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Discussion Starter #1
Hey dudes! My name is Jacob, and last night I bought a 31-year old Honda Quad!! 1986 Honda Fourtrax 350, I attached a picture. Cosmetically, it's in pretty good shape-- only one plastic crack, no oil leaks I can see, custom footwell rests.

It ran a couple weeks ago when I first went to check it out. Needed a bit of starter fluid in the airbox, but it idled solidly after that. It revved pretty high, smoked a little, and when I let off the throttle it slowed and died. No troubleshooting done on that yet, but the moral of the story is IT RUNS! Couldn't get it started last night to get it on the trailer so we had to push it, but the battery was almost dead so no surprise there.

It needs a fuel tank-- the one that was on it has a golfball-sized hole! :crying: man, those things are expensive. Other than that and some other TLC, I should have it running pretty soon. I'm a decent shadetree mechanic, and I've got a '72 Honda CL350 bike so I'm pretty familiar with these old beasts.

Looking forward to hanging out on this site! Seems like there's lots of good info here, I've already got a service manual and a few ideas on how to fix my dying-after-rev issue.
 

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Nice ole gal ya brought home with ya there!

Have you looked into a plastic gas tank for it yet? They are pricey... but better than paying a ridiculous price for a used and rusty OEM tank! I think Clarke makes them... maybe find them on Amazon or the fLeebay.

Welcome to the forums!
 

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Wow, another classic tank that's about three or four in just a couple days! Impressive , welcome t the forums from mid TN, cman i still say this is odd lol but I'm likin t!
 
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Wow, another classic tank that's about three or four in just a couple days! Impressive , welcome t the forums from mid TN, cman i still say this is odd lol but I'm likin t!
I been thinkin' its odd too. Must have been a dozen showed up in the last couple weeks or so! I'm afear'd one day I'll log in and see:

all your trx350 are belong to us

...on every post! LMAO
 

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Yeah i agree, i noticed a honda box on the front rack, I've only seen one (on eBay) sold for $395 @jacob hang on that! And if you could post some close up pics for us.....
 
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Very nice!

Several things can cause rough running, good for you to start with making sure fuel system is good. A good battery is essential for good ignition. Best thing is to get the service manual and catch the ol girl up on maintenance

Cosmetically I noticed the headlight riser is installed backward ? Swap it around and the pin will fit perfectly into the bracket
 

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The cmp foot gaurd mod is nice, stock they have no bottom plate
 
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Discussion Starter #11 (Edited)
Thanks for all the replies!

I'm ready to pull the trigger on a plastic gas tank-- my only concern is how hot it will get, sitting right there next to the muffler shield. I was thinking of maybe putting some fiberglass material or other heat barrier between the shield and the tank. Don't want that $300 to melt away on a hot run!

@jay10 I've looked and looked for that box, and it is apparently incredibly rare. The seller had a guy offer $150 plus shipping for just the box, and in fact when I bought it I wasn't expecting it to come with the box, since the seller and I had discussed him keeping it. The seller let it stay on the bike though, so at least for now I'm going to keep it where it is.

I was able to mess around with it a little last night. It started up easy, idled for around 3 minutes, then died. I could restart it immediately, but it wouldn't idle solidly. I could give it some throttle and it would stay revved, but would die when I let off. I have not checked voltage to my fuel pump, but I'm betting it's the cutoff sensor causing problems. If so, I'll just wire an on/off switch, or maybe wire in a relay somewhere. My other thought is a battery/voltage problem-- after I was done starting it for the night, the battery took a few hours to charge back up. Supposedly the battery is 2 years old and mostly un-cycled, but that was third-hand information.

Pulled the spark plug, it was very carbon fouled <rich>. Replaced it, but no difference in operation. Between replacements, I did measure compression at 150psi warm! Very good news there, I won't have to worry about new rings anytime soon.

Rear brake cable is seized up good. I didn't mess with that much, and I haven't read my manual yet (!), but I'm thinking I need to loosen it from the wheel so that I can get it disconnected at the lever to lube it. It kind of seems like I need a specialty tool to loosen it from the wheel, but before I mess with that I'm going to read the manual.

Pics attached!
 

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Welcome to the forum.

I've got a 350 in the yard that I'm going to cannibalize for parts to fix another one. If you're interested I can pull the tank and see what kind of shape it's in.

I'm in East Arkansas close to Helena.
 

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The new plastic tank will be fine with the stock heat shield, no worries. Fuel in the tank is a heatsink...

It sounds like the choke plunger needs a new seal installed on it since it is running rich and stalling once it warms up a bit. Choke cable may be holding it open too... due to its age I would clean the carb good and put new seals, o-rings & bowl gasket on it and use the FSM to set the carb up in spec. I bought a cheap china kit to get those small rubber parts for my 87, then threw the rest of the useless kit away. Reuse your float needle... its probably ok... the china made ones are junk.

The battery may be fine... it is used for starting and powering lights and accessories. The 86 350s have an AC-CDI ignition, so the ignition is not affected by a dead battery. You may want to check the charging system though, but thats pretty easy too.

The rear brake cable has a wingnut adjuster in the lever on the rear brake backer. Lube those threads and use some pliers on the wingnut if you need too... Those cables are cheap on the fLeebay used... if yours is seized bad I'd just replace it.

Glad you are fixing it up!
 

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@clofan i would hang onto it as well, on the Cambridge cmp foot gaurd, the mod is nice, but.... The way it is now want let you have a rear right hand foot brake peg, needs to be trimmed some with a torch or take a angle hand grind with a cutter wheel, and i would do the same on the left, looks like it would be very uncomfortable to shift with shift peg splined up that high, and the reason for the brake seems the shorter foot cable works better then the longer left hand handle bar just food for thought :) oh! And i would talk to @Jeepwm69 for the gas tank, and i have nothing against a plastic tank.....
 

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Discussion Starter #15 (Edited)
Ah, so there's two ways to engage the back break eh? Makes sense now, I was wondering why I had two cables coming out. The PO thought of that, and it looks like there was a brake pedal at one time welded, but has since been removed. I could probably fabricate something to replace that, and make it bolt-on so that I can take the pedal top off if needed.

The footwells are really well done and bolt-on. On the shifter side, he put an extension going the other way so you can push down with your heel to shift up, or down with your toe to shift down. I've attached a pic to show you what I mean.


One of the POs was an aircraft mechanic, and you can tell he took care of this machine.
 

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Yup, and looks like the foot brake arm is there right below the oem foot rest peg only I'd do is make the opening just a bit larger, there well modded for sure!
 

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This is the animal....
 

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Nice! If works good ? That side i wouldn't touch fellow has talent....
 
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I also noticed the temporary fuel tank you have hooked up has what looks like, a tight fitting lid on it. If that tank is insufficiently vented that could be your stalling problem as well. I would set the carb up completely like the FSM recommends, regardless. Its an old machine and will need to be brought back up to specs everywhere you look. Every cable will need to be readjusted as well. Valve adjustment and decomp cable should be looked at soon too.

You'll love it I'm sure!
 

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Discussion Starter #20
You know, you're right-- could be just about anything! Ha. Instead of trying to track down the problem, a full tuneup is in order I think.

-Oil+filter Change
-Carb clean / inspection
-Valve adjustment

What else? I'll probably do differential fluids and master cylinder bleed/fill once I get the engine problems knocked out.

Oh, and not pictured is the seat with a 1.5" tear in the back corner, all the plastics that go on the back end, the rear hoop, and the rear cargo rack. Guess how much I paid for this thing? $400 You want to talk about a steal...!
 
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