Looking for left crank case 08 yz450f

9 replies to this topic
  • rideracelivemx7

Posted July 26, 2014 - 06:03 PM


Hey guys, i got a smoking deal on an 08 450 thats in great shape. However, the old chain snapped, came forward and broke the case that holds the clutch rod(hence the great deal on the bike). to my understanding this is a common issue on these bikes? any how, im dying to ride this thing but cant find a case on ebay. Anyone have an idea where i may be able to score a LEFT case? plenty right sides on ebay :(

  • drtrcr400

Posted July 26, 2014 - 06:19 PM


They are a matched set and need to be replaced as such.

  • rideracelivemx7

Posted July 26, 2014 - 09:34 PM


Is this a Yamaha thing? I've replaced other case halfs together before with no issues.

  • drtrcr400

Posted July 27, 2014 - 06:51 AM


Yes it is. Sorry for the bad news.

  • rideracelivemx7

Posted July 27, 2014 - 01:40 PM


No kidding, what makes these case halfs unique so they need to be a matched set?

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  • grayracer513

Posted July 28, 2014 - 06:39 AM


The lower powered engines that Yamaha produces, like the TTR series, you can buy a single case, but they're matched pairs only on any of the high performance models.  This is because, on those models, the YZ-F's included, the final boring of the shaft axes is done with the cases bolted together to insure the highest possible precision. 


What makes them so special?  The attention to the best manufacturing processes, which is one of the things that makes the YZ450 so reliable.


Chains break for two reasons: they either get run for far too long in too worn out a state, or, very commonly, they get adjusted too tight.  With the bike on a stand, you have to be able to raise the top run of chain a minimum of 1.9" above the rear chain slider bolt.  If there is less slack, the chain will draw up taut before the swing arm passes through center, and that binding can break chains, rear hubs, and on some bikes, even a transmission case.  

  • rideracelivemx7

Posted July 28, 2014 - 07:23 AM


Thank you for the info. Would I be alright with getting 2 used lower end halfs or just finding a complete lower end?

  • grayracer513

Posted July 28, 2014 - 03:23 PM


What's the difference?

  • rideracelivemx7

Posted July 28, 2014 - 06:49 PM


What's the difference?

Complete meaning slap the top end on there and run it vs just case halves

  • grayracer513

Posted July 29, 2014 - 06:49 AM


Complete meaning you have no idea what condition the bottom is in, whereas with bare cases, you do?

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