WLA Smoke from oil tank

[KNUCK]

Odd how a piece of your piston broke off, from photo it does not look like a "burt" piston. After tear down you need to measure the cylinder, maybe just a good hone job will allow you to put in another set of 0.50 pistons and not bore. If cylinder is scored then that will require boring. You said only 2500 miles so let us hope for a hone solution.

[BigLakeBob]

I would think that after only 2500 miles there would be honing cross hatch marks still on the cylinder wall.

[dukekleman]

Sounds like you have piston and piston ring issues...
Testing and removal of the engines cylinders will reveal the problem.

As suspected from what you stated was going on...
Note the location of the piston failure in relation to the exhaust valve. During engine development this is a classic sign of temperatures elevated to high. The causes were caused by either fuel quality, fuel quantity, air quantities or excessive ignition timing. During your rebuild, be sure to verify the items listed. One item listed will be difficult for you to verify at the road speeds you originally posted when this failure occurred. There is special equipment for this that most people aren't going to have and/or a chassis Dyno. By the seat of your pants, which is what most have for an option, be sure to go a little bit richer for lower temperatures in the combustion chamber. I hope this helps you resolve your problems to get you out riding again.

[Jerry Wieland]

Odd how a piece of your piston broke off, from photo it does not look like a "burt" piston. After tear down you need to measure the cylinder, maybe just a good hone job will allow you to put in another set of 0.50 pistons and not bore. If cylinder is scored then that will require boring. You said only 2500 miles so let us hope for a hone solution.

I do not think a piece broke off. It looks to me to be burnt as in too lean of a fuel mixture or an air leak.

[T. Cotten]

,,,, The causes were caused by either fuel quality, fuel quantity, air quantities or excessive ignition timing. ....

The most common cause of all, Folks,..

Is the evil manifold leak.

Did you test it properly, MK?

(You didn't use a tire pump, I hope. Or a test plate with a Schrader valve.)

....Cotten

[KNUCK]

Get that piston out and let's have a good close up look at it please.

[mkynaston]

So I got everything apart. And it appears that the valves on my rear cylinder had been relieved and the ones in the front (with the melted piston) had not. I ordered a new set of v-twin cylinders to replace them. Should I take them to a machine shop to have the cylinders honed and the valves relieved before I start reassembling?