New owner of US90 & ATC90

[spork1o1]

I picked up a pair of old Honda's to use for ice fishing. One was a running bike the other needed some parts.
The running trike is a 75 ATC90 and has low compression.
The second trike is a 72-73 US90 and needed a rear axle, rims, tires, hubs.
I took the parts from the 75 and put them on the 72-73 (tank, carb, axle, brake drum, hubs, rims/tires)
The 72-73 runs great for being 38 years old.

I just acquired the needed parts to put the 75 back together, and have done so. But with the low compression its kind of a dog.

I am probably looking at a top-end rebuild for the 75.
What is the bast way to go about doing this? Hone and re-ring, over bore .5 mill, or go with a big bore kit.
Does the 110 have a larger stock bore, or was the stroke longer. If the bore is bigger will the cylinder, piston from a 110 bolt on?

[Mr_RPM]

go with the first size over piston from Honda and bore to that size (i forget what size over it is, i could look it up if needed) its the cheapest and best way for your money. so go with the first option you said. big-bore kits would probably be more money and i doubt it would still be made and you would wanna find it as "NOS" (New old stock) if you went that route. as for the 110 top end im not sure but then your looking at some custom work, cause i dont think everything will bolt up like magic, which to me means to much work and not as trustworthy/dependable. if it was mine i would do it the right way and buy the new over sized piston from Honda, because if the OEM lasted this far then replacing it with another Honda piston would seem to be the most solid way to do this.