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91 yz 250 metal shavings..........

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Ok so i was riding and i think i was in second gear and i wrapped on the throttle and i was getting fom like mid-high rpms and the bike kind of bogged and died. At first I thought it was the top but then i tried to kick it and it was locked and I have been having problems hitting false neutral and i changed the tranny oil every two rides because it seemed to help for a bit and then it would start slipping again. I have no clue what it might be because i need to take off one bolt to get the cylinder head off but i seemed to misplace my 14mm wrench and i dont have anything that would suffice until tomorrow wen i get paid and i can go blow a whole bunch of cash on tools and parts :) but im just wondering what you guys think it might be. Im just a newbie with this bike wrenching stuff so take it easy on me lol. I found metal shavings as soon as i took off the exhast pipe and when i changed the tranny oil several times before i didnt see any either which is why it didnt bother me too bad. but it still bothered me......... now im facing the consequences........ so let me know what you guys think. Thanks guys!

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Edited by yz250ripper

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First, reading that gave me a head ache.

Second, your bike is a two stroke. Your tranny oil has nothing to do with the crank shaft, piston or cylinder therefore you would not get metal from the crank into the transmission. It's not possible unless the cases become compromised.

Third, your bike shattered the piston skirt. You will more than likely be completely rebuilding the top and bottom end including getting the cylinder recoat. Good luck

Last but not least, this issue has absolutely nothing to do with your bike hitting false neutral.

Edited by Woodsweapon350
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Sorry about the long never ending sentences. I was just thinking that the tranny problems might have been a factor. (Like I said, i'm a newbie) But thank you for your input. Im gonna order the parts tomorrow..... Anything I should know about going about the rebuild? This might be a dumb question but would it almost be a good idea to get a new motor? I mean I have the manual but i'm just wondering because the best knowledge is from experience!

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The rebuild, if it's your first time, isn't what I'd call "easy". Although it's not hard, there is quite a few pieces and if you're not completely competent things could be mixed up or left out. I've never seperate an older motor like that but I'm sure it's similar in ways to the new. Every yz I've ever rebuild wasn't fun to separate the cases and required a case splitting tool.

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Don't order a piston until know exactly what size it is. Don't get the cylinder re plated without sending the piston with it so it's matched. Ordering parts before you know what you actually need is like buying smaller sized pants before you loose weight. First things first, tear it down and sort all your ducks out on the table. Figure out what needs replacing and make a list. Don't be in a hurry. I've done many top ends and one bottom end. Good luck. By the way if you do do an entire top and bottom engine rebuild be sure to replace EVERY bearing and seal in the engine. Be sure to JET IT CORRECTLY ALSO AFTERWARDS.

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