Seized connector rod


7 replies to this topic
  • apt

Posted February 21, 2010 - 07:14 AM

#1

Well,I GOT THE BIKE TAKEN DOWN A BIT NOW AND HAVE FIGURED OUT THAT THE LOWER PART OF THE CONNECTING ROD IS SIEZED TO THE MAIN BEARINGS. THE BEARINGS ARE PURPLE ISH WHERE THEY TOUCH THE ROD. OBVIOUSLY THE BEARINGS AND THE CONECTING ROD SHOULD BE REPLACED. I PLAN ON DOING THE TIMING CHAIN, PISTON AND RINGS, AND ALL SEALS/GASKETS. MY QUESTION IS , IS THERE ANYTHING ELSE THAT I SHOULD REPLACE OR CHECK OUT SINCE I WILL HAVE THE WHOLE BIKE APART

  • grayracer513

Posted February 21, 2010 - 12:21 PM

#2

First,

Posted Image

Second, the blue color on the crank at either side of the connecting rod is normal. It happens as part of the manufacturing process, and they all look like that. If the rod were seized, it would be either difficult or impossible to move, or rough and loose feeling. Third, the main bearings are the ones the crank rotates on.

In answer to your question, yes, there are some things you should check out: everything. Check the trans, all the bearings, fill the ports with solvent to check valve sealing, everything.

  • apt

Posted February 21, 2010 - 02:45 PM

#3

ok bro. obviously the caps upset u for some odd reason. i am not good w the computer and it takes me a long time to type things so less is better for me. the lower end of the rod is definitley siezed. i will take ur advice on the solvent as i have seen that in the manual. thanks and sorrry about the caps.

  • grayracer513

Posted February 21, 2010 - 05:25 PM

#4

obviously the caps upset u for some odd reason.

Reading a message typed in all caps is the equivalent of being yelled at. It's annoying, and generally considered rude.

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  • ThumperKid250F

Posted February 22, 2010 - 10:44 AM

#5

ok bro. obviously the caps upset u for some odd reason. i am not good w the computer and it takes me a long time to type things so less is better for me. the lower end of the rod is definitley siezed. i will take ur advice on the solvent as i have seen that in the manual. thanks and sorrry about the caps.



if you think the blueish color means its siezed then your wrong.. everycrank looks just like that..

just my 02

  • Birdy426

Posted February 22, 2010 - 12:34 PM

#6

To expand on what Gray said...the connecting rod never connects directly to the main bearings. It rotates on a pin that connects the two crank halves together. It is normal for the crank halves to be blue/purple as they locally heat that area to assemble the crank. Does the connecting rod rotate on the crank pin? If so, it's not siezed. If not, it is. Does the crank rotate in the case? If not, a main bearing is siezed. If it does, the mains are not siezed. None of that means they're "good", just not stuck.

What model and how old? How much of the history do you know? If I was not the original owner, I would replace every bearing and seal in the cases while I had the cases split. They are fairly inexpensive if you go to a bearing supply house (Motion Industries or equiv) and have them match what you take out. There will be a few they can't match, but oh well. Definately do rings while you have it apart, but measure everything and replace piston, cylinder, etc as appropriate. If it's a 400 or 426, I wold get the 4th gear magnafluxed as there used to be a few reports of failures. Inspect the shifter forks for wear and replace as required. Everything else is pretty well accessible without pulling the motor or splitting the cases.

  • Birdy426

Posted February 22, 2010 - 12:35 PM

#7

If you are working on a 400/426, you will probably find that it's more economical to replace the entire crank than to have yours pressed apart, replace the rod and bearings, and reassembled/balanced...

  • DEEMOTONUTT

Posted February 28, 2010 - 06:47 PM

#8

I have a simular problem on my spare 99 400 bottom end. The rod is almost seized to the crank ( will not rotate without force ). Can I run a 450 crank,rod and top end ? Or just go with the 426 set-up. What are some of the tricks you can do to the transmission i.e. BRP shift fork etc.

Thanks TT peeps,

D





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