Frank2's Manco "Death Machine"

[Frank2]

I had this mini bike for the last 18 years and decided to finally replace the very tired 3.5hp engine with the very common Predator 212cc. Then things snowballed out of control and I started modifying it because the 72 tooth rear sprocket basically made it a wheelie machine, and practically unusable (hence the name death machine). On to the pictures.

How it began:

Old engine removed:

Ghetto exhaust, when the master link gave up on life:

New exhaust, with removable muffler, (the PBR can didn't last) waiting for the 54 tooth sprocket and new chain:

Waiting for my package of Mega Jet kit, new spark plug and OldMiniBikes muffler to come in the mail later today.

Future plans include billet rod, flywheel and to remove the governor in that order of course.

 

[chipper]

Nice start Frank , those are nice riding bikes !!

 

[OND]

Nice Frank . :thumbsup: I bet it did pep the old girl up !

 

[S_C's KID]

I have one of these but a tad less threatening, awesome build will be cool I'm sure :thumbsup:

 

[owend]

Good start, my last one Manco was really scary with a Honda GC 160 and a TAV!

 

[Dr. Shop Teacher]

Yessiree! My 'Bird became known as "Death Wish" after I put a GC160 on it and kept the 80 tooth sprocket. Once I changed the sprocket down to 54 teeth it became much more rideable!:doah:Was a nice little bike but way too small for my 6'4" chassis. Good luck!

BTW, be sure to look at stiffening the motor plate or that Pred is going to twist it off. I made a flex plate that bolted to the underside of the motor and allowed for chain adjustment (See Manco Budget Build).

 

[Frank2]

Thanks for all the feedback!

A few updates:

1/2" EMT conduit is not an ideal exhaust material when its not properly braced apparently...

I broke a couple chains and couldn't figure out why.

Then I saw this, Oops.

More "robust" 3/4" rigid conduit exhaust

 

[Dr. Shop Teacher]

Ooooh, you definitely have to do something with that motor plate. That predator will break any weld you do to fix that tube. You might want to look at boxing the whole plate with 3/4 angle, slotted for the engine bolts and welded to the cross tube on either side of the break.

 

[Frank2]

I was planning on using 1/2" angle on the outside of the plate to stiffen it up, but I certainly like your idea much better. Thanks!

 

[Dr. Shop Teacher]

I was planning on using 1/2" angle on the outside of the plate to stiffen it up, but I certainly like your idea much better. Thanks!

I'll be interested to see how it turns out. Since I don't have a welder, I made a flex plate for the front of the engine and used the block to prevent twisting. With that break--and I gather that was from the time with the 3.5 hp--that certainly wouldn't work.