350x carb issue

[chasemanmusic]

Hey guys,
Been a long while since I posted, but I just got my first 350x and having some carb issues. It's an 86 w an 85 motor and 86 carb on it. Not sure if that's an issue or not. When I bought it, the throttle cable was not routed right so it would surge when turning bars and gas was over flowing from carb. But it ran and drove ok.

Guy gave me a carb kit and recommended rebuilding, so I did. I think the carb kit was for an 85 tho based on the style of the a/f screw. After rebuild it started right up and idled nice. (Did not take apart the choke assembly). No issue w throttle cable. Let it warm up took it for drive around the block. Half way through my drive it was idling high or it wouldnt idle down when I clutched/shifted. I got it home and went to kill it w the choke (kill switch not working) and when I choked it all the way it surged up and was revving wildly. I dropped the choke and tried again. Noticed that when it hit the middle position it would start to bog as expected but as soon as all the way choked it would rev again. I shut gas off and waited it out till it died. i turned gas back on and let it sit and gas was over flowing out the carb again. Another thing to note is my idle screw is backed out pretty much all the way. Bike idled at a decent rpm there, but I thought that was strange. Also, I backed the af screw out 1.25 turns as per some write up I found on here for the 86 carb.

So, where do y'all recommend I go from here? Should I buy the correct carb kit and rebuild? Should I tear it down again and open up/clean the choke assembly? Or should I mess w adjusting the a/f screw. I made note of the af screw position when I took it apart. It was 2.25 screws out I believe. Or should I bail on this carb and try another. Any help is appreciated. Thank you!

[wonderboy]

The overflowing fuel is due to your float not working properly. Lots of things could be going on:
- The needle could be getting hung up
- The seat might not be clean or has a nick/burr
- The float may not be floating (hole, bent, too much crud stuck making it heavy).

All your other settings will be out of whack if your fuel level in the bowl is off.

Did you save your old parts? The reason I ask is that I've seen incorrect float needles before that are too short. Compare your old float needle with the new one. Also, to check your float height. To do this, hold the carb in your hand with the float bowl removed. Hold the carb sideways so that you can carefully move the float and check when it just starts pushing on the spring loaded button on the float needle. When it just starts to push on the needle, the float should be parallel with the float bowl mounting surface.

[Shawn Powell]

Toss your factory carb and buy a 400ex carb. New there 150$ and used even cheaper. You'll need a throttle a cable also but fairly cheap. Great upgrade on even a stock to mild bike. Larger, accelerator pump , easy to find parts etc. starts easier runs harder fits with very little struggle.


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[chasemanmusic]

Thanks for the responses guys. I'll tear it down another time and try wonderboy's suggestions first. If I can get her to run right I'll take it for now. I heard the 400ex carb is a nice upgrade so I'll definitely do that at some point, especially if the stocker won't work.

As far as the 400ex carb, does it work out of the box? Or do I have to rejet it or something?

[Shawn Powell]

Thanks for the responses guys. I'll tear it down another time and try wonderboy's suggestions first. If I can get her to run right I'll take it for now. I heard the 400ex carb is a nice upgrade so I'll definitely do that at some point, especially if the stocker won't work.

As far as the 400ex carb, does it work out of the box? Or do I have to rejet it or something?

Hard to tell. My motor is very mild. Once over wiseco. Mild porting full exhaust stock cam. I only went up 2 jet size and I think two pilots. I know my mAin is a 148. Forgot the pilot. I think the 400ex stuffs a lot more fuel because of the accelerator pump so the jets don't have to be huge. I run the air box lid also so I might be able to get one more main .... but I would start with one size over what you have in your factory carb (OEM was 138 so maybe a 142...) unless you have more mods. But it's a good place to start.


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[chasemanmusic]

Ok i need to brush up on jet size terminology, etc.

i dont know anything about the internals on the trike as far as mods. I do know it has a dg pipe, not sure if full, looks like only dg silencer and stock header as the header is not chrome like the silencer. Also airbox has holes drilled in the lid, which im not sure if thats considered a mod or not.


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[chasemanmusic]

I https://uploads.tapatalk-cdn.com/20170524/c2cdadd041dc20abf857ba50e0abc52d.jpg

Figured id post a pic


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[chasemanmusic]

https://uploads.tapatalk-cdn.com/20170524/e9c305183ea436ed521ffe6dfa793f7a.jpg


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[350for350]

Just use the jets from the 350x carb in the 400ex carb. That's what I did and everything works great. I can't remember now if the 350x carb has a round slide or not. If it does, did you accidentally put it back in 180 degrees off? It will idle high and won't idle slower at all. If it's doing this, then it already has extra air going through the carb. Choking it would add more fuel and then could certainly run faster. I'd check that first. Not trying to turn you off of the 400ex carb swap, but my suggestion won't cost anything but time.

[chasemanmusic]

Wow good point. Yes its round but i didnt notice a difference in which way it would go like the carbs on my 200x and 185. Those have a clear direction but i think you might be right.

Im hoping to have time to tear it down tonight and test again. Ill follow up tomorrow.

Thanks again to you all.


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[chasemanmusic]

Yea the throttle thing is symmetric either way you put it. Main needle looks really close in size. Different numbers on it tho


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[chasemanmusic]

Would an air leak cause behavior like that? Plug looked alright.


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[350for350]

It possibly could. That would be worth a look, too. Now my story about throttle cable routing. I had an independent shop put a new throttle cable on my 350x in 2003. The next weekend, a friend and I went out of state for a weekend ride. Everything was fine until I climbed a hill with a sharp left hand turn at the top. I came up in second gear, let off the throttle, and turned the bars left. Unfortunately, the trike revved up hard and we both went straight, hit the berm at the turn and it flipped over on top of me. With the 350x carb, the only time the stupid thing would idle was when it was upside down on top of me. This was one of the two times it idled, still in gear. Since we were riding sand trails, I was running my old Blackwater tires that I use in the sand as "semi paddles". So the right one was chewing up my right leg and I had the hardest time reaching the kill switch. After I shut it off, pulled myself out from under it, and got it back down the hill, of course I had to kick it for a LONG time to start up again. I figured out that it revved to about half throttle when turning hard to the left. I took it back to the guy the next week. He told me that his assistant had out the new cable on, but there was no was it could be on there wrong because there is only one way to route it. I was not happy with that answer. I pulled the tank off myself and sure enough, the cable was routed wrong. There was even a mark on the under tank insulation that showed the right way to run the cable. After I put it back on the right way, I never had that problem again. I also never went back to that guy again!

[chasemanmusic]

I got the carb straightened out i think. I found the rubber plug ended up falling out of that one jet. I removed it. I also found the third time i rebuilt it that I didn't tighten the jets enough and one fell out in the bowl! Never had that happen. So i buttoned it back up and no more over flow. But it was still racing and found it was my throttle cable routing that was holding the idle open. After messing w that for a while the idle adjustment works as it should.

So i took it out today and it rode nice. Good power, but a little popping from exhaust when letting off throttle. It has a full dg pipe. Is that normal? Also the air box lid is drilled out.

I pulled the plug after it cooled down and found it was a little white looking (lean). So should i jet it up? Or can i simply adjust the idle/air screw to allow more fuel?


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[chasemanmusic]

Oh and one other question: the butterfly and the slide sync- are they supposed to operate in sync? As it is now the butterfly moves then the slide engages


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[Shawn Powell]

I would bump it one mIne jet and maybe a quarter turn past factory on your idle fuel screw. If it still pops up your air fuel jet one size and repeat.


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[350for350]

You could also try fine tuning with the clip position on your needle. By the way, since nobody answered, yes, holes in the airbox lid is a modification. It lets more air into the stock airbox.

[chasemanmusic]

Thanks guys. I'll start w a quarter turn out on the air fuel screw then will try bumping the main jet up one notch and see what happens. I also found a good write up on here for carb rebuilds that addresses the syncing of the butterfly and slide


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[chasemanmusic]

Is it unscrew or screw in for lean/rich?


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[6spdls1z28]

Unscrew to richen

[jb2wheels]

On topic but late:
THIS THREAD (http://www.3wheelerworld.com/showthread.php/161746-ES-SX-350X-Carb-rebuild-Tutoral) is a must read for 350X carb Q&A.

Off topic:
Size and brand of back tires?
What can I say? I like the dimple knobbies.

[Shawn Powell]

On topic but late:
THIS THREAD (http://www.3wheelerworld.com/showthread.php/161746-ES-SX-350X-Carb-rebuild-Tutoral) is a must read for 350X carb Q&A.

Off topic:
Size and brand of back tires?
What can I say? I like the dimple knobbies.

I went with the Kenda scorpions 20 10 9. Nice and light due to being two ply. Seem tough enough. Grip and slide nice. There a bit small though. They measure 19 x 9.5 fully aired on a 8" wide rim. I had ITP Ct holeshots. They were 6 ply and skipped the rear end all over but griped great and wore like iron.


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[jb2wheels]

Good info about the Scorps. Not my favorite. I like the tires in the pics - used to be Armstrong knobbies like that but times have changed.

[Shawn Powell]

Good info about the Scorps. Not my favorite. I like the tires in the pics - used to be Armstrong knobbies like that but times have changed.

Yeah what you will find is everything is made now for the 450 and larger sport quads and is at a minimum 4ply. The trikes are just to light imo for this. I also had run a set of Duro mud and sands. 22 11 9. There two ply have that old school chevron tractor pattern. Don't slide to well. Also big. Like 23" almost. I think the Kenda is the most appropriate for the era. I did see a simple knobby Chang shin correct size and ply. But they are a cheaper tire. Both in price and quality. Good luck https://uploads.tapatalk-cdn.com/20170607/9a8477171f879e7c2ea3d9aba9652614.jpg
Kenda
https://uploads.tapatalk-cdn.com/20170607/2265f329fea609de3922b7ac45f82505.jpg
Duro
https://uploads.tapatalk-cdn.com/20170607/efb3835b3da5008f047cee0d147f2bd2.jpg
ITP holeshots


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[chasemanmusic]

Tires are Carlisle turf tamer 20 11 9s. At first I didn't care for the look of the old knobbys, but after a while of looking at it and riding it I love em. Good bite on accel and easy to kick out in slides.

As far as the carb, I jetted up to 142 and plug still looks a little lean. I also have the butterflies in sync. I lowered the needle clip to make it more rich but haven't had time to do any field testing. Essentially got it idling nice and throttle response close w air screw. Hoping to have time for some testing after work today.


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[chasemanmusic]

If still lean I'll adjust the needle clip to richest setting and check. After that not sure where to turn.


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[Dirtcrasher]

Needles usually end up 1 clip either up or down from the center clip,

If you have to go more than that you may want to bump up your main jet.

[chasemanmusic]

https://uploads.tapatalk-cdn.com/20170612/551986f8046f30be4e4f7de3caf13e58.jpghttps://uploads.tapatalk-cdn.com/20170612/a72e27549f3d7651c4c30331040ff3be.jpghttps://uploads.tapatalk-cdn.com/20170612/ec8e91113489d60776087f0775d7fdd1.jpg

So the base of plug looks dark but the end is still light in color. Its running good. I could turn air screw in another quarter and keep checking. Or should i go ahead and bump the main up more?


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[Shawn Powell]

That's a bit lean for my flavor. I'd try one more on the main(148 I think is next) and see what happens. Keep in mind your air screw only controls idle and the needle on controls mid range. Wide open the needle up or down makes no difference. One up might end up being to rich but a fouled plug is cheap and pistons aren't.


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[Ranvier]

Is that a plug chop or after mixed riding? How's the power from idle to wot? I would just run that if good power and throttle response....

[350for350]

All you can do is keep going and keep up the field testing. Even when it's running right, still do the field testing. That's the best part! You never know, it may run differently after you fill the tank with gas, better field test it! Works for oil changes too.

[chasemanmusic]

That is after mixed riding. Essentially around my block. A couple wots through the gears, some decels, and some cruising at low rpm. Pull in my drive way, kill it and pull plug. I choke it to kill it because kill switch doesn't work. I've tested it and connectivity everywhere. Can't see why it's not working. For jetting up the main can I simply put any 148 for a keihin on there or do I need to order it for exactly this carb?

The power seems good from idle to wot. I did feel it was holding back a touch once at wot but thought it was just not warmed up enough. Maybe it is the main being too small.


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[chasemanmusic]

Grabbed 148 main at local atv shop. Installing tonight.


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[chasemanmusic]

148 is in. Set needle back to middle. Started messing w air/fuel screw to help throttle response. Kept screwing out. Got a little better but screwed it pretty far out. Ran out of time. Pulled plug quick and it's wet. So at least i have a rich condition. Gona mess w that screw a little more tomorrow if no improvement going to drop the needle/raise the clip a notch.


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[Shawn Powell]

I'd keep the screw somewhere between 2 and 2.5 turns. Remember it only controls idle. Anymore than that I would bump my pilot if it's still lean there. ( popping when you turn it off , hot headers etc. )


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[chasemanmusic]

I think it is really close now. Set it to 2-2.5 out and was still a bit lean looking but was better. So i decided to richen the needle down a notch and as i was reassembing i noticed a discoloration on the cap of throttle which i think was an air leak. So i tightened that up good took it for another ride. Exhaust popping is gone on decelerating, idles smooth, good throttle response, and pulls hard at wot. Plug looks better. Oh and header is much cooler. Before i couldnt even adjust idle/ get near that pipe without feeling like my hand was gona burn.

Ill post 2 pics below. First before air leak fixed second after ride around block. I really need to do more legit field testing, you think its safe to do a more extended ride?


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[chasemanmusic]

https://uploads.tapatalk-cdn.com/20170615/3477f6c92af40b1c38f505cccca1c24d.jpghttps://uploads.tapatalk-cdn.com/20170615/a94fcb0929226770822cf710630e0e6e.jpg


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[Shawn Powell]

Obviously I'm not a doctor. My wife does have a nurse outfit. But that's a different conversation. Yeah I think your good to ride have fun. Bring an extra plug just in case and the tools to change it but looks good to me.


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[chasemanmusic]

Lol Thanks Shawn and to everyone else who chimed in here.


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[Dirtcrasher]

The EASIEST way to diagnose em all:

Take The airbox lid/panel/cover off.

A) Runs better, you were rich and needed more air.

B) Runs worse, you were already lean and now you gave it even more air.

Lean motors really rip until a meltdown :lol: they're crisp!

Pulling the choke on and/or it running better with the choke on always means you were lean.

And rich jetting falls flat on it's face, it's blubbery, boggy and will have an ugly sparkplug.

An oil fouled sprarkplug is from a 2 stroke running Castrol at 12:1 :D


Only make one jetting change at a time and write down numbers and running condition