I really am leery of all these big bore and turbo aftermarket mods. It is well known that the 912 80 hp engine is longer lived than the 912s 100hp with its bigger bore. Rotax deliberately used the 80 hp bore when they added the 914 turbo, rather than the 912s bore to keep engine stresses down with the added pressures of the turbo.
You should know that a 650cc Rotax powered quad is much more affordable that an 800cc. This is good for the person who would be interested in a big bore kit, because the bottom ends, and transmissions are almost 100% identical. The 650 has slightly lower gearing. This is great for Rhino’s due to the extra weight of the vehicle.
Scooterpartsco.com Malossi 72cc Big Bore Cylinder Kit for Yamaha, Minarelli  - Malossi's most popular 72cc street kit for Yamaha and Minarelli 50cc Two Stroke Engines. Very reliable, durable, and built to outlast the original parts.
Dec 18, 2015 · I do not have a super charger just the 116 Big Bore. I will have one eventually when I buy a new bike later I will have the Vision torn down rods installed and add the super charger. Halfcrazy is correct there is a ton of difference in high teens torque and high 120s. It will smoke the tire at will and thats just snapping the throttle.
The AMS EVO X 2.4L Big-Bore Crate Engine is the ultimate solution for high horse power reliability. Their crate engine comes complete from valve cover to oil pan to timing chain and components to make installation as painless as possible. This package uses only the best products we sell and comes ready to drop right into your EVO.
The next few hours should see the jetting optimized for the new larger displacement Big Bore Rotax/Hackman leaner/GRT EIS combo , in the meantime I'm flying about every day. Right about the time the dust settles on all these changes, my 78" Prince Prop will arrive, to stir things up some more.
Since I'm looking to Big Bore most of these older different engines, I may be limited to, 62mm, 67.5mm, 69.5mm, all to a 72mm Big Bore, and 72mm, 76mm, to a 78mm Big Bore, and 78mm to a 82mm Big Bore. So I may need only a 72mm, 78mm, 82mm, inserts. But I will probably do the stock bore sizes down the road also.