Help! Bottom end?

Joined
Jun 16, 2004
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#1
Hi guys

Have a 98RMX250S and it shat itself on monday! Rode it for about 3 mins and it locked up whilst hooning down a strate. First thought was that i had siezed the top end as when i slowly pushed the kick start down it sounded a little ' grindy '. but once it had cooled down when i pushed kick start down there was still good copmpression and the ' grindy ' noise seemed to be coming from the bottom end. not a very loud noise but happens once on each cycle
So after removing spark plug and exhasut im pretty certain the top end is ok and have also drained gearbox oil and that is all clean too.
Removed fly wheel cover to check for up and down play and there is only a very tiny bit of movement. SHould this have heaps of movement if the bottom end is buggered??
I will eventtually strip it down to find the problem but thoight id ask first for some ideas first
Cheers!
 

IndyMX

Crash Test Dummy
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Jul 18, 2006
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#2
It should have NO movement up and down, any movement like that is a bad thing.

Might as well freshen the topend while you have it apart..
 
Joined
Sep 8, 2006
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#3
IndyYZ85 is right. Any movement in the flywheel is a BAD thing. Sounds to me like you're getting ready to hear those two dirty little words, bearings and seals. You have already described three of the main symptoms of the bearings going out; locking up, weird sound, and movement in the flywheel. This is why your oil is clean(no metal shavings) and why your top end is probably ok as well. However, if it is the bearings you should do a topend and have a whole new engine. Sorry to be the bearer of bad news. Hope this helps.

Michael