Supertrapp snuff - $0. [Archive]

AllanB

31st May 2008, 20:45

Well done.
Not wanting to put a downer on it but the WOF standards will now not allow adjustable mufflers. They are fine if the db killer, outlet etc is permanently attached - a rivet or weld is considered permanent a removable screw is not.

Also to shut it up as 100db is very loud and even 95 pretty rowdy. Can you repack it? if so the old packing i most likely blown out.

Buy or make yourself a db killing insert. They work surprisingly well. Easy to make with scrap exhaust tube and you strike me as a innovative chap.

Motu

31st May 2008, 20:54

They have never allowed adjustable exhausts...but the wording had been changed to switch or lever.No switch or lever on a Supertrapp.

Disco Dan

31st May 2008, 21:09

I knocked 5 db off my Supertrapp today - read all about it here.

http://www.advrider.com/forums/showthread.php?p=7087133#post7087133

Great post, I was interested in the last comment though about how having a temporary silencer for warming up early in the morning so as not to wake up half the street.

That way if it was just for that purpose it would not matter what it looked like or how big/bulky it was - the noise reduction would be the importance.

I must admit I have never thought about how an exhust works to silence but I understand it would have something to do with altering the direction of the air through lots of channels rather than a free flow style?

Bearing in mind bikes generally idle about 800-1100 rpm compared to a car which is much lower and only a couple of hundred rpm.

It would also need to be put on/removed easily and quickly without burning your hands or scratching the chrome of the stock pipes.

Any ideas?

FROSTY

31st May 2008, 23:00

AllanB

1st June 2008, 09:12

Yeah this is the bit where you hope you do not get a WOF Nazi who does not understand why the baffle on a two-stroke should be removable.

I had Dunstall replicas on my old 750 twin a few years ago and the core was removable to allow repacking. At the last WOF I was told that the mufflers should fail as the cores were modifiable. I note you can still purchase these mufflers.

I politely pointed out that the purpose of that was to allow repacking and that I had in fact removed them, repacked them with a superior packing AND fabricated an insert into the core to make them quieter! I offered to remove them to prove this if he desired.

He smiled and quietly ticked the box. :niceone:

I've noted that arguing with them is a waste of time, bring along facts to back up your reasoning if required and you will be fine. I carried the NZ requirements for braided lines around with me on that bike for that reason.

NordieBoy

1st June 2008, 09:15

Bearing in mind bikes generally idle about 800-1100 rpm compared to a car which is much lower and only a couple of hundred rpm.

Stock idle on the DR650 is 1500rpm - Nice 'n thumpy through a SuperTrapp IDS with Race Core.

dino3310

1st June 2008, 10:02

great idea motu, looks good aswell

vagrant

2nd June 2008, 09:49

Great post, I was interested in the last comment though about how having a temporary silencer for warming up early in the morning so as not to wake up half the street.

It would also need to be put on/removed easily and quickly without burning your hands or scratching the chrome of the stock pipes.

Any ideas?

I had a length of old radiator hose attached to an old car muffler. The hose slipped over the bikes outlet stub. Easy to fit and remove, and kept the VFR to a nice quiet burble while warming up on the choke.
Then it was choke off, muffler off, and quietly idle off down the drive, before giving it the berries up the road:woohoo:

vagrant

2nd June 2008, 09:57

Well done.
Not wanting to put a downer on it but the WOF standards will now not allow adjustable mufflers. They are fine if the db killer, outlet etc is permanently attached - a rivet or weld is considered permanent a removable screw is not.

Is this applicable to designs such as Zorsts, http://sites.yellow.co.nz/site/motorcycleexhaustspecialists/ with the adjustable baffle plate inside, or just the removable plates that cover up the small rubbish bin that some people are using for a muffler these days.

Wired1

19th June 2008, 20:48

I was about to start a thread on just this subject so excellent timing. My SR400 rebuild took a nose dive today when it failed a re-cert WOF for lapsed rego. One of the two main failures was for "excessive noise exhaust". I'm running the supertrapp off my TT500 and although it was a temporary measure I like the look of it and would like to keep it on the bike.

So the photo's below, what I want to know is how to shut the fucker up just enough to keep the VTNZ happy. Looking at the other ideas around here I'm thinking of making a slip-on cover to go over the back end and a 45 degree down-bender at the end - what do you reckon?

Does removing the plates make it quieter? Should I repack it and with what? I've been told (by my boy-racer apprentice) that batts are a good filler!

Taz

19th June 2008, 21:03

Motu, Is the dry clutch on my ducati gonna push me over the limit? Gets quieter if you pull it in but will that be allowed?
Andy.

Can I come down some day and get the noise tested?

NordieBoy

19th June 2008, 21:17

Does removing the plates make it quieter? Should I repack it and with what? I've been told (by my boy-racer apprentice) that batts are a good filler!

Batts will work - for a while. Proper mat/fibre is cheap though.

Run it with 4 discs.
It'll be a lot quieter and have a bit more torque.

Once you've got your reg/wof then put the discs back in so you can reach the speed limit though.

sAsLEX

19th June 2008, 21:30

Is there any one in New Zealand who can test vehicles to the appropriate international standards for vehicle noise.......... or is it still the NZ hick test method Andy Cockerhead bought in a while back?

Wired1

19th June 2008, 21:33

Has anyone in Nelson got a Db meter? Is there an authorised DB measurer person here?

Wired1

20th June 2008, 18:54

NordieBoy

20th June 2008, 21:40

Go and see Gary at the Nelson Testing Station.
He's into Classic MX and ran a Supertrapp on his '79 XR500.
He may have some ideas.

Wired1

21st June 2008, 15:26

Supertrapp update: Pulled it apart today - it had 13 disks. Reduced it to 4 (thanks Nordie) and it is half the noise. It is such a difference I will just rock up to the VTNZ and see if they aggree without getting it measured.
I had a look at repacking it but I would need to drill out the pop rivets and it's not that old anyway, or not that used anyway, so I decided to give that a miss. It's quiet enough without it I reckon.

Motu

21st June 2008, 17:55

So I popped into VTNZ this arvo to ask them how they will assess my quietened supertapp and guess what - they don't have a Db meter! They use what they call "objective testing" which means it is just a matter of opinion. What a great system.

They don't have to have a Db meter,it's optional....and the subjective test is still in the way it's done.All they have to say is ''it's too loud''....and then you have to get an objective test done,and then have a piece of paper to say what it puts out.Don't get shitty with them,get shitty with the little turds in noisy cars annoying the public at wrong time wrong place - that is why we now have exhaust noise rules.

Wired1

21st June 2008, 18:12

Yeah I know, and to be fair my bike was pretty loud. At least it's quieter now.
The guys at VTNZ did mention getting it measured by someone in town but they said it might cost me ovewr $100 for the piece of paper - I think it would be fairer if the WOF guys had the tester in the first place.

Motu

21st June 2008, 19:19

I think it would be fairer if the WOF guys had the tester in the first place.

Geez,how many times do we have to explain this? Noise level can't be checked in a testing station or garage enviroment,it has to be a controlled enviroment,so the test is the same for you in Nelson,someone in rural Wairarapa or central Auckland.How fair would it be if I failed you at our facility right on SH1 and the Main Trunk Line,and then someone else passed it in some quiet rural setting.They'd be on here demanding name and shame.

Just make it quiet as.Is it a race core? Even at 4 discs my race core is bloody noisy....but still under 100Db.

Wired1

21st June 2008, 20:32

I bought it second hand so no idea. It is very quiet with four disk so probably not. I take your point re testing but my point is if they can't test it then they have no justification failing it - if they want to fail it then they need to test it not just say they think it's too loud - how loud is too loud? There needs to be a clear criteria. Imagine if traffice cops didn't bother measuring your speed just said "I think you were going too fast so here's a fine".

I also appreciate it puts the tester in an awkward situation having to buy a new instrument but exactly the same thing has happened to all the electricians in the country when the government said we have to buy a $1500 fault-loop impedance tester to be able to certify work we do - we don't have a choice we just have to either buy it or find another line of work.

Motu

22nd June 2008, 00:37

There IS clear criteria for noise - NO louder or LESS than the original system.The justification is that it's louder than stock,so that is a fail.If it fails you have to get an objective noise test.As for having to buy a meter - as I explained in the previous post,it's optional.The designated testing centers have the approved equipment.

geoffm

22nd June 2008, 07:26

A noise meter is $150 from Dick Smiths - don't tell me that mechanics are so poorly paid that they can't afford that.
IMO, if they are failing it, then they shoudl be measuring it to provide consistancy. As any background noise will increase the reading, then if it fails it is definitly to loud, or if the vehicle owner disagrees, then they can go and get a reading from a certified inspector with all the certified gear.
It is a typicla feelgood LTSA copout.

Wired1 - the cops do issue tickets without measuring the speed quite frequiently. No proof is required with a speeding ticket, as I can personally vouch for. A reason why a lot of people wouldn't go out of thei rway to help a traffic cop in trouble.

Wired1

22nd June 2008, 10:20

Yes I was thnking that was a bad example myself as I'm sure I've had one in my youth just for speeding without any specific speed mentioned.

Look I'm not trying to hijack this thread, and thanks for all the help I've had regarding my supertrapp, I'll take it back this week and see if they agree it's now "no noiseier than stock".