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I bought a nice looking purple scrambler 500 for 400, it acted like the carb was clogged, but it turned out there was all sorts of problems, mostly from shitty mechanic work. The flywheel was busted, the stator was bad, it was out of time by one tooth and the chain was stretched. The cam looked brand new almost, also the decompression spring was installed wrong. Anyway i have fixed most everything and got it to run but now again i am back to the carb not working. I have rebuilt the carb using an ebay rebuild kit, and already had to re install the old float needle since the new one just would not seal. Now it's really hard to start, when it does start it will idle fine but will not take gas , so i removed the air box and filter again and adjusted the choke completely in so that can't be the problem, but what it is doing is the slide will not raise up, i can reach in and push the slide up with my fingers and it takes gas really good, but it just wont work by itself and also it is making huge amounts of carbon, obviously it is running rich , i am not sure if its because the slide wont open or the jets in my rebuild kit are all wrong, but first things first , what could be making the vacuum slide not operate? I can't find any leaks , my pulse hose to the fuel pump is not loose , it pumps fuel, the diaphragm looks good and was installed properly in the top , i can't find the problem. I am thinking about buying a new carb , and have heard i can get a 40 mm carb and turn this 97 into an HO , does anyone know about this and what year carb will interchange ? Anyone know why i am having these problems?
 

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I bought a nice looking purple scrambler 500 for 400, it acted like the carb was clogged, but it turned out there was all sorts of problems, mostly from shitty mechanic work. The flywheel was busted, the stator was bad, it was out of time by one tooth and the chain was stretched. The cam looked brand new almost, also the decompression spring was installed wrong. Anyway i have fixed most everything and got it to run but now again i am back to the carb not working. I have rebuilt the carb using an ebay rebuild kit, and already had to re install the old float needle since the new one just would not seal. Now it's really hard to start, when it does start it will idle fine but will not take gas , so i removed the air box and filter again and adjusted the choke completely in so that can't be the problem, but what it is doing is the slide will not raise up, i can reach in and push the slide up with my fingers and it takes gas really good, but it just wont work by itself and also it is making huge amounts of carbon, obviously it is running rich , i am not sure if its because the slide wont open or the jets in my rebuild kit are all wrong, but first things first , what could be making the vacuum slide not operate? I can't find any leaks , my pulse hose to the fuel pump is not loose , it pumps fuel, the diaphragm looks good and was installed properly in the top , i can't find the problem. I am thinking about buying a new carb , and have heard i can get a 40 mm carb and turn this 97 into an HO , does anyone know about this and what year carb will interchange ? Anyone know why i am having these problems?
Isn’t the slide vacuum operated on these carbs ? I may be wrong . It’s been a long time since I worked on one . If so i don’t think they go up and down Instantly when you stab the throttle .
 

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Isn’t the slide vacuum operated on these carbs ? I may be wrong . It’s been a long time since I worked on one . If so i don’t think they go up and down Instantly when you stab the throttle .
yes it is vacuum operated, but it will not go up, i can push it up, it moves freely like it should, i can see it trying to go up , it just wont by itself, when i do push it up it takes gas just like it should and remains up, then i can let off the gas and it closes again, someitmes it seems to want to work just a little better, i just can't find the problem or leak.
 

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Isn’t the slide vacuum operated on these carbs ? I may be wrong . It’s been a long time since I worked on one . If so i don’t think they go up and down Instantly when you stab the throttle .
like i was saying it is getting plenty of gas also, the plug keeps getting coated really thick with carbon
 

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Isn’t the slide vacuum operated on these carbs ? I may be wrong . It’s been a long time since I worked on one . If so i don’t think they go up and down Instantly when you stab the throttle .
It takes rpm and vacuum to operate it. May be a stupid question but are you 100% sure you have the slide in the rite way? It should have a small lip on the diaphragm that will set in a notch in carb and then line up cap the same. Sounds crazy but Iv Seen people put them in backwards . Id start by just making sure you have everything tight and right. If the jetting it’s way off it’s Gona smother itself to death and not open the slide . Did you shim the needle Or go way up in jet sizes ?
 

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One real problem here though . Unless I’m reading wrong ,you could possibly be chasing two problems at the same time or the wrong problem .Unless at one point it ran good after the you done a timing chain. This is what sucks about trying to fix a bunch of things at once . Iv gotten into the exact same scenario on a brute force I built. I bought with blowed motor. it ran like crap And I too chased a carb problem and it was the timing all along .
 

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1995 magnum 425 4x4 2019 sportsman 570 2020 sportsman 850
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Man this sounds exactly like a 500 I just bought. You can get carbs cheap on amazon or ebay and the one I jsut got for my magnum works great!
 

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One real problem here though . Unless I’m reading wrong ,you could possibly be chasing two problems at the same time or the wrong problem .Unless at one point it ran good after the you done a timing chain. This is what sucks about trying to fix a bunch of things at once . Iv gotten into the exact same scenario on a brute force I built. I bought with blowed motor. it ran like crap And I too chased a carb problem and it was the timing all along .
When i got it i was able to get it to run somehow, it ran really terrible even being out of time and the other problems, the carb had been messed with before i ever got it, the air screw was missing its spring, it was clogged really bad with ethanol or dirt residue, i did rebuild it but i don't even trust the rebuild kit parts since the float needle never did seal, maybe the jets are way to big or something like that, I'm about to buy an ebay carb and try it but if i get a new carb i want to go with the upgrade , a 40 mm from a later year when they were called HO engines, i just have to figure out which one it is i need to get.
Man this sounds exactly like a 500 I just bought. You can get carbs cheap on amazon or ebay and the one I jsut got for my magnum works great!
What year and size carb did you get? i might get one but if i do i understand i can get one from the years they were called HO and gain a little power , its a 34 mm to 40 mm size difference , anyway which brand did you get? I know i look at the adds and they all look like the exact same carbs with the exact same add just from different sellers.
 

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When i got it i was able to get it to run somehow, it ran really terrible even being out of time and the other problems, the carb had been messed with before i ever got it, the air screw was missing its spring, it was clogged really bad with ethanol or dirt residue, i did rebuild it but i don't even trust the rebuild kit parts since the float needle never did seal, maybe the jets are way to big or something like that, I'm about to buy an ebay carb and try it but if i get a new carb i want to go with the upgrade , a 40 mm from a later year when they were called HO engines, i just have to figure out which one it is i need to get.

What year and size carb did you get? i might get one but if i do i understand i can get one from the years they were called HO and gain a little power , its a 34 mm to 40 mm size difference , anyway which brand did you get? I know i look at the adds and they all look like the exact same carbs with the exact same add just from different sellers.
Good to hear! at least you’re making progress.I wish I could be of more assistance on the carbs that will or won’t work. If was any kinda sport quad I could tell you but outside of that I have no clue . If you did change the jets I think just for curiosity id clean the stock ones and put them back in. If it’s running but Still running bad that is.
 

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1995 magnum 425 4x4 2019 sportsman 570 2020 sportsman 850
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It is a Fyange but I cannot find it on amazon anymore. It was $46.99 and came with air filter (that didnt fit) fuel filter, some hose and clamps. I havent put one on my scrambler yet, this was for the magnum. I have the mikuni that came with the scrambler im gonna clean up before I order another. I was told the previous owner tried to make it a HO and changed the cam and it didnt run right after. Im thinking he got the timing off a notch but havent torn into it yet.
 

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Discussion Starter #11
Good to hear! at least you’re making progress.I wish I could be of more assistance on the carbs that will or won’t work. If was any kinda sport quad I could tell you but outside of that I have no clue . If you did change the jets I think just for curiosity id clean the stock ones and put them back in. If it’s running but Still running bad that is.
I will at least try adjusting the needle jet , the one that goes up with the slide, maybe it is adjusted way to rich or something. And probably take it off again and re install all the old parts if that doesn't work, its just a big hassle and a head ache , but yeah i started out thinking it was a carb problem, the fuel lines were no where near right , i think there were 3/8 fuel line on it and the pet cock is turned around backwards, lol. it was all jacked up, lol. That is what i started with and now i am back to the carb after fixing everyghting else, i saw it was out of time by checking the cam , then i couldn't get it set quite right so i got a timing chain, then i saw the flywheel was busted up, then i saw the stator was mangled to bad, and like i said now i am back to the carb again,
 

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It is a Fyange but I cannot find it on amazon anymore. It was $46.99 and came with air filter (that didnt fit) fuel filter, some hose and clamps. I havent put one on my scrambler yet, this was for the magnum. I have the mikuni that came with the scrambler im gonna clean up before I order another. I was told the previous owner tried to make it a HO and changed the cam and it didnt run right after. Im thinking he got the timing off a notch but havent torn into it yet.
that was one of my problems, the cam looks new but it was retarded one tooth on the cam gear and stretched chain, when i put it back together i had to do it twice, i got it one tooth off also the first time, when the tensioner tightens it it seems to pull back some, but thats why we check our work, lol. The cam decompression spring was also wrong , my clymers manual has terrible images, i just had to keep guessing at it until i got it, i could not see the tiny spring in the picture.
 

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It is a Fyange but I cannot find it on amazon anymore. It was $46.99 and came with air filter (that didnt fit) fuel filter, some hose and clamps. I havent put one on my scrambler yet, this was for the magnum. I have the mikuni that came with the scrambler im gonna clean up before I order another. I was told the previous owner tried to make it a HO and changed the cam and it didnt run right after. Im thinking he got the timing off a notch but havent torn into it yet.
you mentioned they tried to make it an HO , i have read that the available cam is the same as the HO cam, just a little more duration, and the carb upgrade from 34 mm to 40 mm makes it an HO , do you know what year carb i would have to get that would fit? the ebay carbs all look different than the one on it, the idle control is different, the throttle cable goes to the opposite side, so i am a little hesitant to just buy one.
 

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I will at least try adjusting the needle jet , the one that goes up with the slide, maybe it is adjusted way to rich or something. And probably take it off again and re install all the old parts if that doesn't work, its just a big hassle and a head ache , but yeah i started out thinking it was a carb problem, the fuel lines were no where near right , i think there were 3/8 fuel line on it and the pet cock is turned around backwards, lol. it was all jacked up, lol. That is what i started with and now i am back to the carb after fixing everyghting else, i saw it was out of time by checking the cam , then i couldn't get it set quite right so i got a timing chain, then i saw the flywheel was busted up, then i saw the stator was mangled to bad, and like i said now i am back to the carb again,
This sounds just like all my projects! Lol . Well if it’s idling and starting now then the pilot jet is probably fine. If the needle is adjustable I’d start at top clip or second from top then work my way down . The higher the needle sets in the slide the more fuel in mid throttle . Sounds like your on top of it now tho. If it’s stock needle it’s probably non adjustable . You can shim them with small washers . But if you planning on swapping carbs I wouldn’t mess with it a whole lot. That’s what I always loved about the 450 sport quads . No taking stuff off to do carb work. Loosen clamps turn carb sideways to either work on needle side or main jet side . Wished they were all that simple !
 

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Here’s my current project . It was a total basket case when I got it . Iv about got it ready to sale tho . So I feel your pain buying stuff someone else jacked up Lol this wound up being a huge project from engine build to re painting the plastics and new decals . And all new bearings and seals. Luckily I got it for almost nothing
143075
 

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Here’s my current project . It was a total basket case when I got it . Iv about got it ready to sale tho . So I feel your pain buying stuff someone else jacked up Lol this wound up being a huge project from engine build to re painting the plastics and new decals . And all new bearings and seals. Luckily I got it for almost nothing
View attachment 143075
That looks nice , you did good work, i have an 2004 or 2005 arctic cat 650 V2 , i love it besides a carb issue with it that i did myself , i bought a jet kit from Sigma 6 , i asked them for a very slightly heavier jet set, just because i am at 400 ft above sea level around here and i know ATV's are generally jetted really lean from the factory to comply with Emissions, they sent me what must be a full built race engine jet kit that is way to rich , it runs great but in cold weather the carboned up plugs will not fire unless i pull them and clean them, also i never did sync the carb , but it is basically a kawasaki with arctic cat suspension , i have wheels on it from a newer side by side take offs. I would post pics but i never have been able to get them to work.
 

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This sounds just like all my projects! Lol . Well if it’s idling and starting now then the pilot jet is probably fine. If the needle is adjustable I’d start at top clip or second from top then work my way down . The higher the needle sets in the slide the more fuel in mid throttle . Sounds like your on top of it now tho. If it’s stock needle it’s probably non adjustable . You can shim them with small washers . But if you planning on swapping carbs I wouldn’t mess with it a whole lot. That’s what I always loved about the 450 sport quads . No taking stuff off to do carb work. Loosen clamps turn carb sideways to either work on needle side or main jet side . Wished they were all that simple !
yeah there is an extra spacer below the clip, i do not know if it belongs or was added by someone when the carb was filthy and clogged. also i am noticing there are slight differences in the needle jets from stock to the rebuild kit, i used the factory needle but will first try the rebuild kit needle without the spacer , even in my clymers manual it shows on some models there is a spacer but i think there's two spacers, one really weird shaped , oh well i will just keep trying every possibility and see if it helps.
 

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I found a drawing just now on manualslib.com that shows a spacer going above the e clip, as i look at the spacer i can see it is shaped to mate against the spring, i put the carb back together the way i took it apart but i am thinking i found the problem, its about an 1/8 inch spacer and if its wrong it has been holding my jet needle way to high making it run way to rich , i hope this is the problem, i am so sick of this one ATV holding me up on so many other things, lol.
 

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You are running it with the airbox and stock "snorkel" installed, right?

If not, it will NOT open the throttle. Even with the snorkel missing, those CV carbs won't open properly.

Sent from my SM-G930R4 using Tapatalk
 

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1995 magnum 425 4x4 2019 sportsman 570 2020 sportsman 850
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you mentioned they tried to make it an HO , i have read that the available cam is the same as the HO cam, just a little more duration, and the carb upgrade from 34 mm to 40 mm makes it an HO , do you know what year carb i would have to get that would fit? the ebay carbs all look different than the one on it, the idle control is different, the throttle cable goes to the opposite side, so i am a little hesitant to just buy one.
Im really not sure. I havent messed with this bike at all yet but I hpe to tear into it soon
 
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