You won't find a lite weight 4-stroke for cheap. But you can go with a magnum 4 stroke. They are almost half the cost, but do weigh a couple oz. more than the saito's. The run great and will run fine on 10% fuel. They really don't see much more performance on higher nitro anyways, like saitos or ys's do.

I have about a gal of WILDCAT ys20/20 run through my Saito 82a and see about 9100 when set 300 rpm rich of peak. I'm turning a 15X4W apc. I'm told the rpm will increase as I run a couple more gallons of fuel through it. It has increased about a 100 rpm from a half gallon to one gallon. Some others told me you shouldn't consider a saito broken in until about four gallons. This is my first four stroke so I rely heavily on what other modelers tell me.

You should be able to fly the plane with your 82 after only about 40 minutes of break in. You are only restricted to 4000 RPM for about 10 minutes after that just keep it a little on the rich side. I leaned my bottom end quite a bit after about 30 minutes and then went flying after 40. I considered it broken in but didn't fly it too hard or get it too hot. I didn't notice any significant difference after that. Maybe just a tiny bit and I leaned the bottom end some more. The Saitos are always super rich on the bottom and can stand quite a bit of leaning out. That's where you'll get the better mileage, by leaning the bottom end.
This is a honey of an engine. I use it in my UCD, well at least I did until I sold it to a young man in our club for $70. But to sweeten the deal I threw in a couple of props and a landing gear he needed. I presently don't have this engine. But I've put a lot of time on it and love it. It flew the UCD sweet!!! Well, until gjeffers convinced me to go with a 100. I'm still building that plane.
Thanks,
Barry

9100 is pretty good.... My ST G-90 swings a Pro-Zinger 10K on 5% - I knew that 82 was strong...

Thanks Razor,

I was concerned with the 9100 and wondered if I should drop prop size back to a 14x4W in order to get the RPMs closer to 10,000. I believe I'll stay with the 15X4W for a while to see if the engine speed increases with time. Like I said, I've flown 2 stroke engines for about three years so I'm used to the higher RPMs albeit smaller props. My history is Norvil 25; OS 40; Several Magnum 46 XLS ; and a Magnum 52XLS. I tend to lean toward the Magnums as they perform great considering their price. Considering what I've heard and seen, I must say this Saito seems like a really good engine so I may convert a HOTS that the 52 is on over to another FA82a. Thanks to all for your imput.

after having run 2-strokes for 12 years, i recently purchased my first 4-stroke, a saito 82. I have noticed that the throttle response is faster then 2-strokes. Although they might not spool from 5k to 17k as quickly as a 2-stroke (because they dont spool that high), i feel that they can rev from 15% throttle to 100% throttle much quicker then a 2-stroke. The power also feels much more useable for 3d because you have that torque and throttle response there in an instant. The strokers feel a little weak up top, where the 2-strokes seem to keep gaining more and more power as they rev. So basically, i think both motors have different power bands and therefore each has advantages in different situations.

Well put Ange. I think the Magnum may be the way to go for the time being. what size would i want for something like a Mojo 40? 91? thanks guys!