110 with no Muffler?
 

I have a 110 that has got 3/4 of a gallon through it now.It has been running great.I have not leaned it past peak yet.I have been running it at 9500 with a 16x6 APC.Today the back half of the muffler fell off and I lost it.I refueled and fired it up again and now it spins at 10,200.I richened it up to get 9600 and flew again.Besides being a lot louder it ran great.
Is there any problems besides noise, running it without a muffler?
Is 10,200 too much?I did not think it could spin a 16x6 that fast.
This is my first YS.It is a very impressive engine.:D

RE: 110 with no Muffler?
 

It won't hurt to run without the muffler. Try one of the new APC 16.5x5 props, it should pull the rpm down a little. 10200 is at the top of where you ought to run it, so no worries.

RE: 110 with no Muffler?
 

I run my YS 91 without a muffler, and it's fine. I'm using Graupner 15X8 prop, YS blend 30% nitro and I get 9,800 RPM. My 110 runs on 15% and a 16X8 APC and gets 9,800RPM with no muffler. Most larger 4 strokes don't like to be run over 10,000 RPM, so prop to what your engine will turn as close, but not over that. The nice thing about the YS is the fact it's pumped, and charged. Though they do like to burn glow plugs (probably because I use the pig prop at max throttle), and they can get finicky with fuel pressure. Remember you need to use the header. It's what ports the exhaust from the head, and is designed to scavenge it from the exhaust port. The muffler only quiets the exhaust note, and really serves no other purpose. You just can't beet the power of the YS! That's why I love them so.