How To Identify a 426 engine


9 replies to this topic
  • MNellis

Posted July 14, 2007 - 05:27 PM

#1

I've got a line on a YZ engine and I wanted to know if there is an easy way to externally identify the 426 engine from a 400 or 450.

Will a 450 engine fit an '00 426 chassis?

  • jbrooks26

Posted July 14, 2007 - 06:28 PM

#2

You may be able to tell pretty quickly by checking for the manual decomp mechanism. There will not be one on the 450 motor. However, if someone has upgraded the exhaust cam on a 426 motor it may not have the mechanism either, rather it may have an aftermarket decomp lever plug. This is not fool proof either though as many 450 owners replaced the stock plastic plug with a higher quality aluminum one as well. A better way would be to get the engine number off of it and run it by the Yami shop to see what they say. This is going to be the only way to know for sure I think. Hope this helps.

Josh

  • meyermetal

Posted July 14, 2007 - 06:34 PM

#3

At the base of the cylinder it shold say the cm3. As in cc's

  • MNellis

Posted July 14, 2007 - 06:51 PM

#4

At the base of the cylinder it shold say the cm3. As in cc's



Right, I forgot about that.

Does anyone know if the 450 engine will fit the 426 frame without modifications.

  • shanedut

Posted July 14, 2007 - 08:06 PM

#5

It may fit in the frame but i would think that the motor mounts might be different especially the one on the top of the motor. But i dont know for sure.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • jbrooks26

Posted July 15, 2007 - 01:34 PM

#6

I do believe that the upper motor mount is different. I remember someone saying that you don't have to remove the upper mount to remove the cam cover on the 450, I know you have to remove it on my 426 and it is still a tight fit. Can't say for sure about the lower mounts, but if you have the resources to make your own mounts then you can probably get away with it. The only other obstacle I can think of would be whether or not the air box boot would line up properly.

  • MNellis

Posted July 15, 2007 - 10:29 PM

#7

I do believe that the upper motor mount is different. I remember someone saying that you don't have to remove the upper mount to remove the cam cover on the 450, I know you have to remove it on my 426 and it is still a tight fit. Can't say for sure about the lower mounts, but if you have the resources to make your own mounts then you can probably get away with it. The only other obstacle I can think of would be whether or not the air box boot would line up properly.


Good points, thanks for the commnets.

Mike

  • grayracer513

Posted July 16, 2007 - 07:23 AM

#8

The biggest deal breakers will be the fit of the swing arm bolt and the width of the rear hard point. This needs to match up first. However, the engines are equipped with removable sleeves at that point, and in the worst case, you can remove the originals and modify them or fabricate some new ones to effect a fit.

Next would be the position of the mount tabs under the engine, but those could be cut off and relocated on the frame. Beyond that, the front and top mounts may have to be fabricated, but it's just a matter of cutting out plates. The 450 cylinder head is some 7mm shorter overall vertically than the 426, so clearance isn't likely to be a problem at the top tube.

  • MNellis

Posted July 16, 2007 - 10:12 AM

#9

The biggest deal breakers will be the fit of the swing arm bolt and the width of the rear hard point. This needs to match up first. However, the engines are equipped with removable sleeves at that point, and in the worst case, you can remove the originals and modify them or fabricate some new ones to effect a fit.

Next would be the position of the mount tabs under the engine, but those could be cut off and relocated on the frame. Beyond that, the front and top mounts may have to be fabricated, but it's just a matter of cutting out plates. The 450 cylinder head is some 7mm shorter overall vertically than the 426, so clearance isn't likely to be a problem at the top tube.


Thanks GrayRacer. I can handle the fabrication but the question is, "is it worth the trouble.".

I'm still waiting on the owner to get back to me on exactly what motor it is. I've got a set of 426 cases to replace the ones ruined when the counter balance shaft bearing let go but I was trying to get running again for the least amount of investment.

Thanks again.

  • MNellis

Posted July 16, 2007 - 03:36 PM

#10

It turns out the motor is a 400 so I think I'm going to pass. If anyone is looking for a 400 motor for the asking price of about $425, let me know and I'll put you in touch with the seller.





Related Content

 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.