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Discussion Starter · #1 ·
Something seems wrong…
I have a 1986 Honda trx350 fourtrax and I can’t get it to idle. The carb is fully deep cleaned and a new carb kit was installed. The timing is on spec, the valve are on spec, the exhaust has no leaks, the carb has no leaks, There is nothing missing from inside the carb and all the o rings and washers are properly placed with no stacks. I have a feeling it’s the choke cable(I know it has an enrichment valve but In the manual it is labeled as a choke cable so I’m calling it a choke cable please don’t correct me on this I’ve heard it a million times.) but the reason I think it’s the choke cable is because the cable itself seems too short? the leaver is pushed fully to the closed position and this is all the space I get? It doesn’t seem like enough space to function. Aswell in everyone’s videos I’ve seen it looked like there’s has more space then mine, the cable is seated where it shows in the manual and there’s nothing pushing it away from where it should be and nothing crimping the cable either.And yes I know the valve is worn to shit it’s been replaced since that picture was taken. Here’s what I mean, pay attention to how close it’s sitting to the boot
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I guess what I’m asking could it be frozen up causing a 24/7 bypass? Is there anything I’m over looking? And is there any way I can just eliminate it completely? I don’t do any cold riding or anything like that I just wanna hit the trails and look at the scenery. Any info would be greatly appreciated
 

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It doesn’t look too short but is that retracted or extended? The valve is retracted with choke on, and seated with choke cable extended.

are you having problems starting it or after it’s warm?
If problem is when warm then maybe cable is too short—take the valve off the cable end and let the valve seat in the bore. you can easily take it back out with some needle nose pliers. Then for cold start, you will have to manually choke the air at the airbox with your hand
Try it see if helps
 

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Discussion Starter · #3 ·
It doesn’t look too short but is that retracted or extended? The valve is retracted with choke on, and seated with choke cable extended.

are you having problems starting it or after it’s warm?
If problem is when warm then maybe cable is too short—take the valve off the cable end and let the valve seat in the bore. you can easily take it back out with some needle nose pliers. Then for cold start, you will have to manually choke the air at the airbox with your hand
Try it see if helps
That’s how it is with the choke in the off position, and it doesn’t start with the push of a button like there supposed to I have to hold the throttle down slightly to keep it running but I feel like that could be too much choke maybe? Since it’s extremely seized and even with it off the bike and vice grips on the end it’s hard to move so I think it sits way to high up to function and can’t be pushed back into place, but I will try that tomorrow. Thank you for the advice! If it does work with it just sitting in the bore would it be safe for me to sit something like a bushing or whatever just under the nut so it stays down and seals? Or could that affect performance? As I said I don’t really ride when it’s not nice outside so if all I need to do to start it easily I can choke it with my hand in the airbox that’d be fine by me I just don’t wanna cause damage to anything of course
 

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Yeah the cable sounds like it no good—unless you soak it in engine oil and somehow get it to break free.
The cable sells separately from the valve, which comes with a new nut assembly. You say you got a new valve?
just disconnect the valve from the cable end. Remove the spring and store it somewhere.
Use only the nut to keep the valve in place. It shouldn’t move as the valve weight and throttle vacuum will keep it in seated.
 

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Discussion Starter · #5 ·
Yeah the cable sounds like it no good—unless you soak it in engine oil and somehow get it to break free.
The cable sells separately from the valve, which comes with a new nut assembly. You say you got a new valve?
just disconnect the valve from the cable end. Remove the spring and store it somewhere.
Use only the nut to keep the valve in place. It shouldn’t move as the valve weight and throttle vacuum will keep it in seated.
So I went to do what you suggested, and I put the valve to the bottom and fired it up but the valve flew out of the bore😂 it kinda scared me but with it sitting out it idles and runs GREAT but the second I try to plug the hole it just shuts off, I’d use it like that but I’m concerned that gas might come out of the bore while I’m quadding, I could maybe just run a breather hose but I thought I’d tell the results incase you had further ideas? If I knew what was wrong I’d gladly fix it but if me and the rest of you guys on this forum can’t figure it out it should work like this I’d think
 

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Welp 😂 okay that’s what progress looks like sometimes eh? Glad you didn’t shoot yer eye out!

Maybe carb running rich—how many turns out for your pilot screw? 1 and 5/8 usually good for me not always.

Maybe carb still dirty. Wanna have another go at it? Have any pipe cleaners?
 

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Discussion Starter · #7 ·
Welp 😂 okay that’s what progress looks like sometimes eh? Glad you didn’t shoot yer eye out!

Maybe carb running rich—how many turns out for your pilot screw? 1 and 5/8 usually good for me not always.

Maybe carb still dirty. Wanna have another go at it? Have any pipe cleaners?
I have the pilot screw set out at 2 turns, I did what you said and took it all apart and cleaned it again, everything was just as clean as it was when I was finished and I put pipe cleaners down every circuit. I noticed that two of the places I was blowing air are either plugged up or don’t go anywhere, I forgot to take pictures but I had taken some before I cleaned it the first time(it’s perfectly clean now I’m just using the pictures to show the potentially plugged spots) I don’t know if there supposed to be passing air or if it’s something they had planned for a future model and hadn’t drilled out or what but they definitely don’t get any air moving through them, here’s the pics maybe you’ll know what there supposed to do
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Sounds great
Yeah i think you are about a quarter turn rich. You’re probably having a lil trouble tuning it with that stuck cable.
yup that first passage is sposda be plugged. Second is the starter passage and it has a soft plug on the bottom and a jet on the side port.
Oh I don’t know what that top side channel is i can check it out tomorrow if you want.

Just make sure to clean that enrichment circuit using a pipe cleaner like in my pic.
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Discussion Starter · #9 ·
Sounds great
Yeah i think you are about a quarter turn rich. You’re probably having a lil trouble tuning it with that stuck cable.
yup that first passage is sposda be plugged. Second is the starter passage and it has a soft plug on the bottom and a jet on the side port.
Oh I don’t know what that top side channel is i can check it out tomorrow if you want.

Just make sure to clean that enrichment circuit using a pipe cleaner like in my pic.
View attachment 152534
I turned down the pilot jet 1/4 turn, I had done the enrichment valve like that a few days ago, did you check what that top channel was leading to? I noticed this morning that the bowl wasn’t filling up with gas and with the carb all together I blew into the brass fitting that the gas line slips over just using my mouth on a small tube, I noticed it’s fairly restricted, could you check if yours is like that aswell? I was passing air through it clearly while it was apart so I don’t think it’s clogged but I thought I’d ask incase it’s an issue, I was gonna take a closer look at it but I had to go and won’t be back till tonight
 

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Discussion Starter · #11 ·
Circuit* not valve
I turned down the pilot jet 1/4 turn, I had done the enrichment valve like that a few days ago, did you check what that top channel was leading to? I noticed this morning that the bowl wasn’t filling up with gas and with the carb all together I blew into the brass fitting that the gas line slips over just using my mouth on a small tube, I noticed it’s fairly restricted, could you check if yours is like that aswell? I was passing air through it clearly while it was apart so I don’t think it’s clogged but I thought I’d ask incase it’s an issue, I was gonna take a closer look at it but I had to go and won’t be back till tonight
I just got it all back together and hooked up my booster pack, it fires right up and I adjusted the “idle adjustment screw” and it runs and idles now but it’s blowing black smoke a little bit so I guess it’s burning lean, should I be worried about that or am I okay to take it for a ride tomorrow? It’s having good throttle response and idles good most of the time, could it be burning that lean because of the idle screw? I’ll probably just take it for a short ride tomorrow to see anyways just thought I’d get other opinions
 

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Sorry never got the carb out. Sounds like you got it running okay. The smoke could be running rich, bad valve stem seals or worn rings. Enjoy the ride. Just be careful to watch if it’s getting really hot.
When Those oil sensors get old they don’t want to turn the fan on til then engine gets on the hot side.
Have you tested the fan yet? Take the blue wire going to the oil temp sensor and ground it on the footpeg—fan should come on.
 

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Discussion Starter · #13 ·
Sorry never got the carb out. Sounds like you got it running okay. The smoke could be running rich, bad valve stem seals or worn rings. Enjoy the ride. Just be careful to watch if it’s getting really hot.
When Those oil sensors get old they don’t want to turn the fan on til then engine gets on the hot side.
Have you tested the fan yet? Take the blue wire going to the oil temp sensor and ground it on the footpeg—fan should come on.
It was smoking a fair bit when I first got it so that’d make sense but I just top up the oil every now and then and it hasn’t gotten much worse yet I think it was just rusty because it had been sitting outside for 10+ years before I got it😂 it has no fan unfortunately I’ve been looking for one but I’m having a hard time finding one that ships to canada for less then 200$, how hot would you say is too hot? I left it running at about half throttle in my back yard for about 20 minutes and the head was at 76°C and the bottom end was running at 38°C, the headers were at an average of 120°C and the exhaust was at 40 - 80°C, I’d think that’s fairly cold but I’m not too sure on normal temps. What would you say is high and what would you say is normal? I can keep an eye on it while I’m riding
 

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Sounds like you’re ok
There’s a chapter in back
Fan sposda come on at 100C and overheat light aBout 165C.
 
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