THE MOMENT OF TRUE.

dcarver220b wrote:

Any possibility that crank journal has been ground down to smaller diameter for the bushings you found in place?

Then replaced with OEM, leaving too much clearance?

Just thinking back to my r69/s crank that someone had done that too..

Fortunately, my smart engine builder caught it..

I don't know, my friend.

When I installed the rod bearings they looked tight and the engine hasn't run long enough to wear out the shaft.
I will disassemble the engine this weekend.

At the moment my youngest son has removed all the flammable liquids I had in the shop to keep me from being tempted to set the fucking bike on fire.

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This Saturday afternoon I locked myself in the garage with Christine to disassemble the engine.

I used the old hoist I installed a year ago to pull the engine out of the chassis.
 

Seeing the amount of shit accumulated in the oil pump filter screen, I already sensed that the thing did not look good.

 

By disassembling the lower part of the engine block and accessing the damaged connecting rod I could see the problem.

(I still can't upload videos, I leave the link)

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On disassembling the rod end I could see that the bearings had overlapped when they came out of their housing.

 

The connecting rod bearings have looked like this after about 60 km, maybe an hour of engine operation.
When I first disassembled the engine over a year ago I found exactly that problem, overlapping and worn connecting rod bearings.
THIS IS THE PROBLEM WITH THIS ENGINE.
I then ran my finger over the crankshaft crankpin and noticed uneven wear, taking measurements with the caliper did not match when changing angle.

 

Next week I will go to a machine shop and see if the crankshaft journal can be refilled and reground to size.

In the meantime, I will try to investigate where so many metal flakes are coming from, whether from the crankshaft bearings or some other added problem.

 

I feel your pain.  Sorry to hear you have to go through this again.

Ive never heard of a bearing spinning and stacking up the half shells. Something is really wrong for that to happen. Normally, there's an interference fit between the bearing shell and the conrod bore of between  .001" to .002" plus the locking ears on the bearing that fit the notches in the conrod bore to lock the bearing halfshells in place.

You need to verify oil flow to that journal as part of your investigation. Could be a blockage in the crankcase supply or a blockage in the crankshaft supply ports. There's a flow chart in the service manual that shows the oil flow path.
There's also 3 different sizes of Conrod bearings available based on markings on the crankshaft. That info is in the manual as well.
I would never replace conrod or crankshaft bearings without plastigaging the clearances. I believe that procedure is in the manual as well.
I'd also look at the filings with a magnifying glass looking for sharp edges or balled up aluminum, or copper from the babbit bearings. Also try using a magnet to see if it's iron / steel particles. It may help point you in the right direction.

You've had your time with this one, but hang in there. Once you get this one fixed, you'll have quite a few stories to tell and be a better man for it. Just take your time and check, check, check.

Video Assist


...and damn.. KawaBcn is fearless. I would have found a chain and drug that bitch down the road.

Just Kidding, but I don't have the skills or equip to pull engines...

Keep going, we are cheering you on!
 

Just wondering, what are the chances all that metal circulating has caused other issues?