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Hello. I'm new to the thread and joined to see if anyone could offer me some of their input on this issue. This problem has plagued me with this bike for years now. It is a great running machine, when it is willing to run. I have three of these old Hondas, an '86 TRX350, an '87 TRX350, and my "87 TRX350D. Here is the problem that I have been dealing with for the past 6 years. On occasions, the Honda starts fine. Sometimes it will run with no problems at all and I can ride all day without a single issue. On other occasions, it throws these weird temper tantrums where it will partially start, partially run, then die. I will then have to mess with it for a while, when out of the blue, it will start to run normally. Sometimes it will run fine but sometimes it will die while riding it and I have to repeat the process. I have been dealing with the issue for years now. About a year ago I parked it because it needed a front wheel bearing. It sat for about 5 months as I couldn't find the time to do it. Went to start it and I couldn't get the pump to pull fuel. Figured maybe the shutoff on the tank was plugged, and put it off until I had the time to delve into it further. A few weeks ago I found the time to mess with it, pulled the lines off the pump, sucked on them, got the pump to pull, and well ah. Problem solved. Ran great for a couple days, and I got to thinking that maybe that was the problem all along, until it decided to start throwing its fits again. I noticed that sometimes when it throws it's fits, fuel runs out of the overflow hose. Now I'm thinking it could be a carb issue, but all these years I've thought it was electrical. I found this YouTube video and this gentleman appeared to be having the same problem, and what mine is doing is very similar to this. Here is the link if you would like to see what I am trying to describe:


He apparently traced it to being old fuel but I suspect that wasn't the case and I know that's not the case for me.


Any suggestions and advice on this matter will be greatly appreciated!
Thanks again,
-Morgan
 

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Hello, welcome to the forums!

It sounds like you may have a rusty fuel tank on your 350D! If you have a small mirror & a flashlight you can look around inside the tank for rust that may be flaking off and being pumped out through the fuel pump and into the carb. If so, you'll need to remove the tank, the fuel pump & the carb and clean all of those thoroughly. Replace the fuel filter.

After you get the tank cleaned out you can inspect inside it again and decide whether it is fit to be derusted or is beyond saving... If the steel is still relatively thick you can derust the tank with some distilled white vinegar & salt mix and a couple hands full of aggregate of some sort.... ask about that process later if you decide to derust your tank... lots of help from the guys here who have done that.

Let us know what you find if you can...?
 

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Likely obstruction in fuel delivery or bad fuel pump--that ticking means fuel is not being pumped. Do the fuel pump flow test. Just because it's ticking doesn't mean it's pumping.

You might also have a crimp or air in the fuel line making it lose suction.

Like retro Said maybe rusty in gas tank? Check for obstruction in gas cap. Two little fuel lines running to petcock--pipe cleaners or a very slender nylon bristled brush will clean them out. Take off the petcock. Look in the back two holes--has the petcock disk slipped and blocking the fuel passages? Any junk in there? Picture of petcock and disk--disk can jump off the fittings
Make sure all fuel lines clean and have good hose ends and clamps.
 

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Discussion Starter #4
Huge thanks to both of you for your replies. greatly appreciated! Retro, thanks for the welcome! I've suspected rust in the past but the inside of the fuel tank appears to be clean as a whistle. If I have time sometime this week I'll get in there with a mirror and flashlight as you suggested to inspect it better. Goober, The pump on mine always comes up to pressure within a few seconds of turning the key on. The video Link I posted Isn't mine, but mine is running very similar to the way the one is in the video, with the acception that my pump isn't clicking while trying to start it. I can hear it come up to pressure and I don't think it's a pump issue. Though I have wondered if it was possible for the pump to be pushing too much fuel, hence it running out the overflow and possibly fouling the plug out on occasions? Let me know if that sounds plausible? Haha. If I get a chance I'll take a video of mine this way it will be more accurate. Thanks guys again for your help, I really appreciate it!

-Morgan
 

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If fuel runs out of the drain hose at any time, it means the float valve is stuck open or is very worn and leaky. I figured it is rust that is sticking open your float valve... but maybe it is just dirt getting through the filter or the float valve could be wearing out.

I would pull the carb off and disassemble it for a thorough cleaning. You'll see the condition of the float valve and the float then, and will know whether either of those are getting bad or not. Reassemble the carb and set it up exactly as the service manual recommends, word-for-word.

Hopefully your float & valve are still good, cause those aren't available to purchase anymore as far as I know.

Keep us posted...
 

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You could also check the fuel cutoff relay. If the relay is malfunctioning could be related

I recently bought a new float it was $38
 

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Discussion Starter #7
Thanks guys again for the advice. Tomorrow I have some free time so I'm gonna fiddle around with it and check the tank and fuel cutoff relay. If everything appears normal, then I plan on tearing into the carburetor. I'll keep you guys posted. Thanks!
 

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i would take off the feed line to the carb and lightly run a small cotton swab into the pipe--that channel leads to the float valve
 

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my .02's worth. clean and inspect the fuel tank. drain/flush all old fuel from tank, replace with fresh new fuel. NEVER assume the tank is spotless ?, even the tinniest piece of rust can cause fuel delivery problems on these old gals. from the way you say it acts up ?, bad fuel cut-off relay ?, or fuel pump going out ?. leaking carb : float needle sticking, sitting up for anymore than a month will cause this !. once everything is checked/replaced ?, worse case, c.d.i. is going out ?. invest in a carb rebuild kit, wise money spent in the long run !. shindy or moose brand is a couple good kits.
 

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It’s been a little while since I posted on this thread, Mostly because I forgot my password 😡But I Wanted to thank everyone again for their input! Haven’t been able to mess with it much for the last year, I was focused on setting up a snowplow for the other 86’ which is a pushing motherf****r! Had a plow lying around for a few years and decided to make brackets to bolt right over the footpegs and man does that thing plow good! In the next few weeks I’m going to tear that carb apart on the Foreman and do a rebuild. I’ve been thinking on it and am really hoping that will solve the problem once and for all. Planning on getting everything back up and running this season, including some Willy’s Jeeps! Should hopefully be a productive summer! I’ll keep everyone posted! Thanks again!
 

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Nice cover on that Chili Pepper Fourtrax

First thing i did was derust my tank–i found a glove and a screwdriver in there! Plus it was crusty layered up rust. Find out more how I cleaned this tank on this thread
https://www.hondaatvforums.net/forums/honda-fourtrax/125620-86-trx350-fuel-tank-borescope.html?highlight=Borescope

If your tank is relatively clean then simply remove the drain bolt and completely empty the tank. Unbolt the fuel tank guard plate from the rear bumper and it will rotate down and away to expose the tank Drain bolt.

Rebuilding the carb is so easy–the hardest part is breaking loose the screws and jets-especially the two tiny throttle piston screws. Spray them all with Deep Creep and put the carb in a freezer overnight.

You will need a Shindy rebuild kit and a starter valve. Bad valve can cause your fouled plug

your intermittent running could be related to fuel pump/relay, CDI, or fan control unit. Start by getting that fuel system reliable. Clean tank, filter, carb–the pump is likely to leak after setting up for a long time.


Download the service manual at my links here
 
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