Legalities

[Scottymac]

So I've got my exhaust system pretty much sorted and am very happy - delkevic header and collector package with Beowulf end cans ( I need to get up some photos !) . But I've left out the dB killers and think it sounds awesome - here's where the sticky bit is - how loud is too loud legally ? 

[Hooli]

Legally you can't modify it to be louder than it left the factory. The frame plate tells you how loud that is, 98db I think off hand.

Guess how many people bother about that...

[gsxbarmy]

What Hooli said plus its the fact that with the DB Killers out, yours is no longer a certified can, so technically illegal on the road.

From a loudness POV, it's down to individual police who may stop you. If they think it's too loud, then they can issue you with a ticket to get it sound checked at your local MOT station, and then produce the certificate that it has been tested and meets standards.

Having said all that - it has to be a jobsworth copper who does that.

Personally, having run my 14 with both the baffles in and out of my Beowulf Triovals, I always found that mine ran better with the DB Killers in......

[Andre]

The frame plate on my K2 says 88 dB(A) at 3400 min (exponent -1), assume that's rpm.
You can easily find out what yours is by looking at the frame plate, it might be different.

[T 24]

The rules depends on where you live Scottymac. You didnt mention it.
In Finland 5 dp over frame plate is allowed in Euro 1 bikes like my K2.
In my frame plate is 88 dp, so 93 dp is allowed. My first trial in inspection was just a little over 93 dp, so I made little dp killers and the next trial was OK, 92.5 dp.

[grog]

no baffles is the go, i reckon here you could be booked no matter what you have, even stock. keep it loud. put a harley sticker on it, they a horrible loud and seem to get away with it. worst sound in the motorcycle world. imo.

[Mick_J]

I think Harleys are the best sounding bikes, by far, followed by Ducati and 60's British twins with 360 cranks.

[Tony Nitrous]

Cops here have tightened up on loud pipes.
Normally in high crash / fatality area's as a bit of deterrent to the high numbers of bikes there.

One of my bikes was originally plated / complianced at 90db.
I have aftermarket cans and have had it retested at 94db and a new sticker fitted.
(Cops seem OK with up to 5db over here)

My other bikes, including my 14 aren't legal.
Around here they'd need to be within 5db of stock and be tested and tagged as such.

5bd over is loud enough for me.
Sound is measured in a logarithmic scale so for exmple, 5db on 100 isn't not a 5% gain. It's a lot higher.

[daveh]

I remember reading once that Harley's sound louder because they are, the reason for this is the note is deeper on a twin and I think it means the sound travels differently.
The science is beyond me but I think it's something to do with a bass sound wave being longer, so when you hear the doof  doof car go by the bass is louder on the footpath than in the car.
I think.

[grog]

sorry MJGT, just over the sound of hardlys, past my place with no baffles, backfiring, so loud rattle glasses in cupboard. not sure how they enjoy riding. couple of dukes go past, lovely sound. very loud gsxr1000 goes past, very nice. the nicest is mine, of course not really, the nicest is a mv brutale with open pipes, amazing.