BRIAN B. - I wouldn't bother trying to polish the conn rods. The idea behind polishing is to eliminate surface defects which cause stress risers, but hopefully those rods were handled carefully enough to not have any. Polishing rods works good on forged aluminum or forged steel rods that are harder material. Not so well on diecast rods, since they're so soft. You'd problably end up removing too much metal and end up with a weaker rod.
About 18 yrs ago when SON & I were racing R/C gas cars really hot & heavy, we had a failure on the big end of a conn rod, crank pin end of a .129 CID engine which ran around 32,000 RPM. The bronze bushing spun inside the diecast rod. I eventually found a supplier out in Calif. that machined billet rods from good 6061-T6 alum alloy, pressed in bronze bushings, and never had another failure. But I had a supplier visit me at work one day who did "SHOT PEENING", which is another method of improving strength of conn rods by removing surface defects. I had a part made from die cast Magnesium that some customers were breaking. We got off-topic, and I asked the one engineer if they could shot peen a conn rod...ohhh, maybe an INCH long. His face lit up... "YES, We do them ALL the time!." Turns out the R/C boat racers used the same size engine we used but cranked them up well over 40,000, sometimes over 50,000 RPM. The stock conn rods failed half the time and ruined the whole engine. When they peened the rods they almost never failed, but they were only good for one pass, after the first pass 90+% of them failed on the second pass.
Anyhow, my engineers finally found out that "Inter-Granular corrosion" was causing the failures of the mag. part, Magnesium is very well known for that problem, the corrosive cleaners a couple customers used would cause the parts to corrode and you could crush them in your bare hands! A "SPECIAL" coating...(MAN I hate that word "Special") and a press fit stainless steel insert in the bore raised our cost from $40 each to almost $400 each, but fixed the problem. The owner of the co. who made the part was an Attorney, and I almost had him agreeable to let me duplicate his patented part and investment cast them from 316 Stainless steel which would not have needed the coating or the SS sleeve in the bore, making a $200 part, but the engineers shot that idea down. Guess it made too much sense! Why use a $200 part you can get in 2-3 weeks when you can get a $400 part that's almost as good that takes two MONTHS to make?
If you want a stronger rod, I'd look at somebody like Midwest Super Cub who makes machined billet alum. alloy rods then cryogenically treats them. The pullers use them and they're good to 8000+ RPM.
On the frt wheel bearings, make sure the width of the hub of the new wheel is the same as the old wheel, since you need shims on one and none on the other I think the new wheel may be a little wider. You can file or grind the face so it's the same width, but keep it flat. Don't remove too much metal on the ID of the hubs where the bearings seat. I also have to use a steel drift punch to remove the bearings. But they should go in easier than they come out. Just make sure there's NO pressure from the thk 3/8" flat washer under the spindle cap screw in the center of the wheel against the inner races of the wheel bearing. Loser is WAY better than even a little tight.
