E: Engine Exhaust butterfly valve?

Howard

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To prevent boredom during lockdown, I've been doing jobs on the Comet that needed doing and some that didn't need doing, including fitting some bits I removed from the Egli when I detuned it, including Mk2 cams, which we all know won't work right with a silencer. Unfortunately, the straight through silencer I fitted is a tad on the loud side.
Before I start reinventing the wheel, has anyone fitted a butterfly valve to deaden the exhaust note - it might come in handy when passing horses in Peak District lanes.
The previous exhaust was pretty loud, and the bike backfired when shutdown, which left me with 2 wrong choices when I saw animals on or near the road.

H
 

erik

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backfire or detonation is when there is an air leak in the exhaust system.I would check the connection in the cylinder head first.Erik
 

vibrac

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I did this many years ago
no mater how I arranged it the gas flow would open it or sometimes even close it at the most inopertune moments. It would work the cable and the choke lever I employed unless it was too tight to move.

A rotating barrel with matching holes would be a way to try
when I had a AJS 7R on the road (What a great year that was!) I would stick a foot over the exhaust pipe end if I wanted a bit of quiet (just as I was coming home late with my push bike lights) a long stretch but I was young but the boot got hot!
 

Oldhaven

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In my youth they were called Snuff or Nots, and were made by Pacifico. My best friend from high school and college used them on his open piped Honda 305 scrambler that I would borrow to see my girl friend in the next town. I think you would need the S-50 size, but they are nearly as vintage as me and our Vincents. They are not remotely controlled though.

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Oldhaven

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I just found a parts diagram. The clever cupped washer and spring was what kept it in position at 90 degrees. Perhaps this can be used remotely if you want to make your own.

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Bill Thomas

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I don't think there is any point, My BMW K100 made no noise, Only a whine, And it still spooked them.
 
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