I have an OS 160FX with a Bisson muffler and I have a cowl on the airplane, but the tubes need to be extended to clear the bottom of the cowl. The tubes come within about an 1/8" from the bottom of the cowl and not where the bottom of the cowl is already cut out. I really don't want to hack up the opening any more, so can I bend the tubes somehow and add extensions onto it? Or would it be best to cut to Bisson exhaust tubes down and add the extensions so I can angle them back to exit the hole in the bottom of the cowl?

Easiest way is to go to your automotive parts store, and pick up some heater hose. Also, some hose clamps.

> Jim

No, don't try and bend 'em.

Now there's a good idea. Thanks

Get the stuff that's red on the outside, and black on the inside. Been using them for years.

> Jim

Sounds good, do you think it would make any difference in output pressure or anything if I cut the exhaust stacks down an inch or so and added about three inches of the heater hose? Like I said in the post, I have the bottom of the cowl cut out and need to angle the exhaust out the hole without making additional cutouts.

I had to plug one of my Bisson tubes for reliable OS 1.60 running. I'm running a 24oz tank, without a pump, and was not getting enough backpressure to richen things up suitably. Plugging one of the tubes did the trick. The stock muffler only has 1 output tube, and the 2 tubes on the Bisson was not providing enough restriction. You may notice that on the Bisson, the tips of the tubes are beveled over to create more restriction. In my particular case, this was not enough. If you need to run your needle out more then 2 turns to richen it up, then I would suggest plugging one of the Bisson tubes. Try it first and see ?

My OS 1.60 now performs beautifully.

> Jim