How can I make my bike quieter?

[gtsnowcrack]

I have a 2004 EC200 with a Gnarly pipe and stock silencer (FMF Turbine Core something or other) It has the LTR PV cover and LTR jetting kit. I race and noise is a problem for me. Even with a repacked silencer I blow 96+ dB. Listening to the bike it seems like most of the noise is coming from the front of the bike but the pipe is seated well on the cylinder. Anyone have any experience/suggestions?

[jeffd]

A couple of things...

1. A skid plate reflects noise and increases db reading.

2. A carbon fiber pipe guard dampens noise from pipe and reduces db reading.

3. Silent sport packing helps a tad. This looks like stringy cotton versus the fiberglass matting that comes in the silencer stock. What did you use when you re-packed it last?

4. The db snorkel looks interesting. Have you checked it out? www.thedbsnorkel.com

5. The oem silencer that comes on euro models is noticably quieter - it meets ISDE spec of 94 dB. Unfortunately it lacks a spark arrestor. Erik Kangas recently took delivery of his '06 and had to add a spark arrestor - it was a Cobra Sparky spark arrestor made to fit an FMF silencer for a CR250. The part number is 9157. A few bikes have been recently delivered into the U.S. with this silencer - it probably wouldn't be hard to find a "take off".

-----

I might have a euro silencer in my garage - are you interested in it? I'll take a look tonite.

- jeff

[gtsnowcrack]

1. Skid plate, I was thinking about some some foam and weatherstripping to damp the noise.

2. Might have to go pick up a CF pipe guard. Also I think I was told that the pipes on the european GG's were double walled? And were quieter?

3. I'm pretty sure the packing was the sheet not the stringy stuff.

4. Seen the dB Snorkel, there's a couple guys around here that have one... Actually dropped one guys CR500 a good 8 db to pass sound for a race. I'm just not sure if it will help because most of the sound is coming from the front of the bike not the back. I'll see if I can borrow one and test the sound difference.

5. Definitely be interested in trying a Euro silencer, but again, I'm not sure if that's where the problem was.

It's just so irritating! I know so many people with KTM's and their bikes are in the 80's sound wise and I feel like a complete jerk with my loud bike.

[MattR]

Just curious... I've seen the header wrap tape used on 4T bikes to get a better internal chamber temperature (and less accidental burns to yourself). Could this be used on the 2T bikes to provide some sound absorption?

It would also serve to maintain pipe temperatures which in-turn influence internal pressure. Of course, the 2T pipe shape does not lend itself to easily wrap it with tape. I've been curious about the idea for a while. The cost of the tape is holding me back from trying it (about $50).

Here is some from Helix to give you an idea (50in x 1in). There is also a 2in width.

[Brian VT]

Originally Posted by gtsnowcrack

I know so many people with KTM's and their bikes are in the 80's sound wise and I feel like a complete jerk with my loud bike.

+2. The KTMs are quiet. I'd love to get my EC down in that db range. I won't give up my Gasser though. I love it more every time I ride it and it has squeaked by the sound checks so far.

[gtsnowcrack]

I actually have a pack of exhaust wrap from DEI that I was going to use at the last race for just incase I didn't pass. It's a 2"X50" roll. I haven't put it on yet because my pipe needed some dents removed.

I'll give a report once I put it on and see if I can borrow a sound meter.

Originally Posted by MattR

Just curious... I've seen the header wrap tape used on 4T bikes to get a better internal chamber temperature (and less accidental burns to yourself). Could this be used on the 2T bikes to provide some sound absorption?

It would also serve to maintain pipe temperatures which in-turn influence internal pressure. Of course, the 2T pipe shape does not lend itself to easily wrap it with tape. I've been curious about the idea for a while. The cost of the tape is holding me back from trying it (about $50).

Here is some from Helix to give you an idea (50in x 1in). There is also a 2in width.

[Cruiser]

Be careful with the pipe wrap! It works but it will kill the pipe. It keeps heat in and makes the thin pipes brittle and they are prone to blow out type failures. I've seen this on drag cars and have heard its worse with the thin 2stroke pipes. You could try getting it ceramic coated. Also I have a dbsnorkel and it works well, just looks goofy. Use the foam under the skid plate and modify a ktm stock silencer to fit your bike. It will be quieter. I have a PC ISDE silencer on my 97 and its a deeper sound. I had to modify it so it aint perty but its on.
Good luck,,
Steve C

[Magellan]

Originally Posted by jeffd

5. The oem silencer that comes on euro models is noticably quieter - it meets ISDE spec of 94 dB. Unfortunately it lacks a spark arrestor. Erik Kangas recently took delivery of his '06 and had to add a spark arrestor - it was a Cobra Sparky spark arrestor made to fit an FMF silencer for a CR250. The part number is 9157. A few bikes have been recently delivered into the U.S. with this silencer - it probably wouldn't be hard to find a "take off".

My 04 EC300 regular gets a 91 or 92 dB when I go racing. I have yet to repack it.

[WoodsRider]

Back in February, at the Snowrun Enduro, my '01 XC300 tested at 99 decibels, with the stock FMF pipe and stock FMF TC2 silencer. After that I repacked the silencer and installed a Motowest pipe with an E-line CF guard. In April my club did some sound tests to get read for our hare scramble (NETRA requires sound testing at all events) and my bike measured 93 and 94 decibels.

In May I installed a dbsnorkel. When I first cranked it up I wasn't very impressed with the sound reduction. Then I isolated the engine noise from the exhaust and could definitely tell a difference in tone with the dbsnorkel installed.

There's quite a bit of engine noise reflected off the skid plate and I don't like using foam. Tried insulating it with some garden hose, but was afraid this would allow the skid plate to move around so I removed the hose. At the last two enduros, Somers Fun Fun Fun and Little Rhody, it tested 87 and 88 decibels respectively.

[MattR]

Originally Posted by WoodsRider

At the last two enduros, Somers Fun Fun Fun and Little Rhody, it tested 87 and 88 decibels respectively.

Were these low numbers due to the dBSnorkel or the garden hose/foam isolation on the skid plate?