where are you driving the roller from?
or should i say, hows it attached to the shaft?
looks like its just a bar, drilled, with a nut up the end?
1, no out rigger bearing. the pressure you apply the the roller bends the shaft, places huge loads on the bearing, and tends to rock flywheel back and forth on shaft til its flogged out then pop.
remember it will be bending back and forth over 100 times a SECOND!
2, thrust. when you tighten the roller or nut it forces the flywheel harder onto the shaft. is it tapered or parallel? i think its parallel. theres no face for it to press against unless it has a shoulder, which i cant see... all that stops it is the bearing. designed for radial, not thrust loading. the other bearing inside the engine also experiences a thrust loading. any play, deformation or bending will upset it.
thats just what i can see? obviously i didna make it!
but things ive learnt with friction drives is to support the roller on bearings. one on either side of the tyre. then apply the pressure to this frame, not the engine bearings. leave them to support just the crank! attach motor to this frame too, obviously
self aligning flange/saddle mounting bearings are ideal and easy to use.
ive only ever bolted a roller directly to the flywheel ONCE. ever since ive always used some sort of flexible coupling between roller and crankshaft. plate with two holes and corresponding pins, etc... commercial options are lovejoy or helical couplings. try fleabay under "cnc coupling" for an idea...
or think about the cushdrive in a motorbike rearwheel
when i look at the new engine you have... okay, use a 1 1/2" washer, say. drill two holes on opposite sides, say 1/4". you place this washer on the flywheel, and drill a tiny 1/8 hole real close to the shaft, through washer, and into flywheel. hammer in a lil bit of 1/8 welding rod or something, to "key" the washer. when you place the nut on, either use a washer or dril this pin hole so the nut covers it and holds pin in place.
thats your "shear" pin. it will break before anything! maybe use two or a thicker rod... no more than 3/16!
now, you have a drive dog pinned to the flywheel. it will spin with it, and the flywheel nut holds it all on. theres no more load on the assembly than when used as intended
get your bearings and mount em to a frame so they straddle wheel.
HINT. use (order lots of, so easy to replace
) 5/8 ID star washers for the roller! and order 5/8 ID bearings! then a simple 5/8 bolt long enough to go through the lot! if its high tensile it might be ground and really accurate with a nice fine pitch thread with a nylok nut
also, ensure the shank of the bolt is long enough to ride on both bearings! eiether space bearings to suit or use washers under end nut, but do not run the threads on the bearing race itself!
then you have to make another "dog" from another 1 1/2" washer, weld bits of bar into the 1/4 holes for teeth so they engage with washer on flywheel. place washer behind bolt head, assemble bolt, star washers and bearings, tighten, then weld washer to bolt head. you may need a spacer or two between washer and bearing to clear things. grind back bolt head for min clearance and shortest "dog teeth" as possible.
use the thickest, widest washers you can find that are a good fit on the shaft!
alternatively, use flat plate and drill all the holes, etc... whatever works.
flexible coupling finito and never experience flywheel failures again
then you just gotta mount motor to bearing frame in line
and you should be able to do it all at home with basic stuff
the star washers? they have way more grip than a plain shaft, they can be flipped and reversed on the shaft when worn, they high tensile so dont wear much at all, and the OD is around 13/16 which is the PERFECT roller diameter on a 2stroke
also very cheap
