I need a ( That was Stupid ) button

I have this small folding bike which i was thinking of mounting a friction drive weed eater engine to .

The motor is from a weed eater i don,t need any more , so i strarted stripping it down .
after stripping off the unneccesary parts , i reinstalled the front cowl ( which houses the recoil start )

COOL ... LETS START ER UP . ( Why is it so hard to resist starting them up ? )

Poured a bit of gas in a soup can , dropped the hose and filter in , primed it till gas shot out the return hose , and fired er up .
Ran great for about 1 minute .

CLUNK ... Dead stop ... WTH .

I pulled the rip cord a few times ( man thats spinning kinda free )
then i noticed the actual crank wasn,t turning ... again ... WTH .
I tore it apart again and realized that :

IN MY HASTE , I HAD FORGOTTEN TO PUT THE SPACER BACK ON THE SHAFT .

What had happened was the flywheel had come loose and spun , resulting in a sheared off key ( cast into the flywheel ... not a seperate key )

Press ( THAT WAS STUPID ) button now .

Luckily the seat for the flywheel is tapered , so i was able to put it back together ( without a key ) and it works fine . ( but i should really repair the key )

SAFETY NOTE :

I was very lucky .
Very lucky the flywheel didn.t wobble into the pickup coil and explode the flywheel itself .

THAT ONE LITTLE SPACER , could have resulted in the flywheel exploding in my face .

So anyways , lets learn from this STUPID mistake .

Next time i will lay out all the parts on a nice "clean piece of cardboard"
and sort the parts accordingly .

well unless the used an aluminum key . There is no keyway cut into the flywheel itself .
no little waffer key

it is sheared off to clean aluminum . there was only an aluminum sliver left in the keyway on the crank . ( its a taper seat , the taper is " supposed " to do the holding .. not the key ) and fortunately the seat in the flywheel or the shaft didn,t get damaged or scored at all .

I personally don,t like that design after having to totally tear down my yamaha Roadstar , when the magneto flywheel spun loose from the shaft ( go figure , the magneto shaft only comes out from the inside of the engine ... and its the first part to go in , and the last part to come out ) . 5 years and "who knows how many" shafts later , Yamaha , just out of the blue decides to ad a key to the shaft .....HMMMM ...
I repaced the shaft and magneto with the newer updated version ( since the added key was the only difference ) .

My guess is that the flywheel key was formed on a forge .
They would do this for 2 reasons :
1- to create a harder seating surface
2- to cut the time and cost of putting in a key