How to silence your Jota pipes?

Bert Reganze

Bert Reganze

Junior member
Location
Leiden NL
How to silence your Jota pipes? Why would you? Too loud when driving slowly in the city? Solid sound at higher revs is appreciated very much ;)

Just look for a (near) perfect fitting pipe/tube and fix inside at the end of the Jota exhaust see picture.

I found these ones:

https://www.praxis.nl/badkamer-keuken-wonen/meubelen/meubelpoten/duraline-meubelpoot-rond-chroom-3x30cm/6536038

Tested with a dB app on my smartphone, pipe 25cm long. Also tested 30 cm, same results but engine becomes less crisp

at idle 1000 rpm -8 dB, that is 8 times less experience in sound!
at 2000 rpm -3 dB
at 4000 rpm almost no effect

Ciao

 

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Basically you extended the Helmholz-Tube and benefitted from the Helmholz-effect.  ;)

When I had my bike with the German T?V for getting the additional HP, the GSX-R rims and some other mods entered into the papers, they told me to muffle the silencers as they had a hard time to accept the 111dB it put out...  :D

I got some dB-eaters made with 32mm outer diameter. They were basically tubes, closed on one end, with only some (!) holes in it. The sound was massively reduced, but the bike did not really produce any power anymore... I called the exhaust man to ask what I can do about it and he said I should simply drill more holes into the tube. I started drilling but with my home equipment, it was simply not successful...

I simply removed them after I got home and never fitted them again but would be really interested in getting some proper ones made...
 
My neighbor's kid is learning to play the Trumpet, I put up with that. They put up with me going riding every couple of Sunday mornings.
 
I concur - Never heard wiser info on how to silence a Breganzie - ROFL !

Other then; check if the baffles are still in the pipes; Breganzie's have a tendency to spit them out.
I had to pay repairs for my neighbors car door when a Breganzie Exhaust Baffle suddenly ejected.
My Breganzie may have enjoyed it but I didn't ;o)
 
keep up Ron, you have not been paying attention for the last five years have you?
Jota silencers do not have any baffles, what you see is what you get, just the skin and that three inch long tailpipe in the centre of the end cap.
CLEM
 
my chain saws are much louder than the mini bikes my kids had 35 odd years ago, but when the neighbours complained about the noise the kids and their bikes were making, I asked the kids to stop (which they did) and I started sawing logs, closer to the house, much more noise and fuck 'em. This house was built in 1956 and I am the second owner, the first one was into bikes as well, so there have always been bike noises at the house, children and grown men, as I did and still do, today an American import Honda 150 farm bike was being run up and down the drive, lasted all of two lots of ten minutes and then done, if they don't like it, that's tough I was here first (me now 40 years) they bought a newly built gin palace 18 years ago, and paid ?1.800.000, if they think they can influence my not unreasonable behaviour then they had better think again, but fortunately they are aware and tolerate me, much as I do them. with their constantly yapping all day and night dog, and their VERY loud garden parties in the summer. I offered them 25 off street parking spaces one year when they had a party, but when 100% of the car drivers/owners totally blanked me as they drive past me to the areas agreed, I never did it again, the lady who did the catering, both knocked on the door before she parked and afterwards, carrying bottles of wine for me from the "leftovers", she can come any time she likes, wine or no wine.
CLEM
 
Hi folks,

This topic was intended for the guys who were interested in getting the Jota exhaust more silent. I appreciate that a lot of you guys are not interested in doing so.

Its a pity that a topic like this gets contaminated by so much negative comments and other rubbish.

Thanks for the guys with positive feedback. But I am confused now which effect is meant, Lothar?
 
I am kind of with you in wishing for quieter  pipes than the stock Jota ones, I even obtained some original Lanfranconi stock silencers, I fitted them and the bike (1200TS) was a lot quieter but was hugely strangled at all throttle openings, especially low down, swapped back to stock, admittedly, I didn't do a jetting swing, which might have helped, I just couldn't see it would make that much difference, there are clever people out there, we just need to get a proper technician involved to design a baffle system to fit inside the Jota pipes but create no, or very little resistance to "go"

Paul Haynes, Professional industrial automotive exhaust design specialist, YOU ARE VOLUNTEERD
happy holidays still cant find me coat.
CLEM
 
Wasn't really a negative comment as a tongue in cheek comment hence the  :P sign.
But seemingly you've decided its not the thing to do, question your irrational question.
  As stated the world's sweetest sounding exhaust note WHY?
answers on a postcard to,
Mr a irrational.,
        3,cylinder drive.
            Queitsville
     
Merry Christmas 🤶
Regards Andy 😁
 
Bert Reganze said:
But I am confused now which effect is meant, Lothar?
Click to expand...

Hermann von Helmholtz (background see: https://en.wikipedia.org/wiki/Hermann_von_Helmholtz) did some studies about resonances and their effect on sound and noise. The "Helmholtz Tube" is an invention based on these theories and finds itself in the back of the Jota mufflers f.e.:

A tube that goes into a resonance chamber makes parts of the sound-wave go straight through and some are reflected at the end of the chamber and produce a counter wave before they also go through this tube. This - ideally - makes the two waves cancel each other and reduce noise dramatically. dB-eaters are using partly this effect from my point of view in combination with the drilled holes to achieve this over a wider range of resonances. The effect is widely known as the "Helmholtz-effect", which I referred to. It is also used in other applications where ever sound needs to be modified.

That is at least what I remember from someone explaining me the way the Jota silencer's design shall work. If you compare the different cans offered in chromed steel and in stainless, you will recognize that the chromed ones mostly have this tube going into the muffler, many of the stainless ones only have a tube that is welded to the backplate of the muffler. The later ones typically sound more aggressive and harsch while the ones with the tube protruding into the muffler sound more rounded and with a lower noise overall. Agree?

The length of the tube defines if higher or lower notes are cut out (or are reduced to be more precise...).

See the video for more information:

https://www.youtube.com/watch?v=y221-Fzib_w

HTH
 
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