OzVMX Forum
Marque Remarks => Yamaha => Topic started by: ozyditcher on October 14, 2013, 05:08:36 pm
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Will a 1975 mx400 piston work in a 1976 yz400 .
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yes, same motor
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Thanks.
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There are two different rods in those motors, or so I was told.
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piston pin the same size
?
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No same piston , rod and rings , 75 mx400 - 76 IT400 -76 YZ400 -77 Yz400 - 77 IT400 Iain
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Hmmmm, that is a nice development. :)
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one of Yamahas great motors pulls like a tractor will rev with a good pipe and almost bullet proof .
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I got my piston today. Not the same, pin location is off.
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That's what I was told by the Yamaha guys. I will see if I can find out the part #
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What is the piston gen Yam on the original and replacement or one a after mkt
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I did a thread on yamahaenduro.com about the pistons on the 76 YZ 400. One of the guru's on there gave me the info on the two different rods in the motors. My motor has a 214 K rod in it which is the long rod. The superseded part number for the piston is 2k8-11636-00. Another thing I was told is that the piston for this rod should have 51004 or 51005 inside the skirt.
If the piston you have has 51000, 51002, 51003 inside the skirt, it is the other rod. They didn't give me the number on that rod unfortunately.
I was told the rod difference is 5mm and that is why they moved the piston pin location.
I hope this helps cause it had me confused also. I thought they would all be the same but I saw two different part numbers so that is why I asked.
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I got my piston today. Not the same, pin location is off.
Then its not 75/76 , they offset the gudgeon as a measure to help seizures on the exhaust port . No matter the motor runs the same with either
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I did a thread on yamahaenduro.com about the pistons on the 76 YZ 400. One of the guru's on there gave me the info on the two different rods in the motors. My motor has a 214 K rod in it which is the long rod. The superseded part number for the piston is 2k8-11636-00. Another thing I was told is that the piston for this rod should have 51004 or 51005 inside the skirt.
If the piston you have has 51000, 51002, 51003 inside the skirt, it is the other rod. They didn't give me the number on that rod unfortunately.
I was told the rod difference is 5mm and that is why they moved the piston pin location.
I hope this helps cause it had me confused also. I thought they would all be the same but I saw two different part numbers so that is why I asked.
They are all 130 mm , the longer rod came in 79
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Uh OK. I was given the wrong info. :)
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piston pin location has all to do with where the transfer ports are located and nothing to do with rod length or stroke of an engine
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piston pin location has all to do with where the transfer ports are located and nothing to do with rod length or stroke of an engine
yes but the gudgeon pin is wider than the bridge between the transfers so moving it a little one way or the other makes fug all difference.
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I got my piston today. Not the same, pin location is off.
Then its not 75/76 , they offset the gudgeon as a measure to help seizures on the exhaust port . No matter the motor runs the same with either
MY PISTON I TOOK OUT HAS 51004 ON IT . THE MX400 PISTON HAS 51003.
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Do us all a favour mate and call Wiseco to recalland remake all their #232MO8500 pistons that they have had listed for the 75/76 Yamaha mx/yz400 for nearly 40 years. Ta . ::)
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Wossner sells a piston for the 1975 MX 400. However, they don't list it for the YZ 400. They offer 85, 85.5, 86 and 86.5. Retail is $145. We are set up as a dealer with them as well.