Hello all. I have a situation that I never really even thought about till I had to rebuild my Saito 65fa. I have been putting together my 82" Great Planes Cub ARF and realized that the timing might be off on the Saito. sitting on the shelf was a bright shiny OS .91 four stroke. YES... I know... it would be way over powered. There is a 3 ounce difference in the engines and they are the same length. I need thoughts and advice. The only worry with the Saito is that I will have to send it off to service to adjust the timing cam. That is the bad thing about rebuilding a four stroke. So what are the thoughts on putting a 91 in the Cub?

I would go with the .90. You may have to enforce the firewall, add the smallest prop for the .90 as per the manufacture, reset the cg and adjust the carberator to not open past the 3/4 mark, or you can adjust the trottle setting on your radio.

My opinion.

I have a saito 62a in my Cub and it's perfect. Save the money and time your saito.
http://www.lismoremodelflyingclub.or...tes/saito.html

I made the tool suggested and it works like a charm.

I would re-time the Saito and use it. It really isn't that difficult. Remove the rear cover, remove the push rods, loosen the cylinder enough to raise it up so you can get the push rod tubes out, mark the rods and tubes so you can reinstall them back in their original location, bring the crankshaft up to Top Dead Center, I think there is a mark on the crank gear that should be pointing straight up, hold the cam cover and rotate the camshaft so the dot is pointing down and reinstall the cam cover. You will need new gaskets for this but it isn't all that difficult to do. Readjust the valves and you should be ready to go.