.
The two tiny o-rings must be on the pilot screw during reassembly to seal it. See attached image.
The fuel filter must pass fuel readily and fuel lines must be clear with no kinking. OEM formed fuel lines preferably... it should have an OEM electric fuel pump as well.
The top cover must be sealed well with a gasket in good condition as shown in the attached image.
If everything is OK in the above list, open the drain screw (with the motor shut down) on the bottom of the float bowl and allow all fuel inside the carb to drain into a small container through the drain hose. How much fuel drained out?
Venting and air supply... compressed air comes in handy here.
Check that the fuel cap vent (its tiny and plugs up easily) and fuel cap vent hose are not kinked or plugged up.
Check that the vent hoses that attach to the sides of the carb are installed and routed correctly and clear with no kinks or plugged hose ends. See the manual for routing info or ask us here if you aren't sure.
Lastly, blow out the small round air passage well (circled in red in the attachment) while all jets and the choke valve and the top cover are removed from the carb, so that you won't plug up your clean jets or blow up any delicate parts. This step is very important, because all air entering the carb through that port is used for emulsifying fuel in the starter valve (choke) circuit, the pilot (idle mixture) circuit, and the Needle jet (off-idle and above) circuit and even the main jet circuit gets some of this air.
If I had to make a guess what is causing your idle problem, a blockage in this air supply port would be my top pick. It must be clear all the way through to the backside of the throttle butterfly (look closely you'll see one or two tiny holes in the bore when you open the throttle butterfly) valve.
Let us know if anything was found wrong with all that...
Attachments
Joined
·
33 Posts
Thanks guys for the info and pictures!!!! I'm going to go through the carb again checking all of these things later today. I gotta get my father in laws truck to plow the driveway and get everything cleared out. I really appreciate any and all the help you guys can give me!!!! As so as I get done with the carb and try it again I'll post the results.
Joined
·
121 Posts
How did you get your carb so clean looking? Looks GREAT!
Joined
·
5,683 Posts
LOL it was a salvage find! I bought it for $40 as a spare so I could swap out with my 86 and 4 other 87s. A funny story.
My sis-in law lost her cat here while on summer vacation. About a month later while I was working on the carb in the garage this cat would look into the back door. And would dash away when I saw it.
So I extended my work on the carb, polishing the outside with toothpaste and aluminum polish. Buying a new float and stuff; pipe cleaners thru all the passages, and put out cat food. Clanked on the dish when I got ready to work and eventually the cat started to accept food. Gradually moved the dish inside; the cat would eat, snoop around and bolt. Every night I did this until one night the cat came in, ate and hopped onto the seat of my ATV.
At that point I shut the door, recapturing the kitty. She slept on the atv for two weeks while I made sure she didn’t have rabies.
I was then able to install the carb on my 86, get it tuned, and put it back into the box for the winter! This spring I’ll swap it out with a carb that’s been giving me troubles–and rebuild that one too.
So after all that I spent a month and $200 overhauling a carb! 2 cans of Chemtool, swabs, brushes, pipecleaners starter valve, float, main jet holder, 138.5 jet–not counting cost of cat food and litter
She loves being in the garage on the ATV
My sis-in law lost her cat here while on summer vacation. About a month later while I was working on the carb in the garage this cat would look into the back door. And would dash away when I saw it.
So I extended my work on the carb, polishing the outside with toothpaste and aluminum polish. Buying a new float and stuff; pipe cleaners thru all the passages, and put out cat food. Clanked on the dish when I got ready to work and eventually the cat started to accept food. Gradually moved the dish inside; the cat would eat, snoop around and bolt. Every night I did this until one night the cat came in, ate and hopped onto the seat of my ATV.
At that point I shut the door, recapturing the kitty. She slept on the atv for two weeks while I made sure she didn’t have rabies.
I was then able to install the carb on my 86, get it tuned, and put it back into the box for the winter! This spring I’ll swap it out with a carb that’s been giving me troubles–and rebuild that one too.
So after all that I spent a month and $200 overhauling a carb! 2 cans of Chemtool, swabs, brushes, pipecleaners starter valve, float, main jet holder, 138.5 jet–not counting cost of cat food and litter
She loves being in the garage on the ATV
Joined
·
33 Posts
Hey guys, I haven't been able to get to the quad with the snow and my son wanting to play and next is the super bowl. Probably won't get to it until tomorrow or Tuesday after work. That rubber plug near the main jet, what is it for and is it in the carb when re-assembled? I see it in one picture of my manual but all other pictures it's not there plus there is no mention of it. Anyone know?
1 - 20 of 55 Posts
