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My cr250 locked up

By guitarromantic,
in Honda 2 Stroke

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guitarromantic

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So I went riding with a fellow TTer last week on my 1998 cr250. Everything was great, I had rebuilt my first top end a couple months ago by myself after reading my manual and watching tons of videos.

I went riding a bunch of times since and everything sounded great. However, my throttle cable must have been poorly routed because when I reached the top of a trail it got stuck wide open. Unfortunately, my killswitch had slid too far away from my thumb to reach and I panicked. I decided to bail instead of hold the clutch in :smart: So after eating sheet and making sure there was no sheet in my pants I quickly hobbled over and killed the engine (by this point, maybe 15 seconds after crashing the bike was down the trail and NOT stuck wide open).

My riding buddy actually hopped on my bike and bump started it down the trail and rode it up and around to the top of the hill which was a closer hobble for me than the bottom of the trail. So the bike actually ran fine after the crash... then we sat around. Figuring out where we were and fixing the cable routing, we probably sat there for a half hour. My leg hurt and my bars were bent but I needed to get back to camp so I go to fire her up. Thats when the sheet hit the fan.

When I kicked it over (took a couple times) it fired up and immediately I knew something was wrong. A little boggy sound followed by a rattle (like the tab of a can of soda inside the can rattling around) and immediately the motor died and crank locked up. This all happened in seconds.

So yesterday I took the top end off and this is what I found..... (looking for pics upload button)

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guitarromantic

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Okay so when I opened it up those metal pieces were sitting right on top of the crank. The piston looks fine to me, so I am confused. Can someone tell me please where those came from? I have the engine off the bike now, what do you all think is the best course of action? Cylinder replate, top end, new crank (not wiseco or hotrod) and..... ??? Of course theres probably more than meets the eye and the bottom end needs gone through and flushed out as Im sure theres tons of metal and god knows what down there. Anyone with any worthy/encouraging advice to help me through this mess is much appreciated! I just wanna get back to riding...

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Kirkes

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It looks like it was a washer.

Plating looks warn. Measure the cylinder to bore clearance my be time of a new plate job.

Side play on big end of rod looks out of spec.

How do the crank bearing s feel? Any movement in them at all.

Are the tin covers on the crank in tack and good shape?

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guitarromantic

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Bearings are really sloppy side to side but zero up and down play. What do you mean by tin covers Im sorry I have no idea. Im not very comfortable with the idea of splitting the cases myself so I havent pulled the crank out yet if what youre asking requires that... I will measure cylinder but most likely going to have to replate anyway. Where do you think the washer came from?

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Kirkes

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In the service manual, there is a spec of side play on the big end of the rod.

The two crank halves O.D. Are cover in a then metal we call tins. They are to cover up the hollow spaces in the crank. This keeps crank columned down help with prof romance.

I to would split the cases.

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Grand Master

LovingOffroadPain

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Okay thanks everyone. I will keep this thread updated once I get everything apart.

 

Holy 

 

Definitely split the cases I had some metal in my 250 when I bought turned out to be part of the crank but the motor was locked so I couldn't see it since it was on the bottom📎ImageUploadedByThumper Talk1402856052.171940.jpg

 

Holy balls and toasted crank bearings!!!  That picture is amazing.

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Experienced

Kirkes

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In the service manual, there is a spec of side play on the big end of the rod.

The two crank halves O.D. Are cover in a then metal we call tins. They are to cover up the hollow spaces in the crank which keeps crank volume dow and increases throttle response.

I to would split the cases.

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KTM_Pat

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Definitely split the cases I had some metal in my 250 when I bought turned out to be part of the crank but the motor was locked so I couldn't see it since it was on the bottom📎ImageUploadedByThumper Talk1402856052.171940.jpg

Done this twice so far myself with my '97 cr250. Shattered Both with hot rods cranks. It happens when you over heat from long WOT.

Remember to replace your crank seals and bearings when you order a new crank.

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BigDaddy94

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Done this twice so far myself with my '97 cr250. Shattered Both with hot rods cranks. It happens when you over heat from long WOT.

Remember to replace your crank seals and bearings when you order a new crank.

yea, I rebuilt the bike 2 years ago and put all new bearings and all so it's still raising hell that's just a picture I took when I first bought the bike and began tear down
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  • 4 weeks later...
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guitarromantic

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So I dropped off my motor to a friends relative who is good with motors and is pretty much doing this to keep him occupied. He took this picture and said he cant find anything wrong with it, and that the pieces he found werent of a washer but cast aluminum. But from where? When I did the top end many rides before any of this happened I was fairly certain I did everything correctly and torqued properly but he speculated that something from the top end or carb got sucked into the motor. Unfortunately money is a bit tight for the moment but am going to be making good money soon. Should I just put new gaskets and seals in for now and send my cylinder in for a replate and do a fresh top end? Or should I save up and buy a complete rebuild kit for the $500 or whatever? Id prefer not to use a wiseco crank if I do... let me know what you guys think. Thank you for reading and your input!

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KTM_Pat

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Posted (edited)

So I dropped off my motor to a friends relative who is good with motors and is pretty much doing this to keep him occupied. He took this picture and said he cant find anything wrong with it, and that the pieces he found werent of a washer but cast aluminum. But from where? When I did the top end many rides before any of this happened I was fairly certain I did everything correctly and torqued properly but he speculated that something from the top end or carb got sucked into the motor. Unfortunately money is a bit tight for the moment but am going to be making good money soon. Should I just put new gaskets and seals in for now and send my cylinder in for a replate and do a fresh top end? Or should I save up and buy a complete rebuild kit for the $500 or whatever? Id prefer not to use a wiseco crank if I do... let me know what you guys think. Thank you for reading and your input!

Well I have no clue where that could have came from. I could say it came from the piston but it should be obvious. Or you had that scrap hanging out in you air filter and got sucked in. I have no clue and would love to know where it came from.

I would definitely dig deep and cross your t's before your next purchase. And if does turn out everything is good. Just get your engine and cylinder gaskets and replate the cylinder and new piston. I wouldn't rebuild the whole thing. Well given money is tight.

Edited by KTM_Pat
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Grand Master

Beau 88

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Okay so when I opened it up those metal pieces were sitting right on top of the crank. The piston looks fine to me, so I am confused. Can someone tell me please where those came from? I have the engine off the bike now, what do you all think is the best course of action? Cylinder replate, top end, new crank (not wiseco or hotrod) and..... ??? Of course theres probably more than meets the eye and the bottom end needs gone through and flushed out as Im sure theres tons of metal and god knows what down there. Anyone with any worthy/encouraging advice to help me through this mess is much appreciated! I just wanna get back to riding...

That last pic looking into the bottom end , something contacted the case in the top left ,  ?

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