Connecting Rod failure and case damage

3 replies to this topic
  • Paewraul

Posted April 04, 2012 - 04:13 PM


Hi guys,

Two things here. I had my mechanic freshen up my motor a couple years ago and I replaced the stock connecting rod (had some pitting) with a Vesrah connecting rod bought through

I have my WR set up as a supermoto and I run her up at the NHMS road course at Loudon NH as my track day bike. This is a true road course and not a "california" supermoto course.

Anyway, here are my problems... My new connecting rod (less than a year old and only a few good rides on it) sheared off right below the wrist pin. The flailing section of the rod poked holes in the inner wall of the rear of both sides of the cases.

1. Has anyone had a connecting rod break like this? Anyone have a similar failure/problem with Vesrah parts? Are they likely to help me out?

2. The rod only poked through the inner case wall and into what looks like a "Trellis" section of the case. It didn't go all the way through. Is there any significance to this void space? Can I have it welded to fix the issue (my mechanic has a very skilled bike welder).

Unfortunately I let her sit for over a year before I addressed the problem. This will likely bite me in the ass now. My good luck always shines through.



Edited by Paewraul, April 04, 2012 - 04:16 PM.

  • YamaJet

Posted April 05, 2012 - 04:30 AM


Based on my experience with Vesrah gaskets and clutches over the years, I would not recommend them. Use OEM.

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  • Joel_D1124

Posted April 06, 2012 - 10:52 PM


The correct fix would be to completely replace the cases with new ones or quality used cases. These type cases are difficult to weld. You can have someone look at them and try to weld and fix them as they are already damaged and you really make them any worse?? It sounds like you have a skilled welder I would just make sure they are experienced in welding cast pieces. If you have significant damage and if this is a track bike of some sort i would consider correctly fixing the problem and replacing the parts completely. I've gotten away with using welds or even jb cold weld on certain cracked cases as a cheap fix but it's never the right fix and often the bike will never seal correctly especially if the crack is near or on where a gasket or plug sits and the bike will most likely continue to leak.

Edited by Joel_D1124, April 08, 2012 - 09:35 AM.

  • Paewraul

Posted April 11, 2012 - 05:58 PM


Thanks Joel,
I have the bike at my mechanic's for this one. He has a skilled welder that does a lot of bike welds. I 'll be sure to check with him to make sure this guy has dealt with cast pieces before. I'm optimistic about the fix because the rod didn't punch all the way through. I don't think the area is close to a seal either. Maybe I'll look into some cases, but I'm pretty low on cash (that's why I had to wait so long to fix).

I am thinking about converting the bike back to a woods bike and selling off my SM parts. She really is nice aside from some teeny tiny holes in the engine. Her days of screaming around the track are likely over.


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