jim.mt10 Posted June 21, 2019 Report Share Posted June 21, 2019 Hi, fellas After a long and tedious fight with the authorities to get permission to put my Dnepr on the roadhere in Switzerland, at one point I was told it would be 100% impossible, it looks like I've found a loopholeand they might let me test it, ALL I have to do is take it to the Dynamic Test Centre (sounds expensive...and it is) and have them check the sound level with a stationary and drive-by test. I'm going to put some thicker oil in it and maybe make some temporary baffles for the exhaust (it has the KMZ pipes with flat ends) The bike is pretty quiet, but the noise level in the factory handbook says it should be not greaterthan 86 dB and for it to pass the test it has to be no louder than 80dB. I just thought I would ask if anyone has any tips on how to make it a bit quiter, my nightmare is that I spend the money and it's 1 dB too loud. Thanks for any suggestions. Ride safe (and quiet) Jim Quote Link to comment Share on other sites More sharing options...
racepres Posted June 21, 2019 Report Share Posted June 21, 2019 Ensure the Intake side has an "adequate" filter... Intake noise is real as well as Exhaust... Which is easy... 2: 1 and good baffles... Quote Link to comment Share on other sites More sharing options...
dowey Posted June 21, 2019 Report Share Posted June 21, 2019 Nitemare Jim ..80db is always going to be hard to get but there are apps for the phone that'll give ya a meter so you can get an idea where you are ..then just play with settins an baffles ...good luck mucker :) Quote Link to comment Share on other sites More sharing options...
3 bike mike Posted June 21, 2019 Report Share Posted June 21, 2019 Maybe i talk rubbish but can you put some form of fire proof insulation in the exhaust as well ? this sort of thing https://www.ebay.co.uk/itm/UK-610x300x50mm-High-Temperature-Ceramic-Fiber-Blanket-Thermal-Insulation-Pad/392301547872?hash=item5b56fe9160:g:qwwAAOSwuahc5j2gTake it out again after as it may restrict power Quote Link to comment Share on other sites More sharing options...
Vance Blosser Posted June 22, 2019 Report Share Posted June 22, 2019 Amazon.com has decibel meters cheap. You could do your own checks and modifications before spending the big bucks. Quote Link to comment Share on other sites More sharing options...
dowey Posted June 22, 2019 Report Share Posted June 22, 2019 I downloaded "Decibel X" to my phone and went out to the Ural to see what it said ..it went up into the 90s (i do have louder pipes on mind lol) ...i think it's a great toy but i'd do as Vance suggested and get a proper one with a wand and do it properly. The meter was also sittin in the 80s with normal noise around me like wind ..though i took it into shelter to test the engine noise ..hehe love my new toy :) Quote Link to comment Share on other sites More sharing options...
jim.mt10 Posted June 22, 2019 Author Report Share Posted June 22, 2019 Thanks for the replies, Yeah Dowey, I'm gonna try to borrow a dB meter.From what I can tell, they do a drive-by in each direction and take the average, so I suppose the sidecar's gonna help reduce the average, I think engine noise is louder than exhaust note, so not sure baffles willhelp much, just asjust the valves as quiet as possible and put 20/50 oil in it. I'm waitin for them to send me a date. Ride safe Jim Quote Link to comment Share on other sites More sharing options...
RussN Posted June 22, 2019 Report Share Posted June 22, 2019 If you have a gear-driven alternator, disconnect it for the tests!Might help lower the sound level.~RN Quote Link to comment Share on other sites More sharing options...
racepres Posted June 23, 2019 Report Share Posted June 23, 2019 If you have a gear-driven alternator, disconnect it for the tests!Might help lower the sound level.~RN Oh My Yes... Didn't thing of that... may be even worse than intake noise.. Human perceptions are Not what the "meter" picks up... Quote Link to comment Share on other sites More sharing options...
dowey Posted June 23, 2019 Report Share Posted June 23, 2019 great idea Russ :) Quote Link to comment Share on other sites More sharing options...
RussN Posted June 23, 2019 Report Share Posted June 23, 2019 Russian Bike riders say: "Loud gears save lives."~RN Quote Link to comment Share on other sites More sharing options...
jim.mt10 Posted June 24, 2019 Author Report Share Posted June 24, 2019 Excellent, Russ I hadn't thought of that either. Today, I took a spin past the Test Centre and they were running a test, you can watch from the mainroad. They were testing a car. They have a speed-trap, and drive through it, to ensure 50 kph ( in 3rd gear). They have 2 microphones about 10 metresapart and drive once each way and take the average, so sidecar will be a help. I'm just taking the alternator out at the minute and I'm going to put a sheet of polystyrene in the sidecar (maybe gain 1/2dB)every bit helps! I'm actually feeling slightly optimistic for the first time. Still waitin for the date. Thanks again for suggestions. Ride safe Jim Quote Link to comment Share on other sites More sharing options...
racepres Posted June 24, 2019 Report Share Posted June 24, 2019 Contrive a way to "aim" your hand held DB meter of choice. To Identify "problem" areas. Quote Link to comment Share on other sites More sharing options...
RussN Posted June 24, 2019 Report Share Posted June 24, 2019 Jim:Hope it all works and you get licensed!Looking forward to hearing good news.RN Quote Link to comment Share on other sites More sharing options...
jim.mt10 Posted June 24, 2019 Author Report Share Posted June 24, 2019 Thanks, Russ Might not be for a few weeks, but I'll definitely let you know. Quote Link to comment Share on other sites More sharing options...
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