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My CRF250R seized

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Well, it happened. Piston seized (oil ring pinched in the cylinder). Rod broke, and tore a hole in my case and the cylinder. I blame my own dumba$$ for not doing a top end sooner. I have the piston kit in my garage ready to go, but I was too lazy. My bike has around 70-80 hours, and I promised I would do it at around 50. Oh well, live and learn. Hello, Service Honda, I would like to order a shizload of parts from you and have them shipped out to Hawaii 2nd day. Why yes Mr. Antman, no problem, that'll be around 700.00. Ahhhhggg!!!!!! Oh, and the track had to be tacky and perfect and I blew it up in the first hour. At least I didn't wreck. I was landing a step up and getting on the gas when it just stopped instantly. I almost went over the bars and my feet were in the air. A last second clutch grab saved me. I guess it wasn't all bad luck. :cry:

PS My head is OK and my valves are in spec. :cry:

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Look at that cylinder real close, I'm willing to bet that the front lower sleeve portion is cracked or broken? I do not know why you would experience a pinched oil ring after 50+ hours of riding especialy if it's the OEM installed part (you never had the cylinder off?), but if the cylinder sleeve failed it would set off a chain reaction. I thought I had a broken piston on a CRF250 at my shop but it turned out the sleeve cracked and broke first. This is not uncommon and I've heard Honda may be standing behind some of these? You may have too many hours but you never know...

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I would also bet that the cyl. skirt breaking first caused the "chain" reaction. When this happens it usually takes out both case halves also. If you do have to replace both cases, get the '05 s along with the '05 cyl.

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The piston skirt was NOT cracked and cylinder was cracked a little, but right where the rod broke through, so I'm not sure if it was cracked and caused the problem, or cracked because the rod punched the hole. The oil ring slipped out of its groove on the piston. The rod, wrist pin section of the piston all broke loose. The rod then punched a hole in my cylinder and case. The front side skirts of both the piston and cylinder appear to be damaged by the broken rod. Larry, thats a good idea to go with '05 parts. Whats the differences? I already have an '04 top end, piston, rings, wrist pin, etc. Will this all work with '05 cases and cylinder, or should I get an '05 piston as well?

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The piston skirt was NOT cracked and cylinder was cracked a little,

MXA reported that the cylinder skirt (not piston skirt) is prone to cracking, and show a picture of the condition in the Oct issue, pg 134.

The '05's are supposed to have stronger cylinder skirts....

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yep, 03 YZ250F. Engine totally fubar. Notice the cracks in the piston under the pin.

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As I understand, the cyl. skirt is thicker henceforth the cases are machined for the larger/thicker cyl. I think everything will interchange internally, but I don't know for sure. I am tearing down two new engines this week to completely modify and I will post back if I see any apparent differences.

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The '05 cylinder skirt is the same diameter as the '04. It is not thicker, but it is slightly shorter (4mm). There are a few different transmission parts, so you need to be careful about what will interchange in the cases.

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I can't get '05 parts yet so I'm just getting '04 parts and a lot of them. I will be doing my top ends twice a year instead of once a year from now on. Thing is this bike was strong. I wasn't getting blowby or oil consumption. I WAS on the rev limiter though (Preparing for a landing). I won't be into the rev limiter as much in the future. Oh, well, stuff happens.

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