This can't be good...

I noticed I was leaking oil from the above the clutch area, so I pulled the carbs off and saw this:
http://i826.photobucket.com/albums/zz18 ... NoGood.jpg

Two questions: 1) What is that? 2) Is it fixable, or do I just need to replace it?

 

That's the cam chain tensioner.

Does it have a crack in the casting? I think you need to replace the casting as if it failed and the cam chain lost tension, the result could be catastrophic!

 

That is the cam chain tensioner. Replace it before you even start that motor again. Never seen one fail like that before.

 

I'd almost wonder if the chain was fluttering against the blade so much it slapped the tensioner around rapidly in there and hammered that casting.

Been hearing any rattle from it?

 

Now that you mention it, I have been hearing quite a bit of rattling from the area. I read a few posts about engine noise and just assumed it was normal. I guess that was a dangerous assumption. Anyway, I just ordered a new tensioner off ebay; should be here in a few days.

 

More than likely it failed like that because somebody overtightened the crap out of the tensioner retaining bolt.

I hate to be the one to tell you this, but you may need more than just the tensioner itself.

The tensioner pushes against a long curved chain guide (fiche: http://www.babbittsonline.com/pages/par ... fault.aspx) and if that has come loose and gotten torn up you'll need to get it replaced too. If it's just been rattling and bouncing around you may have gotten lucky.

DON'T just install the tensioner and hope for the best. Pull the valve cover, and get in there with a flashlight and inspection mirror(s) and have a look at it. The good news is, you don't have to split the cases to replace it. The bad news is, you DO have to pull the head and maybe the jugs to replace it.

If the chain guide is ok, then you're good with just the tensioner. Look in the fiche and ensure you have all of the tensioner parts and they're in the right order.




The part indicated by the arrow is a "dampener" it's a washer that's rubber on one side and metal on the other; the smaller spring presses against the metal side, the rubber side goes toward the larger plunger.

Note the small o-ring up by the adjusting bolt; that goes under the washer for the locknut and keeps the tensioner from leaking oil at the bolt. Be sure to replace the gasket and that o-ring on the eBay tensioner you got.

 

Before you pull that part off read the manual on setting the tension you will want to set the motor up first. Also when you get the replacement part file off the indentions where the bolt has indented the shaft on the plunger look at the pic Big provided see the two marks .

 

Hopefully the replacement won't have such marks gouged into it. If tightened to the correct torque, it hardly leaves a mark.

It's amazing how few people actually use torque wrenches.