Back to the original question, even a plain jane starter built for 60 size helis will crank a monster engine as long as you connect it to 2 R/C car packs that allow the battery to dump the amps faster than any lead acid or gell cell ever can. Even my really old sullivan hi-tork (non dynatron) can turn a 80 or 90 as long as your battery is fully charged. If not, the r/c car packs will do the trick.

Right now, I'm using a Thunder Tiger hi torque airplane starter, just because it was easier to mount r/c car packs to it compared to the sullivan starters. Plus, everybody on the field uses my starter since it's now cordless and it lasts a whole week on a single charge.

As for the YS80, I still prefer it to the OS91, no lean-out all throughout the flight even with low fuel, smooth, consistent and requires less needle adjustments as is usually needed with OS depending on the weather. Once OS gets a better carburator on it, I would've been willing to try it, but the YS91 is just around the corner so... duhhh.

I've had 20 gallons through my setup with NO rust, and I only changed the plug ONCE after the 12th gallon. I always use Magna (a.k.a. CP30%) on it and it gets really soaked with oil after a good thrashing around in the sky.

BTW, I am also using the stock throttle barrel as I haven't experienced the alleged "burp" some have mentioned when transitioning inverted as I prefer to keep the GV-1 off to save fuel when doing 3D.