BBK THAT DIDN"T CUT IT By Alleyoop (Read 772 times)

[Alleyoop]

Here are pics of a GY6 bored out case to except a 63BBK. Notice the thin walls by the Bolt holes and the side of the Cam Guide(paper thin) and missing a piece of the side wall.
Alleyoop

[scatterbrained]

Yep that's exactly what not to do! That case and jug should never been paired up. Not engineered for that kind of stress. I wish them the best with a new motor.

[cyborg]

ouch,,who did this build?

[cdoublejj]

these failed BBK posts make me happy that i'm only boring out 6xcc and using tweaked stock parts. (real hot rodding)

[jct842]

It would be really nice to have the powers in china to re-engineer the gy6 and design it to hold a 200cc jug. The 150 is what a 110cc motor? Any way at 150 it is borderline for stress and heat yet still works well/ And a 50cc motor is as close to bullet proof as they come.

[clonedrone]

Not enough information to come to a conclusion.
Was there a stroker crank part of this build?
Considering if the case boring was a perfect circle off Center? Note how thin on one side and not the other.
Looking at the case bore job alone several measurements should have been taken before final assembly.
Looks like the cylinder flange thickness is around .035, this is absolute Min. thickness.
I dont like to go below .039 unless a sleeve is cast in a cylinder.
Neglected to ask if a stock cylinder head and gasket was used? Squish would be stock bore side and the piston most likely hit the cylinder head.
From the looks of the sloppy Permatex job alone looks like a all around Butcher Job!

[mxmatt]

I'm starting to think that any BBK is not a good idea. Are there any kits out there that are worthy and won't overhead a stock GY6 150?

[clonedrone]

Feb 21, 2014 12:36:24 GMT -6 mxmatt said:

I'm starting to think that any BBK is not a good idea. Are there any kits out there that are worthy and won't overhead a stock GY6 150?

They are what you make of them.
The little GY-6 has plenty of room for a few more reliable hp.
All I see are fundamental's overlooked leading to failure.
I have to say the ole "IF I had a dime for every wrench who does know how to install a circlip" Yup Circlip!
Put the Craftsmen down and slowly back away from the Scoot.

[tvnacman]

That was a 63mm I sell a 61mm and still needs to be bored out . I bet a torque wrench was not used .

Al I hope that was not your engine .

John

[forcefed44]

That's quite scuurrrryyy..

Chris
Black Art Bikes