[gashousegorilla]

GHG, my valve collets did not pop right out.  The ring was embedded in them so hard that I had to put real heavy pressure on my makeshift spring compressor to get it to pop off the collets.  Again Dave, a machine shop will have a compressor and shouldn't charge more than a few dollars to take it apart for you to inspect.  It takes about two minutes with the right tool.  Try the socket first, it often works perfectly.

Scott

   Yeah, they can be a little "sticky" in there.  It usually take'a a few decent wraps... one will pop, then the other.   And they CAN get a little deformed.  Not a bad idea to replace them as well.  You can pull  them apart, and put them back together in a snap with one of these.......

  http://www.sears.com/craftsman-valve-spring-compressor/p-00947627000P



 

[Ducati Scotty]

I thought about that but ended up using a large c clamp and a piece of pipe.  With as much pressure as I needed I'm sure I would have bent the lawn mower tool. If I have to do it again, I'll lock it in the tool with just a tiny bit of pressure and hit the top with a little torch so it expands and lets go of the collets.
Scott

[AussieDave]

Thanks guys . I cancelled the tools. You just saved me  120 bucks i can spend on the hone . OS piston sounds like the way forward....I wanted to do that anyhow. 
  Once again , great advice! much indebted ,
      Happy New Year All !

[Ducati Scotty]

FYI, they have .020 and .040 oversized AVL pistons in stock and super duper aftermarket forged varieties.  I'm betting the aftermarkets have the better 3 piece oil rings.

Scott

[Arizoni]

And, if no one has mentioned it, NEVER, NEVER, NEVER reuse the cir-clips that hold the wrist (gudgeon) pin in place.

If they are reused, they will most assuredly come loose after the engine is started and proceed to tear up the cylinder wall.  

[Ducati Scotty]

+1.  The heat of the engine destroys their temper and they tend to fail quickly and gouge the side of the cylinder if reused.

Scott

[heloego]

I got an older model of borescope (flat style), but these pistol grip ones work really well, and don't empty your wallet. And, yes, I am a fan of HF. 

http://www.harborfreight.com/high-resolution-digital-inspection-camera-with-recorder-60695.html

http://www.harborfreight.com/digital-inspection-camera-67979.html

[gashousegorilla]

FYI, they have .020 and .040 oversized AVL pistons in stock and super duper aftermarket forged varieties.  I'm betting the aftermarkets have the better 3 piece oil rings.

Scott

  Yes, the forged pistons do have the three piece oil ring and are American made........

[AussieDave]

Thanks for the tips guys . It's been 20 years since I pulled an engine down......
After I cleaned up the piston some heavy scoring was really obvious . I think the avl is the way to go .
Not wise to put the old piston back in in that condition I'm thinking .

[Ducati Scotty]

Scoring on piston or cylinder?  Front, sides, back?

[Roeland]

A bit of scoring on the front and back could be regarded as normal? I had the same on the old piston when I removed it - but the barrel was 100%.

[ace.cafe]

On a piston that has been run in the engine, there will almost always be some rubbing or scuffing marks on the front and rear thrust surfaces of the skirt. These should be very superficial.

The bore might (or might not) show similar marks. If you can feel the scratches with you fingernail,  then they are too deep and need to be rectified by moving to the next larger over bore size piston, and bore/hone the barrel to suit.

 I always hone when changing rings. If you put the same used rings back in the same used bore (assuming they are both perfectly fine) then that is okay. They are already mated to each other.  New rings need a new  crosshatch hone to bed in.
The grit of the hone is important to the type of rings being installed. #320 grit is okay for cast iron rings. #280 is good for ductile iron. #240 grit is good for chrome. 45 degree pattern.
For a stocker, cast iron is okay.
For performance,  a ductile iron or steel or chrome top ring would be preferred. Cast iron 2nd ring is still okay. 3 - piece oil ring is preferred in all applications.

Generally,  you need to set your own gaps and oil ring expander tension, so be advised of that.

[Roeland]

The bike is up and running again. The crankcase had to be split again as it would not turn over properly. It turned out to be 2 misaligned thrust washers on both sides of the gearbox which resulted in 2 damaged needle bearings. Once replaced all was sorted. The bike covered 200 km so far.

[Ducati Scotty]

Good to hear you're back on the road

[mattsz]

Good news, Roeland!

So, in a nutshell for us ignoramuses, what's the takeaway from this?