worn output shaft on the kdx

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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kawacowboy
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worn output shaft on the kdx

Post by kawacowboy »

Hey, is anyone else out there having output shaft failure? Been riding through the ditches and woods on kdxs daily, year round for about 30 years. My trusty '03 stripped less than a month ago providing a good hike in the heat through the brambles to get the trailer. Had to get out the '06 I'd just had the top end replated on with new Weisco piston. New pipe and silencer, brake pads and wheel bearing kits front and rear. 35/142 seems fine but pilot is lean. I'm careful not to hold 3/4 to full throttle for long. Amsoil Saber 50/1. This '06 has the shaft splines noticeably worn to allow slack. I expect to hike again soon. Had to replace shaft in a '97 a few years ago. Still have it. Leaked oil after reassembly. Replaced O ring and didn't fix. Took to local atv mechanic. Still leaked. I've split the case on about 5 different bikes and there always seems to be something. Need to have time to get in the right mood to start in on it.
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Tedh98
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worn output shaft on the kdx

Post by Tedh98 »

kawacowboy wrote:Hey, is anyone else out there having output shaft failure?
No problems here.
kawacowboy
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worn output shaft on the kdx

Post by kawacowboy »

Thanks for reply. suspected it was not common as I've searched for topic through list. Happy to find this site a good while back. Finally decided to post a problem I've had and see what others think. I have front cover off front sprocket and plastic worn through on chain slipper. Large rear sprockets not friendly to slipper. I didn't think this would make much difference. ?? I read reviews about the DID520VM chain being a little wider. Even wondered if that extra width might have allowed to rub on case causing that leak on the '97 as the sprocket stripped splines on it's shaft. Even read a post about re-using an old chain when installing new sprockets. Mine has missing rollers by then. Of course I run till the front slips on occasion. I do realize a spell or two of that can bring havoc to splines. I try to ease it back to the shop when and if it gets to that point. This 2nd and soon to be 3rd shaft failure will bring more attention to front sprocket wear in the future no doubt. For now I'll look back to that case splitting thread. Hope to hear more. I realize output shafts cannot last forever. Just haven't heard of many having to be replaced. In the past I've not checked for a good tight fit when installing front sprocket. With new shaft I will. And if there is slack I'll probably try another sprocket from another manufacturer. Once the backlash starts I presume it wears fast with water sand rust working for the kill.
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doakley
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Re: worn output shaft on the kdx

Post by doakley »

Pardon my directness but it sounds like something you are doing possibly. Do you run the chain a bit tight perhaps? Admit I am clueless but intrested in the cause.
kawacowboy
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Re: worn output shaft on the kdx

Post by kawacowboy »

Not too direct at all as I appreciate your suggestion. I have over tightened on occasion. Seems easily done with a worn chain as I've had to back off a notch after a check ride more than once. When I was running a 12T on front it wore faster. Given that you've got me thinking I need to replace chain and sprockets sooner. I'll bet most of the stress of tight chain comes from the life during the last two adjustments. And I don't get much service out of that short period anyway. Was reading a thread earlier about a fellow getting O ring chain and steel sprocket set for $70. Cheaper than output shaft alone not counting the case split involved. He also said he had 5000 miles with only 1 adjustment. That won't happen here. I've also run too loose of course before tightening. I believe it was my CRF manual that mentioned possible damage to the case by a loose chain. I did take that to heart as I suspected that chain wobble prior to the '97 shaft failure might have caused the oil leak I had after new shaft installation. BTW I use Mystik 90w on chain about once a month. Sliders worn. Don't remember the roller. Are these more important than I was thinking?
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Tedh98
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Re: worn output shaft on the kdx

Post by Tedh98 »

I'm not sure I have followed everything you have said, but from the bits and pieces, I would guess that you are going too long between servicing and replacement intervals.

This is how I adjust the chain for my bike - proper chain slack. Initially it does take some extra time and effort, but after that you'll never have to guess if you chain it too tight.
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Tyl3r
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Re: worn output shaft on the kdx

Post by Tyl3r »

Ted - when you take the shock off and line up the sprockets, how tight are you making the chain? tight? I would think you would want close to zero slack at the point of max travel
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Tedh98
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Re: worn output shaft on the kdx

Post by Tedh98 »

Tyl3r wrote:Ted - when you take the shock off and line up the sprockets, how tight are you making the chain? tight? I would think you would want close to zero slack at the point of max travel
There was a formula for it - for a X span of chain with Y pounds applied to the middle of the chain, you wanted Y deflection. I received that information in one of the TT monthly newsletters years ago. You can probably find it without too much problem.

I just went more on what seemed like a reasonable amount of tension on the chain when everything was aligned. I tried to go a little looser to account for muddy conditions when the chain would be a little tighter with mud packed between the chain and sprockets.

I figured my un-scientific approach was still better than the "3-finger" method.
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worn output shaft on the kdx

Post by canamfan »

I take a tie down strap and hook it on the rear sprocket loop it over the seat and hook it on the other side, then pull it down till the countershaft, swingarm pivot and rear axle are in line then adjust the chain with about an inch of travel. When you release the strap you might be surprised how loose your chain is, but it needs to be as you can see how much it tightens under compression plus mud in the rollers will take some slack out too.
kawacowboy
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Re: worn output shaft on the kdx

Post by kawacowboy »

Sounds like I've been too tight alright. After posting my 1 1/2" slack setting I thought I remembered 2.2" from the manual. Sure enough 2.2 - 2.8". almost 2X my previous setting. My new chain will get over 2". And I'll be alert for binding from mud and or sprocket wear. Thanks to all who replied. And helped me think in the right direction. I'm guessing my chain and sprockets will last longer. And of no lesser importance my output shafts.
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