I have a CG Ultimate Bipe. Last week, I ordered a Magnum 91 four stroke engine for it. Today, I bought a TT F-91S four stroke for a price that I did not want to pass up. Which engine should I use for the bipe? I am new to four strokes and to both of these engines.

Thanks

It Doesn't make much difference on those two

They are birds of a feather,six of one,half dozen of another.

Sell em' both and buy a Saito or OS...

AJC

The TT is more powerful but does require a lengthy break-in. Main needle: 4-5 turns out not 2-3.
The Magnum will get you up and flying sooner with less break-in and power.