Piston Questions

[MotorBicycleRacing]

I bought a "modified piston and ported cyl" from a vender here and was suprised that the piston was cut all the way around. Also the "ramps" on the piston were also shaved all the way around too. I figured they know what they are doing so I installed the piston and cyl. Took it for a ride, Way slow, no bottom end at all. Puled the cyl and replaced it with mystock cyl. Ran quite a bit better but still no bottom end. I was also getting a bunch of oil leaking around my exhaust gasket. Today I decided to pull the pipe and look inside. Yep piston at TDC is 2mm above exh port.

here is the pic of the infamous piston that kevo posted on fb.

 

[mapbike]

reshaping the crown may be ok as long as the angle is right, since the deck can be milled to keep compression where it needs to be, but cutting the skirt like that on the exhaust is a big no no.....!!!

 

[BOYGOFAST]

likely the connecting rod journal location is suspect and should actually be moved to each side of of the counter weight the counter centered on the cylinder bore two connect rods one one each side simple one piece crankshaft lighter stronger faster potentially

 

[allen standley]

Did ya get that map?

 

[MotorBicycleRacing]

likely the connecting rod journal location is suspect and should actually be moved to each side of of the counter weight the counter centered on the cylinder bore two connect rods one one each side simple one piece crankshaft lighter stronger faster potentially

You are a flipping genius.
How come no one else came up with that?
Hurry to the patent office before we steal your brainstorm.

 

[allen standley]

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[mapbike]

Did ya get that map?

Yep and as soon as I get my ocean front property in Kentucky sold Im gonna make a serious investment towards some serious R&D on that brilliant crank idea, of course this will also heavily depend on whether or not I'm able to sell my 1 million shares in that 100 year old ice factory in Northern Alaska.

 

[mapbike]

You are a flipping genius.
How come no one else came up with that?
Hurry to the patent office before we steal your brainstorm.

Wow........ I think Im gonna P

 

[MotorBicycleRacing]

reshaping the crown may be ok as long as the angle is right, since the deck can be milled to keep compression where it needs to be, but cutting the skirt like that on the exhaust is a big no no.....!!!

Here's the cylinder that came with the piston.

 

[Davezilla]

Man it looks like this guy spent a whopping 5 minutes with a chainsaw to port that jug... no wonder there's no bottom end with that setup... and what was this guy thinking cutting up the skirt on the wrong side of the piston?
Maybe this guy figured if he "ramps" the pistonnall the way around it would go faster and if you cut off both sides of the piston skirt it would go twice as fast...
I'd get my money back asap...

 

[mapbike]

Here's the cylinder that came with the piston.

Holy crappy port work Batman........!!!!

What a freaking hack job........, that ought to be against the law....lol!

That has to be some of the worst work I ever seen, I would be highly ticked off if I paid for that....wow....!