Yamaha TRX850 Enthusiasts Forum

Ok, I'm fed up with having to swap my whole exhaust system (cans and headers plus taking the bellypan off and putting back on the pillion peg hangers etc) every spring for the old MOT test.

Also, I want to do more trackdays at Donington and most are 'quiet' days limited to 98db. I know my system is loud cos it was noise tested at Cadwell last year and came in at about 105db. So......

...do decibel killer inserts/baffles work?

...anyone got any for sale?

...anyone know where I can get some?


Ta,

Dave.

P.S. Don't try and tell me about 'friendly' MOT stations cos in the real world, these don't exist! ...and my cans are LOUD!!

IIRC you've got Scorpions? I've got the baffles from my Scorpions that you could borrow (if they'll fit). They got mine through the MOT - but sadly fell out shortly after (actually true - one of them did!!)




PS - they do ... and so are mine

trixynut wrote:Ok, I'm fed up with having to swap my whole exhaust system (cans and headers plus taking the bellypan off and putting back on the pillion peg hangers etc) every spring for the old MOT test.

Also, I want to do more trackdays at Donington and most are 'quiet' days limited to 98db. I know my system is loud cos it was noise tested at Cadwell last year and came in at about 105db. So......

...do decibel killer inserts/baffles work?

...anyone got any for sale?

...anyone know where I can get some?


Ta,

Dave.

P.S. Don't try and tell me about 'friendly' MOT stations cos in the real world, these don't exist! ...and my cans are LOUD!!

A while back i followed a duscussion regarding dB killer and the general opinion was that they work but poor! Some dude had measured a 3dB decrease....that´s not much when your at 105!

If you put in restrictors for silent trackday and get them approved i would guess the bike won´t run as you are used to.

There are a bloke on evilbay who´s welding up cheap ones, and you have the standard 2" viper ones.....if you want to have a go at it.

Ebay example

IIRC you've got Scorpions? I've got the baffles from my Scorpions that you could borrow (if they'll fit)

...I got an unknown system, most likely Renegade.

....thanks for the offer, but by the time I've paid postage both ways to get them off you for a couple of MOT's I may as well have bought some .... if they work?!? .... otherwise I'd have to pay, like, a million quid in petrol to pick them up/drop them back to you down in Clottedcreamland! Maybe.

Given me another thought though Jak .......

....any of you helpful local-to Leicester-or-Milton Keynes guys got a set I could borrow for about a week in the spring?

trixynut wrote:Clottedcreamland!

If you get stuck just shout - I can always bring them to Avebury in March and I think I'm heading to Yorkshire in April (although I'm guessing your MOT is sooner than that or you wouldn't be asking now!).

If you need any measurements/photos (of the baffles!!!) just shout and I'll dig them out for you.

If you need any measurements/photos (of the baffles!!!) just shout and I'll dig them out for you

Get ya baffles out!!

Thanks for the kind offer, I'll see how it goes.

If you put in restrictors for silent trackday and get them approved i would guess the bike won´t run as you are used to.

True, but I've done one with the standard cans but still with the FCR's and it performed ...... ok.

Trix..

You could try re-packing your cans...

I compared my Akra to Martins at Avebury and was surprised at how quiet his was compared to mine. His was soft but nicely 'boomy' where mine had a real harsh blatty quality to it. All became clear when I took the can apart and found no more than a few flakes or carbonised glass fibre! I ended up going to the local bike shop (run by twats I will add) who sold me some g/f matting for about £12. he promised it would fluff up when I put it in the can, but it didn't and I ended up stuffing simple old loft insulation into the gaps on top of the sh!te matting. When I started it up all the harshness it had before was gone and I got a nice soft boomy noise again. I don't have a dB meter, but it is quieter than it was before and oddly gets quieter when it's hot too....


G

http://www.performanceracingparts.co.uk ... asp?cat=21

These guys sell them along with other exhaust components and wadding.

They're in Louth, Lincs.

trixynut wrote:Get ya baffles out!!

was gonna change it but couldn't think how to reword it so there was no double-meaning

Off topic ... but ...
Greg - LMAO at your avatar - did Mrs Greg get hold of the camera/pc

Hardy har ...

Seeing as I'm having more than my fair share of Moroccan moments just now, I thought I'd change the pic... that one was taken inside a little cafe (scroll to 4th pic) in a place called Agoudal on the road from Imilchil . We'd just ridden about 150km on dirt track and I was suffering from the most horrendous bout of the sh!ts I have ever experienced. I was completely knackered having been awake most of the previous night "with all vents open" so to speak. All I could keep down was flat Coke (top tip for any other gastric upset sufferers out there ) and we still had another 90k to go. That day I was not impressed..!

G

Killerwhale wrote:
A while back i followed a duscussion regarding dB killer and the general opinion was that they work but poor! Some dude had measured a 3dB decrease....that´s not much when your at 105!

If you put in restrictors for silent trackday and get them approved i would guess the bike won´t run as you are used to.

3dB is a pretty good job really, it's a halving of power. It's just 105 dB is high to start with.

As for the running, I tested my Tuono on the Dyno with and without the baffle and it made bugger all difference throughout the whole curve, other than at the very top when it made around 7BHp difference, which you don't miss on that bike anyway.

I've run my TRX with and without baffles in place and i can't tell the difference, other than the subdued noise.

as stated, repack your cans with different material. It wont effect your power, it just effects your reverberation thru the can.
If you can be bothered, you can also find a small drill bit, that is a bit larger than your holes in the tube with bazillions of holes in it, drill out every 2nd hole to that larger size.

This allows more air pressure to push thru the holes and be absorbed by the matting. ive heard (altho not tested this one) that if you "bend" each of the new holes you drilled out, so it acts like a scoop, meaning, pull the drillbit towards the BACK of the exhaust once is in the hole, it should bend to "ramp" the air into the padding.

See the pic of the baffle that KW linked. See how they are ramp / scoop shaped ?
I dont know how this will effect your power. I suspect it wouldnt be much, but i suspect it will effect your flow some how, but it would be VERY small.

Hope this helps.

OH !! lastly, ive also heard (yet again not tested) that if you get some really high temp rubber matting, some soft rubber, not rock hard, you put layer inside your exhaust touching the outter metal..
get the centre bit with holes, put some packing sound deadner material around it, wrap it up in the rubber like a hotdog, slide it into the exhaust so its tight in there. Ive heard this helps with heat + sound + vibration.. I have no idea if its true tho as im yet to meet someone who has actually done it.. But that rubber matting would be hell expensive to be high temp enough.