Thoughts, musings, and frustrations in the pursuit of perfection. In short, complicating simplicity.

Tuesday, March 1, 2011

So the latest bike I bought was from  a "Master Machinist", and it was his baby, so you would expect thing to be in fairly good order.  When I picked up the bike it ran well enough, no strange noises, no bangs or chunks, nothing out of the ordinary, which is to be expected since he said he rebuilt the motor 300 miles ago.  So I tear into it the other day and found this:

Evidently Mr. "Master Machinist" could not put a wrist pin clip in properly and destroyed both the cylinders and pistons, to the point that I don't think over boring will save them.  They will probably need to be re-sleeved.  Awesome!
BTW the pictures make it look better than it really is.

This is why I do a complete tear down and rebuild of every motor, and so should you.


  1. all I can say is WOW! What did mr. master motor builder say? Did he claim that you caused this? Isn't that the usual answer? Well it was okay when it left. For the not so knowledgeable, why didn't it make any strang noise?

  2. luck or the wrist pins werent quite worn down to create mayhem. YA a rebuild requires frigan wrist pins...good grief.

  3. I think not putting the clip in would have been better, then you just have the pin bouncing around,and the cylinders could have been saved.

    I think the guy rode it enough that it wasn't making noise when we picked it up.

    But all is good that ends well. Thanks to Adam it now has a 750 big bore.

  4. well, that sucks. That year didn't need wrist pin clips. They're clips...clips are gay!

  5. They defiantly are overrated. It is my understanding that they were a factory performance option until the mid '70's.