Tuesday, October 12, 2010

Rincon 680

 I finally got back to work on the Rincon 680.  I pulled the top off the engine and discovered that the cam is wore just like I suspected. 

I am still not sure why it wears out?  In the first photo you can see the cam sitting in the "tin bathtub" full of oil.  It is definitely getting plenty of oil.  There was no noticeable wear on any of the other parts.
Here is the cam and followers removed from the engine.  You can see the follower on the right has a definite concave shape to the contact surface, it should be flat.  Both the intake and exhaust lobes were about .075" short.

I don't know why this is happening, but it seems to be a common problem on this engine.  An after market cam is available for about the same price as a new Honda original part.   I am going to recommend that to the owner.


  1. With the follower and cam worn, it seems unlikely to be a cam specific issue. It seems like somethign is wearing both parts down. It seems unlikely that both the cam and follower could be defective / soft.

    Based on that, could this damage indicate that there is a problem with some abrasive in the oil? Is it possible that this engine is somehow getting sand in the oil that is getting to the cam before being captured by the filter? Disecting the filter might prove or disprove this. Is there a breather system that might be sucking dirty air in? There is certainly no shortage of sand in Brevig if it was sucking dirty air.


  2. I wonder if the problem is related to the way that the cam is lubed? When I took the engine apart there was some crud in the bottom of that tin pan. Maybe the contaminates in the oil end up in that pan and can't get out? There is no outlet on the bottom, the oil overflows out the top.

    There was no noticeable wear on anything else?


  3. Hmm, sand in the oil would wear everything, not just these parts. Perhaps a problem with the oil passeges might be the issue. If it isn't a dirty / plugged oil passage, is it possible that there are oil passages that weren't properly drilled at the factory resulting in poor oiling of the cam?

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