Scott E Posted July 8, 2020 Report Share Posted July 8, 2020 My barn find MT-11 had some Harley Davidson mufflers that were on it that were simply too loud. I have ordered a 2 into 1 Dnepr stock type exhaust for it. I've gotten extremely tired of wearing ear plugs because those aftermarket Harley pipes not really mufflers. Just open pipes with fish tails fabricated on the ends. In frustration I fabricated an exhaust for it using 1 1/4" EMT conduit, a 1" NPT coupler cut in half and machined to fit the end of the pipes, 2 short 1" nipples, and 2 Briggs & Stratton part # 392989 mufflers. I had to expand the EMT conduit tubing about 1/32 of an inch so it would just slip over the muffler pipes that attach to the heads. I then tack welded the machined 1" NPT pipe couplers to the other ends of the conduit pipes. I then screwed the mufflers on the 1" short nipples and then screwed them into the adaptors on the pipes. I used 2 1 1/4" conduit hangers to support each of the the pipes where the large muffler loops would normally hang the stock mufflers. I was successful in that I can now ride my MT-11 without ear plugs. It's significantly quieter than it was. What was surprising was finding an improvement in engine operation. I guess the engine performs better with a little exhaust back pressure. I thought those 2 "Lawn Mower" type mufflers might decrease performance but they are working perfectly fine. They are rated for engines between 9 and 16 HP. My MT-11 is rated at 32 HP so one on each pipe equals 16 HP each. That's how I convinced myself using them would work, and they did. They cost $9 each at Tractor Supply. I kind of wish I had tried this out before ordering the Dnepr muffler. It's more than just satisfactory until I get the stock type muffler delivered. Quote Link to comment Share on other sites More sharing options...
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