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Hey guys. I'm at my wits end with this thing. The engine starts fine, runs for about 15 to 20 seconds, then kills. This happens over and over again. The battery is fully charged. I've replaced the cdi box... yes the expensive one, replaced the stator, the pulse generator, fuel pump, fuel filter, rebuilt the carb, new and correct plug, fresh oil and filter. Everything looks to be in place. I also took the 2 peep holes off the left cover and made sure the flywheel is lining up with the notch. I don't know what else to do. Please tell me this is an easy fix. I'm tired of dumping money and time into this old girl. She once ran like a top when the cdi went out. Replaced the cdi and it ran great again then one day it just stopped altogether. Any help would be appreciated. Thanks in advance.
 

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You have the manual? Download the service manual and check parts links in my signature block below.
Are you only buying OEM parts?
Does it get fire at the spark plug after it quits?
If so, do the fuel flow test in the book. Maybe fuel starvation or bad cut relay.
 

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Discussion Starter #3
You have the manual? Download the service manual and check parts links in my signature block below.
Are you only buying OEM parts?
Does it get fire at the spark plug after it quits?
If so, do the fuel flow test in the book. Maybe fuel starvation or bad cut relay.
Thanks for your reply Goober. I do have the manual printed in a binder. There is a spark and I've done the flow test. I even replaced the fuel pump. What is the fuel cut relay? Is that the fuel pump relay?
 

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Discussion Starter #5
Yup.
OEM parts only?
The stator, pulse generator, and the cdi are all OEM. The fuel filter and pump are aftermarket. I did keep the old pump just in case. The fuel filter had to be the original because when I took it off, it was super dirty.
 

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Discussion Starter #6
Yup.
OEM parts only?
I did do the test with the relay the manual suggested with the jumper on the harness side and it worked the way it should. I'm going to put the battery on a trickle charge today to make certain it's fully charged. I assumed it was because the bike has no problems starting. I can't help but wonder why Honda put the fuel tank and the air filter in opposite positions on the bike. I've owned the 86 200x ATC, 86 350x ATC and the 86 TRX 250R and the fuel tank and air filter were in their traditional spots. Why is this one different? I know it's better for snorkeling and stuff like that, but even that stuff isn't recommended by Honda (and I would never do that with any of my machines... just asking for trouble). Thanks again for your help.
 

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I had the same issue with my '86 350 and think it was a lack of fuel in the carb, caused by something getting into my cheap amazon POS I put in there. After a rebuild on the OG honda carb it ran better than I've ever seen it run. Might have been a float bowl issue? I was chasing electrical issues that weren't there, replaced the fuel pump, checked compression, and the carb ended up being my fix.

Best of luck...
 

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If you have fuel and spark and still wont fire then I would check/set the valves to ensure one鈥檚 not sticking open or maybe the cam chain jumped time
 

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Discussion Starter #9
I had the same issue with my '86 350 and think it was a lack of fuel in the carb, caused by something getting into my cheap amazon POS I put in there. After a rebuild on the OG honda carb it ran better than I've ever seen it run. Might have been a float bowl issue? I was chasing electrical issues that weren't there, replaced the fuel pump, checked compression, and the carb ended up being my fix.

Best of luck...
Thanks bro. That's my next attempt. I've been chasing electrical issues too. I rebuild the OEM carb when I first got it, but after replacing the fuel filter and seeing all the junk that came out, I'm thinking I need to clean out the carb. Thanks for the help! It appears we've faced the same issue with this old girl!
 

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Will it sputter when you spray starter fluid into the intake? This might help confirm fuel starvation.

hows your tank look? Rusty and solids floating on bottom? Mine was horrible scaley. I performed a vinegar descaling and cleaned the suction lines; rebuilt the petcock.

150981
 

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Discussion Starter #11
Will it sputter when you spray starter fluid into the intake? This might help confirm fuel starvation.

hows your tank look? Rusty and solids floating on bottom? Mine was horrible scaley. I performed a vinegar descaling and cleaned the suction lines; rebuilt the petcock.

View attachment 150981
I
Will it sputter when you spray starter fluid into the intake? This might help confirm fuel starvation.

hows your tank look? Rusty and solids floating on bottom? Mine was horrible scaley. I performed a vinegar descaling and cleaned the suction lines; rebuilt the petcock.

View attachment 150981
It will start and run for about 15 seconds. It will continue to do the same thing every time. The fuel tank is dirty. I'll start there and clean the carb as well. Whether that's the problem or not, it certainly won't hurt and needs to be done.
 

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Fifteen seconds is a long time. I suspect fuel starvation due to sediment in fuel tank and suction lines.Fuel tank has a drain bolt ya know?

Maybe also related to your aftermarket pump. I鈥檇 buy OEM yes $150.

I attached a link to my tank cleaning thread. I cleaned my tank using 2 gallons of cleaning vinegar from Walmart and a pound of BBs. Rolled it around in my cement mixer for 3 hours.

Take off your petcock. inspect to see that the seal hasn鈥檛 slipped and is blocking flow. I rebuilt all my petcocks.

Use about a foot of a old brake cable and make sure the 2 suction lines
are clear.

 

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Discussion Starter #13
Fifteen seconds is a long time. I suspect fuel starvation due to sediment in fuel tank and suction lines.Fuel tank has a drain bolt ya know?

Maybe also related to your aftermarket pump. I鈥檇 buy OEM yes $150.

I attached a link to my tank cleaning thread. I cleaned my tank using 2 gallons of cleaning vinegar from Walmart and a pound of BBs. Rolled it around in my cement mixer for 3 hours.

Take off your petcock. inspect to see that the seal hasn鈥檛 slipped and is blocking flow. I rebuilt all my petcocks.

Use about a foot of a old brake cable and make sure the 2 suction lines
are clear.

I'm going to start on this today. I kept the original pump. I might just run some clear gas through it until it comes out clear then reinstall it. Thanks for all your help. I'll keep y'all posted.
 

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you have to remove two nuts from the bottom of the rear bumper to drop the fuel tank guard. Then use a socket wrench to loosen the tank drain plug. Have a bucket handy!

You can also use a piece of weedwacker line to make sure the suction lines are clear.
 

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Discussion Starter #15
you have to remove two nuts from the bottom of the rear bumper to drop the fuel tank guard. Then use a socket wrench to loosen the tank drain plug. Have a bucket handy!

You can also use a piece of weedwacker line to make sure the suction lines are clear.
I just came in from removing the tank and soaking/ sloshing the tank. I used apple cider vinegar and some pea gravel. I'm going to let that soak for a couple of days. I'm going to empty the tank and rinse with water and baking soda on Thursday. Funny you should mention the weedwacker string, because that's exactly what I used! I kept working the string until I couldn't push it any further. I did that until the string came out clean. I used compressed air to run through the petcock. Being it's riveted, I want to make sure I have some small bolt and nut combos to assemble it back. So far, the vinegar looks dull red and gritty. I guess it's doing its job! Please let me know after reading this if I'm going about this the right way and thanks again for all your help! I'd like to have this girl up and running before trapping season!!!
 

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Dont let the cap rubber soak in vinegar.

i used BBs because they鈥檙e denser and magnetic. Other materials might get hung up in the tank.

yeah soak it, slosh it around, let it dissolve the rust. You can rinse it with plain water but you鈥檒l get flash rust right away. That鈥檚 OK you can do a second cleaning. do the final rinse with a high pH solution and dry immediately with a hair dryer.

now, you鈥檒l have some bicarb residue in there. Do three small volume rinses with fuel an dump or filter it. prevent those additional solids from clogging your new filter.

here鈥檚 my petcock thread
 

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Discussion Starter #18
Oh the weedwacker string was @Lowall idea lols
Hey Goober. The amount of crud that came out the tank today was crazy! I took apart the carb. In doing so, I found out the slide was stuck in the down position. Could this have been the cause of my bike acting like it was? No doubt the crud from the fuel tank made it stuck like it was. Anyway, I took it all apart, cleaned out all the jets and lubed all the moving parts. Now the carb works like it should. I decided to give the tank another shot of vinegar since so much crud came out today. I'll clean it out again tomorrow. I keep you posted when I get it back together tomorrow. Thanks again for all your help.
 

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Three things with this QA03A carb.
1) The choke (enrichment circuit) likes to trap dirt. Get some pipe cleaners, bamboo handled cotton swabs and dental brushes. Berryman Chemtool is my go to cleaner.
2) the enrichment valve may need replacing鈥攊f you get it to start without the choke the valve is probably worn enough to cause richness problems when warm. How鈥檚 the plug look? This could cause your problem too
3. ThIs carbs is OLD now and likely needs a rebuild I rebuild my carbs using Shindy rebuild kits. Problem is they don鈥檛 include the starter jet passage plug鈥攄o you have it? It鈥檚 shown in this RH carb but not in the left.
150995
 

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Discussion Starter #20
Three things with this QA03A carb.
1) The choke (enrichment circuit) likes to trap dirt. Get some pipe cleaners, bamboo handled cotton swabs and dental brushes. Berryman Chemtool is my go to cleaner.
2) the enrichment valve may need replacing鈥攊f you get it to start without the choke the valve is probably worn enough to cause richness problems when warm. How鈥檚 the plug look? This could cause your problem too
3. ThIs carbs is OLD now and likely needs a rebuild I rebuild my carbs using Shindy rebuild kits. Problem is they don鈥檛 include the starter jet passage plug鈥攄o you have it? It鈥檚 shown in this RH carb but not in the left. View attachment 150995
To say I'm done with this machine would be an understatement. After getting the tank really clean and dry. I put it all back together with the rebulid OEM carb. Lubed up the parts that were froze up and got them working properly. Added new fuel lines and a new fuel filter. Tried turning it over and saw the fuel flowing in the clear lines. Then she fired right up! ....But killed a few soconds. It would do the same thing after that until finally it wouldn't start at all. Checked the plug which was a little dirty. Cleaned it up and tested the spark. Now no spark! This thing is freaking cursed! 500 bucks. Come get it
 
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