KX Riders
Maintenance & Technical => KX250 / KX125 => Topic started by: blackkx on January 14, 2007, 09:56:57 AM
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Just wondering how tight the rear axle nut should be . I think i tightned it to much , because after a 4 hour ride today it started making a loud popping sound when i spun the rear tire backwards on the stand . I thought it was my rear brake but i loosened the axle nut a 1/4 turn and the popping went away . Did i over tighten it ? please help ...... :? :? :?
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i geuss its fine the brear brake functions properly and the tire spins nice and smoothly now . Nothing else on the rear of the bike seems to be positoned wierd or overtightened in any way , should i leave this problem at rest and just ride the bike or should i be more concerned?
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the rear axle nut just has to be snug, not too tight make sure you have a cotter pin or safty wire on the bolt, so you dont lose your axle nut!!!!
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cool . thanks man and yes i do have a cotter pin trhoug the nut .
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You should torque the rear axle, 98N-m (10 kg-m, 72 ft.lb.)
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As Danger says, 72 ft-lbs is pretty tight. You might have a rear bearing going. The tighness may stress it enough to sideload the bearing. I am too lazy to torque so I crank mine super tight with a 20" flexbar. No issues. Cam.
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98N-m (10 kg-m, 72 ft.lb.) That's the factory service manual.
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Just wondering how tight the rear axle nut should be . I think i tightned it to much , because after a 4 hour ride today it started making a loud popping sound when i spun the rear tire backwards on the stand . I thought it was my rear brake but i loosened the axle nut a 1/4 turn and the popping went away . Did i over tighten it ? please help ...... :? :? :?
The popping sound when you turn the wheel backwards sounds more like chain and sprockets. Check to see if your teeth are worn and bent over. I would think if it was a bearing it should make the same noise turning it forward or backwards. Let us know.
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98N-m (10 kg-m, 72 ft.lb.) That's the factory service manual.
I am a strong beliver in owning a service book for every vehicle i own. they are cheep.
as for the poping sound check the runout on your rear sprocket
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You guys are right. The popping would not be the bearings. Rear sprocket is the best call. Cam.
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That's what it was on mine, the chain was over due to be replaced. New sprockets front and rear, and a new chain, and all is well.
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i am gonna replace the chain and sprockets , i think you guys are right the chain block wore through and the chain is rubbing the aluminum on the guide . Result - the chain has scratch marks in the side of the links and i dont trust it anymore . the teeth on the rear sprocket are fine but the front teath are starting to bend , i already ordered the chain block yesterday. via dennis kirk . I am thinking of changeing the sprocket sizes to favor a little more top speed , sizes now f13t r52 , what do you guys suggest ? will minor size change be that noticeble ? I ride mostly motox and trails , the trails are where the 450s leave me trying to play catch up . :x :x :x
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Bigger sprocket on the back and smaller sprocket on the front will give you more low end. Smaller sprocket on the back and bigger on the front will give you more top end speed. Yes small changes in sprockets does make a difference. I'm making my K5 more woods friendly. Adding a flywheel weight and going from a 47 tooth rear to a 50 maybe 52 tooth. If you go to big or to small on the front sprocket you run the risk of the chain eating into the motor case.
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On my '04, I run a 13/49 for MX tracks, 14/49 for HS and GP's, and a 15/49 for desert. The 15/49 tops out at 85, plenty fast for me.
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keep in mind changiong one tooth on the cs sprocket is almost equal to 3 teeth on the rear. i like to try to keep smaller rear sprockets to miminize chances of hitting stuff. there is a gearing calculator somewhere on this site.
~stevre
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I wouldnt go too small on the cs sprocket though, it increases wear. I find stock gearing pretty acceptable, for my bike any way. Gearing is a cheap way to change the power band though.
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my bike has a case saver on cs sproket that has 13t printed on the side of it , where can i find one for a 14t sprocket ? i have held off on ordering the chain and sprokets due to this . but thats not the only problem , the rear wheel bearings are junk , i left it the way it was and rode it friday and when i was done and loaded in the truck i grabbed my back wheel and there was definatly some play there . I think maybe the bearings had so much play that when it was to tight it was side loading the bearings , hence the popping noise . the noise is definatly coming from the brake side of the rear wheel . new bearings and seals for the rear wheel are on the way , will se what happens then . btw it has a 92 kx250 rear wheel on it and it takes 1 bearing per side and the 98 wheel has 2 bearings on one side and 1 on the other , the spacers, axle and all the hardware line up and seem to fit properly . could that be a problem ?
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well i replaced the wheel bearings and went with a 13/49 sprocket sizes , I can notice a difference on top end , but it still pulls hard on the track so i think i found my happy medium . the bike is back in order . thanks for all your input !!!