YS 91SR-3DS break in and blow up !?!

[rudyy]

When I break in the YS engine, I richen it up to half more turn than what the manual said and then start leaning it one click at a time until I find the sweet sport.

[LaDon]

I agree with Eric here. 30% didn't kill it. I break all mine in on that percent. I also will agree with him on the fuel. We used to run the wildcat fuel but wat talked into switching to cool power and instantly the motors started running better and cooler. Just our experiences with it

[Ghostrider]

Trust me when I tell you the % of nitro has nothing to do with it. More than likely, this was a rebuilt motor and the and the wrist pin retainer or cert clip got sucked up. If you don't cut the little curly cue ends off of these c clips, they break off 50% of the time and will blow up your motor.

I would bet good money this is what happened. Nothing the operator did, the % of nitro, or the setting of the needles. If you build enough motors, you learn this little trick the hard way.

If you don't believe me, call YS and ask them.

[Arclight338]

I ONLY run 30% Nitro. I own 4 91 YS motors and have never had an issue. Torco 30%,Coolpower30% and Powermaster 30% have worked flawlessly.

All the fuels have a synthetic oil content OVER 20%. Dont blame nitro. Unfortunately, you either learn how to tune properly or you WILL hurt motors. Give them a chance to break in before really hammering them with hard 3D. Regardless of Nitro content,YS seems to like a synthetic oil package and run on the rich side.