propstryker

My Feedback: (2)

I purchased and just received a Bisson Pitts muffler for my Moki 2.1. By the way, I purchased it from Graves Hobbies in Orlando, FL, ordered it, they sent it express USPS mail and I had it in a few days. This muffler, as a lot of Bisson mufflers, are pinched at the end of the pipe. Someone said that this is done to reduce noise. I have also heard that it helps increase back pressure to the fuel tank. I also understand that if I cut off this pinched end of the pipe I will pick up a few more rpm's. Anyone care to comment before I install this muffler? Thanks in advance.

DGrant

My Feedback: (4)

Is it pinched, or is it fabricated with a conical tip? It won't make a diff I don't think.I have the same muff system on mine, the tips were cut off the pipes when I got the muff. I put Aerotrend tube extensions and it's been that way for 15yrs. Of course I have a pressure fitting from the muff to tank. I'm sure if the engine is in good shape, you probably wouldn't see any diff on the pipes, cut or not. That engine should fire up very easy by hand as well. I use a chicken-stick with my Moki's, and they start very easy. Really there's no noticeable diff in RPM's.

I don't know what your putting this in, but I do know the 2.10's will run a 22x10 prop respectively in many planes. They are real workhorses in larger glow engines.

warhwk

My Feedback: (3)

Propstryker,
I cut off the pinch on one of my Bisson mufflers and only gained maybe 150-200 RPM's on my 2:10. I ended up with some midrange popping like a mistuned gasser. I much preferred the sound before I cut off the pinch. Definitely not worth cutting off the pinch, nothing to be gained.

propstryker

My Feedback: (2)

Thank you both for your replies. I got a message from Lance Bisson and he told me that he recommends that it is better to leave the pipes stock as it helps with back pressure and fuel flow.