Warning re exhaust systems.

[AllanB]

That's a bit naff. Why not set at a % of the max revs?

For example my Hornet has a pretty tame red-line of 9500 so 4500 rpm is just under 50%, A GSXZXRYZ thingy revving to what 13500? or higher possibly would be on only 30% of max thus resulting in a unfair comparison.

I feel a need to cry discrimination especially since my bike is black....

[rat biker 08]

Yes i agree but how are thay going to test my bike its 30 years old and l have a four into one pipe at 4500 rpm its loud . Dose that mean i have to put the proper pipes back on if i can get them.

[RDJ]

Use to amaze me how that dude toured all over the place and his only 'equipment' was a rolled-up Mexican blanket strapped to the handle-bar!!

(But use to dream of one day having a bike like that - without the blanket!!)

Didn't the blonde girl drive his Long Way Round-type support vehicle? And yeah, the bike was definitely worth wanting.

[peasea]

I just saw the latest missive from LTSA.
It seems that in 6 months time all vehicles origonally fitted with catylitic converters in their vehicles will be reqired to have them fitted in order to pass a WOF.
Clearly aimed at the boy racer set with their drainpipe exhausts this could have a nasty effect on us bikers.

Don't fret, unless you want to trade your bike for a boy racer-mobile or have a passion for really pissing people off. (Same thing I suppose.) The average WOF tester (with all due respect) won't know the difference and will go by his/her ear.

As you were.

[FROSTY:Me]

Depends what you call "average"

[MIXONE]

I had the cat removed from my car a little while back.The difference in sound is negligible however I get better economy and the turbo spools up much faster.

[peasea]

Depends what you call "average"

Yeah, they can be a bit picky and some days they seem to have mood swings. I had a drama a while back over mufflers and I'd been going to the same place with the same mufflers for four years. Twat bumped me, I did the old muffler switch, I then got the WOF and they lost a longtime customer. (In fact, several.)

[McJim]

2 stroke single................6,000rpm
2 stroke multi.................5,000
4 stroke single................3,000
4 stroke 2 valve twin.......2,500
4 stroke 3 valve+ twin.....4,000
4 stroke 3 cyl +..............4,500
Rotary..........................4,500
more than 5 cyl..............4,000
more than 5 cyl dohc vvt.4,800
6 cyl............................3,200
8 cyl............................3,000
more than 8 cyl..............4,000
Diesel...........................2,500

However any arrogant sods who think they know best will have the snot revved out of their bike just to see the colour drain from their face.....

I'll take that one please. My bike doesn't make much noise at that 2500rpm but she do sing purdy around 7,000....

[El Dopa]

So the answer (as it usually is) is to find a wof tester who is bike friendly.

[alanzs]

What's loud? I can't HEAR YOU? my bikes on...

[El Dopa]

Went and had a talk to the guy who normally does my WOF today - he's had a quick initial look at the regs and already has a headache.

He didn't really have much useful detailed info to add, but he did say that he thought a gsxr750 straight off the showroom floor would probably fail, so it's going to be interesting to see how this shakes down....

[Ixion]

Revs that the test is done at is 50% of peak power revs if known; if not known the figues Mr Motu posted.

From here

Motorcycle engines 2.6(2)
The engine speed for the exhaust noise emission test of a motorcycle engine, must, for the duration of each test, be within a tolerance of +/- 5% of either:
(a) in the case of an engine that has a manufacturer’s engine speed maximum power (ESMP) that is known to the LVV certifier, 50% of that figure; or

(b) in the case of an engine that does not have a manufacturer’s ESMP that is known to the LVV certifier, or the manufacturer’s ESMP has become irrelevant because the engine is now outside of its original specification:
(i) 6000 RPM if the engine is a 2-stroke single-cylinder engine; or
(ii) 5000 RPM if the engine is a 2-stroke multi-cylinder engine; or
(iii) 3000 RPM if the engine is a 4-stroke single-cylinder engine; or
(iv) 2500 RPM if the engine is a 4-stroke twin-cylinder engine with 2 valves per cylinder; or
(v) 4000 RPM if the engine is a 4-stroke twin-cylinder engine with 3 or more valves per cylinder; or
(vi) 4500 RPM if the engine is a 4-stroke engine that has three or more cylinders; or
(c) in the case where a low volume vehicle certifier believes the engine speeds specified in 2.6(2)(b) are unreasonably high, taking into account the type and age of the engine, he may apply an engine speed for the purpose of the sound level test at which he believes is appropriate for the engine, and at which the engine

Worth bearing in mind if you have a low revving two smoker and someone wants to test it at 6000rpm.Some of mine would blow up at those revs.

Dunno what weird logic whoever came up with those figures was using. I mean, why on earth would a single be higher revving than a twin?

I'm trying to follow up on the issue of "standard zorst in good nick, just like it left the fcatory, but still more than 100db" with LTSA. As I read the law it applies only to MODIFIED or DEFECTIVE .

[Motu]

I think so long as it looks standard,it'll be taken as that so long as it's not too loud.If the system is after market and quiet,all is good....but if it's loud then look out.Time to remove those labels.

This is assuming AVI's of Kiwi extraction....if you go to a testing station where the AVI's are of Indian origin then it's almost certain you will fail,no matter what.

[Ixion]

Many OEM silencers have the makers name stamped on them (Suzuki, Yamaha etc) If so, pointing it out to a problematic tester could be useful. "See, it's the original Suzuki silencer. And you can see it's in good condition"

[Motu]

That's why my original muffler with all the numbers and Yamaha name and unmolested is a treasured possession....although I am a rule unto myself.

Of course the rule is aimed at cars,and it's pretty easy to pick up unoriginal.I think I'll be looking at well constructed systems,with a couple of hot dogs and reasonable sized muffler as ok.Resonators and cats cut out with a huge straight through can will be out.Cooper S and other OE style mufflers are good to me,same as those flowmaster's and the like - they all make a good attempt at noise reduction and look the real deal.

Supertrapp and others of the same construction are a well engineered and scientifically constructed system....I would consider them as a good system above some generic straight through perforated pipe with pink bats packing and a stainless or carbon outer.I think the intent of the system will be a deciding factor - is this to make more noise or to enhance performance?