What motor should I get for my next build? I've been getting pk80s, they're pretty good, but how would a phantom 85 compare?
I've had a wildcat pk80 for a long time. Abused it, holding it wide open, 9k rpm, running it lean, putting timing in it, nitro, whatever (not all at once). I've never had a catastrophic failure. The main thing that happens to it is cylinder scoring, which I'm not really sure why it happens, but whatever. It doesn't vibrate much, always starts up fist revolution without choke.
I've now had two phantom 85s have catastrophic failures within 30 miles. One of them the ring caught the exhaust port and ruined the cylinder and piston. Bottom end was fine but the holes drilled into it for the studs where crooked and wasn't useable. The second one, which blew up yesterday, the piston tore itself in half (see pictures). The bottom end is full of piston bits and metal shavings. Might be saveable but the case surface was extremely uneven as well. Both my engines would rattle my teeth out at 6k rpm.
IF you get a phantom, you NEED to tear it down, balance the crank, replace the bearings, surface the cases, put an aftermarket chainsaw piston in it, and clean up the ports. Even if you do that there's no guarantee that the holes will be drilled straight in the case, a piston ring won't snag, or some other weird factory defect. Sure, the thing will absolutely rip, especially if you put something like a pwk carb and pipe on it, but it's not worth it. If you want speed, just get a minarelli.
I don't know what their reputation is and I don't want to get in trouble with damien, but southerncustomcc has a prebuilt minarelli with a preadapted mz65 pipe for $450. After what I've been through and wasting so much time on this junk I'd much rather spend the extra money on that minarelli.
(Venting ends)