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So I received a YZ125 that somehow has a chunk of the left crankcase half missing at the rear where the swingarm pivot goes through. This may be a stupid question, but I just wanted to see if anyone has ever had an issue replacing only one case half? (ie: issues with bearing bores not lining up perfectly from batch to batch)
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People will say no but it should be fine .
Just another wannabe who makes some videos from time to time
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nearly all case sides are matched together from the factory.
If the holes on each side are not line up perfectly you will destroy crank/crank bearings/transmission bearings and the cases again.
if you have the missing piece, just get it welded.
Just a roadracer sucking at motocross.
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If cases are matched they wouldn’t sell them as separate part numbers..
Yamaha sells case halves so he will be fine.
Plus I can assure you, if you buy both halves they are not coming “matched”, your getting two random parts.
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From personal experience on a 05 YZ125. Put a hole in the left side case from a clutch push rod issue. Replaced just one half. This was done approximately 40hrs ago, no issues. You should be fine by just replacing one side.
IG - @rwchaulk
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I have replaced quite a few case halves in my life and never had an issue, and also why they sell them as halves and not one "kit"
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4DAIVIPAI2K5 wrote:Husky only sells as a set for the 65, as they are match bored.
The OP has a yz125, manufactured by a company by the name of Yamaha.
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Location: Sparks, NV USA
Not sure if Yamaha does it, but I replaced a left case on my cr250 last year and it came with new bearings already in it. Saved me a little money since I only had to order bearings for 1 side.
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Have done it many times, no issues.
Engineering, Quality Assurance, and quality control should rank very high at any of the major brands I would think. i.e. I don’t think they are just hap hazardly producing individual case halves that don’t match up.
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4DAIVIPAI2K5 wrote:Husky only sells as a set for the 65, as they are match bored.
If my grandmother had wheels she would be a bicycle.
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Location: Sacramento, CA USA
Can’t speak on a YZ125, but I replaced only one side of my KLX110 cases and it’s been going strong since 2009 lol.
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You can match them for surfaces when you get the other case 1/2, I have done this many times. Just bolt them together empty, with case dowl pins installed, tighten case bolts. Now inspect all mating surfaces, base gasket, intake tract, ect. to make sure everything matches.
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Next time you have a two stroke bottom end apart, sit them together and look into the crankcase and see how well they’re matched; there’s your answer, they’re not. Not a problem buying YZ125 cases separately.
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Yamaha sent me both halves when a recall on 450 rh crankcases was happening. I was curious and compared old/new halves - the cylinderbase height was not the same. So they knew that for a proper repair both halves are needed. If only replacing one half I would at least measure the positions of all the bearings to avoid trouble later. Nothing destroys a bearing faster than any amount of offset. Of course you could be lucky and everything matches but in the long run the other half is probably way cheaper than missing a couple rides and having to tear the whole thing apart again and need a couple more parts which the misalignment destroyed ...
