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Discussion Starter #1
Well, I'm burried in my machine and it has a lot of sentimental value to me so I want it to be right. It's a 96 sportsman 4x4 400L.
The problem: My rear chain is skipping. I've adjusted it 100 different ways. When it first broke I replaced all 6 sprockets and all three chains. I pulled it out of my garage and as soon as I gave it full throttle, POW! The rear drive sprocket broke 4 teeth. I decided the angle caused by the lift (2") was too harsh so
I took it off. Just to be safe and keep the chain off the swing arm I had two new larger sprockets made (rear drive and rear attached to axle) but kept them equivalent to stock ratio. I thought I had the problem fixed but as soon as I stood it up coming out of a mud hole it did the same thing. 2 teeth chipped on the drive and one on the rear. I can't exactly watch it while I ride and it doesn't do it under normal riding conditions. I am very hard on my machine and put it through hell but I am extremely meticulous in building and maintaining. Just hoping one of y'all have run into this because I am so stumped.
 

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You need to gear it down to run such a large tire and in the mud too. They were never geared or built for what you are doing to it. Friend has a scrambler with a 583 Rotax in it that runs 30" tires and had to go real deep on the gearing. Next time I see him, I can count the teeth and let you know where he ended up.
 

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Discussion Starter #3
I realize that it was not designed to do what I am doing and I do foresee my fair share of problems in the future. I have had plenty of people tell me to just sell it and get one more geared to do what I am doing or just stick to the trails. But there really isn't a wheeler "designed" to take that much punishment and I don't have a problem putting the money into it to prepare it the best I can. Rick at Ritter Cycle told me to gear it any lower would be pointless since low gear is already so low and I am pushing a little over 60hp with my mods. I know it is a stubborn thing to do to force it to be something it's not but since I'm this deep it's hard for me to put the shovel down now and give up.
 

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torque is no longer your friend. and last I checked, to much torque and chain drive don't go together very well. are you problems only happening on the final drive chain? is it possible to get a custom made double chain/sprocket set up? That way you're doubling up on the strength not changing the gearing and thus the torque.

I'm fairly new to ATV's and my machine is shaft drive so I'm a bit out of the loop on what can and can't be done with chain drives, but if it were me, that's the direction I would be looking into.
 

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Discussion Starter #5
It is only the rear chain and sprockets. The middle and front don't seem to have any trouble at all. I believe it is because of the amount of slack/tension generated from bouncing on uneven terrain majority of time on two wheels. A double chain setup seems interesting and wound give more strength but I'm afraid it would only compound the problem. The strength is there I just can't keep in on the sprockets. I was kinda leaning toward a tensioner or guide of some description but don't have experience with either. It's difficult to try advanced technology on this antique. With all the chain driven race bikes out there I know someone else has had this problem before...
 

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Is it possible to get a custom made double chain/sprocket set up? That way you're doubling up on the strength not changing the gearing and thus the torque.
I think Hammer may be onto something here.... keep digging and go "double down" so to speak and mount double sprockets and a second chain if space allows!!!
 

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My friends scrambler is putting out 115hp, which is close to double what your 400 does I bet. He has no problems after gearing way down. Also has an extended swingarm.
 

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Discussion Starter #8
My friends scrambler is putting out 115hp, which is close to double what your 400 does I bet. He has no problems after gearing way down. Also has an extended swingarm.
Wow, that's impressive! I feel like a have plenty of horsepower. In low it revs up awefully high even at low speeds. I am having a hard time seeing where lower gearing is going to help...
A double chain setup is out of the question. I only have 9/10" of space to work with
 

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I'd see what sizes you can find in a double chain, you might be surprised. Also it could be possible to clearance some things to make more room. But if that's not what you're interested in doing, Chain tensioners/guides are actually pretty simple devices. A sprocket on an arm that is spring loaded and moves with the chain. shouldn't be to hard to make yourself, or have made for you depending on your fabrication skills and the tools you have. I would think you could do this with basic hand tools and a drill/drill press.
 

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I would also recommend checking your swing arm pivot bushing and carrier bearings for excessive slack. If something is loose and shifting around your chain could try to jump off the sprocket causing the broken teeth.
 

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Discussion Starter #12
I just put both new bushing in the rear. The right one took about 10 minutes. The left one took a little over an hour. The smallest double chain/sprocket setup I've found is 1 1/4". I'll be in the machine shop this weekend trying to fab up a tensioner of some description. This has turned out to be one of my worst hang ups yet. Thanks for the thoughts and encouragement guys!
 

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I know nothing about the 400L, but looking at the diagrams, I see several tensioners on this drive train, could be an issue with one of the tensioners. Is there any play in you swing arm, maybe old bushings?
 

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Discussion Starter #14
I know nothing about the 400L, but looking at the diagrams, I see several tensioners on this drive train, could be an issue with one of the tensioners. Is there any play in you swing arm, maybe old bushings?
Several tensioners??? I have no tensioners at all!
 

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I think he's talking about the eccentrics for your front and middle drive chains.
 

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you could possibly put a spring loaded tensioner on it to keep the slack out of the chain under higher loads and suespension movement and torque my old trailblazer had a chain guide just before the rear sproket …does yours have something similer ?
 

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Discussion Starter #17
It does have eccentrics of course for chain adjustment but they do nothing for riding tension. I have 4 different spring style tensioners I'll be in the machine shop in the morning with tryin to figure this out.
 

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Discussion Starter #18
Problem solved! I attached a tensioner to the bottom side of the chain and it did nothing. A little confused, I decided to attach a gopro to the rear axle to see just what it was doing. Under full acceleration it was gathering slack in the top side of the chain and skipping across the top of the teeth on the drive sprocket. I swapped the tensioner to the top just in front of where it feeds into the drive sprocket and I can't get it to misbehave. Time to abuse it some more and see what I can tear up next! Thanks for the help gang.
 

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i would love to know how you cleared 29.5's ....i have a 97 polaris magnum 425L and it is chain driven ...i want to upgrade the sprockets, chains, and i have a 2" lift on it but can only clear 27's and i know 29.5" OL2's run a lil bigger than 29.5 so can you spill some beans lol or take pics? thanks, i read ur signature btw and would like to know more about the clutch kit, custom sprockets, and you lift ...thanks man!
 

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Discussion Starter #20
I'm glad to help with whatever I can! I strongly recommend bumping up the power because the 29.5 OL2s are a power killer. The clutch kit is from epi. If you tell them what you are running they will fire you out the right kit. I was told not to gear it down any more because low gear is already so low. The reason for the custom sprockets is strictly for clearence issues (around the swingarm). I kept the ratio the same as stock. This is how I fit the tires.
 
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