I took my daughter dirt biking to Caineville with some friends last weekend. While we were out riding her bike shut off and I quickly realized the motor was seized.
Once we got home I pulled the clutch drain plug to find what looked like pure metal flake in place of the oil. No surprise since it was seized, but I hoped it would be this serious.
I drained the radiators to find them full of burnt looking oil. And when I removed the clutch cover liquid metal poured out onto the work bench. The culprit was the water pump gear. The factory gear is plastic and notorious for breaking. So, being the smarty pants that I am, I bought and installed an aluminum in its place. Well the jokes on me, the aluminum one grenaded into billions of little metal dust specs and infected the entire engine!
I have never seen so much metal in oil before! It honestly looked like spilled silver paint on everything! The metal flakes were so fine they could pack into shapes like putty, but still thin enough it was nearly impossible to completely clean.
With the entire engine stripped down the crank still wouldn’t rotate. My hopes of it just being a top end we’re long gone. I split the cases and found that a small piece of metal had gotten wedges between the case and the crank, bringing it to a halt as it dug deeper into the case. Lucky that piece of metal didn’t just blow right through the case! Then it hit me, why didn’t it get ground into dust like everything else? Because this isn’t aluminum, it’s steel! Where did this bit of steel come from now?
It took me a while, but eventually I figured it out. It was a piece of the bearing cage from the wrist pin bearing! My guess is the loss of coolant fatigued that bearing until it cracked.
I replaced every bearing and seal in the engine, got the proper base gasket figured out, and she’s purring like a baby lion.
I also swapped out her bent exhaust for this Scalvini piece of art. It took a bit of massaging and ingenuity, but I think it fits pretty good now.