South West Bikers | Motorcycle Forum

I notice that when you guys talk of various track days you give a dB limit and I know the reason behind this.

At Castle Combe recently they had me rev my engine to 9750 rpm and it registered 103dB.

Having seen some of the limits mentioned of 101dB, I find it hard to believe that a new unmodified (small engined) bike would exceed that limit.

Do you think the Castle Combe measurement was wrong?

Castle Combe measure different to most tracks. I'm sure someone will confirm exactly where they measure from but most other tracks that state limits of 98/102/105dB are measured from a fair distance from the exhaust at an angle too, plus a lower RPM. 7500rpm for 600, 5500rpm for 1000 IL4 from memory.

My R1 with stock cans measures below 90dB.

If I recall correctly Castle Coombe had stock GSXR600's and R6's failing their noise test when the low level "stubby" style cans were introduced on those models. One reason why it's not a very popular trackday location ........

they test at 3/4 max revs from a distance of 1m. many new bikes with standard cans don't pass.

Did they test all those rozzer bikes ??

So it's dependent on how far from the exhaust they monitor it ?

Do you people get noise level checks before going to the track then? - I don't fancy the expense of travel, accommodation & track to find out the bikes won't be allowed.

Atomic wrote:
Do you people get noise level checks before going to the track then? - I don't fancy the expense of travel, accommodation & track to find out the bikes won't be allowed.

Noisy day at Donington it is then

I failed miserably at Castle Combe - 107db
No probs where it's been 'normal' testing and a 102db limit (yet)

jer r1 wrote:they test at 3/4 max revs from a distance of 1m.

think it was half a meter last time i was there, failed 108db and 109db with ebay baffles

shammy666 wrote: No probs where it's been 'normal' testing and a 102db limit (yet)

so i could keep my cans on for llandow then??

shammy666 wrote: Noisy day at Donington it is then

I failed miserably at Castle Combe - 107db
No probs where it's been 'normal' testing and a 102db limit (yet)

Haha, I think not. I have the safety day at Castle Combe in a couple of weeks and then LLandow in June for my first track day. Who knows from there, it could be the start of a new hobby ( although a very slow one!).
I will check my local garage tomorrow to see if they have a dB reader.

You won't have any issues with Llandow - not sure if they even know what a dB meter is

I find moving the rev counter needle helps. Not had a problem since.....

Just for a bit of clarification guys, below is a table that shows what rpm you will be asked to use when the being tested at most tracks excl Castle Combe.
For example a 600 4cly machine will be asked to use 7000rpm at most tracks.
At Castle Combe you are asked to use 3/4 max revs which on an R6 is 11/12000 rpm, this is why most fail.

Want a tip? Pop down to CC on a TD and they will happily sound test it for you so you know what level you are at.

Struggling to get under the limit?
Use a baffle and if a baffle isn't enough, lockwire a stainless steel scourer to the baffle. I used this technique at my last CC trackday and it worked a treat!

J3Math wrote:Just for a bit of clarification guys, below is a table that shows what rpm you will be asked to use when the being tested at most tracks excl Castle Combe.
For example a 600 4cly machine will be asked to use 7000rpm at most tracks.
At Castle Combe you are asked to use 3/4 max revs which on an R6 is 11/12000 rpm, this is why most fail.

Want a tip? Pop down to CC on a TD and they will happily sound test it for you so you know what level you are at.

Struggling to get under the limit?
Use a baffle and if a baffle isn't enough, lockwire a stainless steel scourer to the baffle. I used this technique at my last CC trackday and it worked a treat!

great stuff for some ....... but you can't put any additional baffle's in my MV's pipes (no way of fixing them in), and to be honest, short of blocking one or two of the pipes I can't see it ever meeting requirements revving at 9500rpm

Even with baffles in I reckon it's doubtfull the TL would be that quiet at 8650rpm .....

Might be fun to turn up for a mass noise test though ......... how standard machines can fail, even though they can legally be ridden around the local roads, is beyond me ....

Simple buy a rev meter that can be adjusted! I know they exist!

Cheers for the advice all.
Went to my local chap who didn't have a dB meter so went to Honda dealer for their opinion on the newish Hornet that is apparently loud!
Their MOT testers go by hearing and sight.
If it sounds loud then they will issue a warning.
If the exhaust is stamped 'not road legal' they will fail it. However if the stamp is covered by a bit of tape for example, it will pass because they are not allowed to remove the covering.

He also said the same as you chaps - CC is the worst for not allowing bikes due to their methods, I.E. as you said too high revs etc. etc.