I think the "strength" concern would be more of a "precision and wear" concern. If the bolt up is even slightly sloppy, the 4 teeth on either side of the 'seam' in the sprocket would not have the same spacing between them as the rest, which could throw off the contact position for quite a few of the other teeth that engage after that one. Not the end of the word, but (as with running a new chain on a worn sprocket) it could wear out the chain rather fast.
I'd guess this isn't an issue for go carts partly because they run very heavy chain compared to power, and partly because they don't see much milage. Then again, maybe its just not an issue, or stops being an issue once the chain "seats" to whatever slight irregularity the bolted up ring has.
I say go for it, but keep a close eye on chain stretch.
If you just want two different ratios that are easy to switch between, maybe you could do something equivalent to a
dingle cog? That is, side by side sprockets front and back, such that both combos (inner and outer) use the same chain, but different ratios? Could easily go +2/-2, maybe more. Not sure if that's really practical on a motorcycle though.