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Discussion Starter #1
I let my friend ride my lt250r with about 20 hours on it.
It got low on gas and leaned out and started revving uncontrollably. He didn't know how to kill it -_-
It revved for a lil under a minute before I could run over and shut it off. Now it seems like it just doesn't have that same kick it had before. It still runs perfectly fine, it just seems slower. Is it all in my head? Or is there a chance that high revving has done some damage?

Thanks
 

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Well when they run out of fuel like that they run lean and hot, which means you could of burnt away some piston/rings prematurely. So yes it is possible, they only way to really tell is to compare the compression to they way it was before this and the way it is now.
 

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PLAYTIME'S OVER BITCHES!!
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it could've done some damage due to lack of lubrication. scored cylinder wall, prematurely wore the rings, or even seized a ring.. if it ran like that for that long, i'd be pulling the topend down to have a look, especially if it feels low on power now.

welcome to the site btw.
 

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Like strokeittwice said, I'd be looking into the top end just to be sure. Sometimes things can get in our head, it seems I'm bad for that. But wither way, I'd check to piston/rings/cylinder just to be safe.

:welcome: to the site.
 

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PLAYTIME'S OVER BITCHES!!
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depending on the length of time it ran like that. high speed revs and no lube is a recipe for disaster. the chance of damage is high. better off to check it now, instead of it coming apart 10 miles away from your hauler on the next trip out.
 

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compression test ! .02
 

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Discussion Starter #8
Im not sure if I can pull the motor apart, I might have to find a mech for that, I can probably do a compression test but I imagine it would pass because it still hauls ass but it just seems a tad bit less than before (my raptor still gets trashed hauling ass lol).
What compression should a 87 lt250r be?
 

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Discussion Starter #9
I guess a better question would be, in that scenario would the damage done be minor enough to be barely noticeable or if damage was done if any I would know and it would be significant?
 

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minimally if your gonna pull the top end i would hone the cylinder and use new rings, after you get it determined its with spec of course... Also how hot and humid is it where your at? it would also be caused by running a bit to fat on top end now that we are in summer and the temps are higher, compression test and plug chop..... but you kinda wanna know if this thing is gonna come apart before rippin wot for the chop....can you get a pick of the intake and exhaust side of the piston??? rebuilding these is easy so dont worry bout that!!
 

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buy a book for it to help you, but almost anyone is capable of pulling off the top end and replacing it on a single 2 stroke, it really is not that difficult if you have basic tools and are somewhat mechanically inclined. a top end gasket set runs around $40 maybe even cheaper (call rjatv) and it will give you the peace of mind you are looking for it is the only way to be 100% sure that nothing is wrong and is better than waiting for it to blow up and cause more damage.
 

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Discussion Starter #12
It is very hot and humid here but the difference was noticed on the same day, but maybe I was looking for it to be different and I can be a little ridiculous and let stuff get in my head that doesn't really exist. I rode it maybe 10 hours or so after that happened, so I probably am just crazy.
I'll see if I can get the piston pics from the intake and exhaust tomorrow or possibly this evening.
Thanks for being helpful guys and hopefully nothing has been damaged.
 

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try popping off the exhaust and having a look in the cylinder and see if you notice any visable wear on the piston... as for doing the top end, its really simple. Theres even videos on youtube of people doing top end rebuilds. heres a video of a top end rebuild on a dirtbike, just so you get an idea of what all is involved... for your lt its actually easier to do then this dirtbike there showing : http://www.youtube.com/watch?v=-FFIWtqU5Zc
 

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Discussion Starter #14
You think if there is no visible wear on the piston then I am probably good, and proves I am crazy?
As far as top end goes, is that just replacing the gaskets?
 

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Damage is somewhere between quite possible and likely. Getting the pipe off to have a look inside the easy way was great advice. Go ahead and pull it, you can do it. If you find yourself in a pinch, there's nothing this group can't walk you through.

Another idea...I'm not an LT guy so I can't remember if the 87 motor is powervalved or if that powervalve is prone to failure. But in the Tecate world, the most common way to diagnose a broken powervalve is using your exact words..."It runs good but just not quite as good as it used to". Of course, this is also the symptom of lost compression, which the others have already described the possibilities of.
 
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