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SpankMe
30th June 2003, 11:08
I been hearing about bikers failing their WOF test because of exhaust noise levels, so it's time to start thinking about how to get around this new unnecessary law.

I was talking to Nukles the other day and he motioned a screw-in baffle that could be temporarily put in your exhaust. The screw expanded a ring in hold it in and the effect is a dead quiet exhaust and about 20hp loss in power. But since it is just for the ride to the WOF center, who cares.

So, does anyone know were such a device can be brought? I am going to be buying some flange-on Yoshimura’s soon and using this device would be easier than taking them off and putting the stock ones back on.

Also the new law does not stop you from modifying your exhaust, just making them lauder. So if the WOF guy hassles you about that thing sticking out of your exhaust, you can just say it was added to conform to the new law.

Motu
30th June 2003, 11:46
Nice try.

''The exhaust system and silencer must be so constructed or adapted that it's operation or effectiveness cannot be readily interfered with''

Coldkiwi
30th June 2003, 12:14
where's that written motu?

 

I've been having thoughts of simply unbolting the can and adding thin orifice plate between the can and exhaust piping.. very unobtrusive and I suspect would work quite well (once again, you get no power but who cares)

Motu
30th June 2003, 13:02
Outta the VIRM (vehicle inspection requirements manual) - the bible.

Hey,if it looks cool - it's cool.A piece of chicken wire held in with a roofing nail is not a good look,something that can't be seen or looks like it should be there in the first place won't be picked up by the average AVI who knows stuff all about bikes.

SpankMe
30th June 2003, 13:36
Well I guess I will have to keep my stock cans and just swap them over when I need to get a WOF.

750Y
30th June 2003, 13:41
perhaps unbolt the can, stuff some muffler packing in the pipe (or pink batts) get the wof, then unbolt and blow out and back on with the can/s.

Duke of Rogan
30th June 2003, 13:51
my bike has a stock can that has had its baffles removed, not sure how much HP it adds, but it is louder.
I wonder if it will fail when its time....

personally I think the idea behind this law is a good one, but what makes a good idea and good law is the way its enforced.

I'm sick of being woken up at 2-4am 'cos of some 1600cc car with an exchaust orrifice large enough to stuff a dead possum into.

Motu
30th June 2003, 15:57
Oh man ,it makes more noise,so it's got more horsepower - that's the kinda thinking that got us into this shit!

Duke of Rogan
1st July 2003, 11:45
thanks for that clarification Motu, but I am familiar the "free flow exhaust = increased HP" concept, just wasn't sure of how much increase one might expect to gain from removing the guts out of the stock can.

anyway, for a bit of a "noise" test yesterday, I re-installed two rubber "horns" (best name I can think for them) that are supposed to guide the air into the air-box under my tank as I had never rode with them on yet.
As a result, I discovered that probably 25% of the noise from my bike is from the air-box, as it was a lot quieter with the "horns" back in place, but there was a definate decrease in throttle response, so I promptly ripped them off again last night.
so when I take my bike for its WOF I will most likely re-install them again, just to make the bike appear a little quieter....

:done:

:beer:

Motu
1st July 2003, 13:27
I must admit to liking a bit of noise,and follow the more noise more power camp.I ride by ear and like to hear what is going on,a heavily muffled bike feels guttless to me,I have no idea where I am in the power band,looking at the tacho is not in the plan in the heat of the moment.

Induction noise is where more technology is being spent these days - as vehicle exhausts get quieter,induction noise gets more noticable.Compliance noise testing is done as a drive by,usually at full throttle,that's why production intakes are heavily restricted.

DZL
14th August 2003, 18:56
I've been pondering this very same thing recently, I reckon it wont be too hard to rig a length of perf thats a slip fit inside the can & have a closed inner pipe welded inside the perf to act as a baffle, & a simple expander that will tighten against the inside of the cans own perf to hold the thing in place for the WOF test.

 

This all reminds me of a pal who built a smallblock '57 Chev to run E Street-Modified class at the drags back around 1978. The only reg was that the vehicle MUST have a current WOF! His motor had EVERYTHING done & was dyno'd at over 500 HP, he actually won the Nationals with it first year out.

To get the WOF he stuffed the (gutted) 'mufflers' full of brass pot-scourers to shut her up, actually 'installed' the stuff just up the road from the testing station & rolled in quietly. Once he had the WOF sticker he hopped in to leave, wound her up, blew great wads of brass swarf back into the testing station as he layed rubber with a HUGE snakey off down the road.

Them wuz the daize!

;-))