Spark arrestor

13 replies to this topic
  • Squidwerd_on_a_400f

Posted October 22, 2001 - 02:11 PM


I wish to ride a h/s and am currently running a FMF powercore 4 un spark arrested? Is there anyway to make my own s/a or do I have to put out the money? First h/s for me. I have the stock pipe also, which is not s/a either. Any ideas would be greatly appreciated. ECEA organized H/S.

  • Thumpologist

Posted October 22, 2001 - 04:35 PM


Take a ky-way sparky cobra spark arrester,weld on an aluminum flange that will flare out to to the outside of a stock exhaust and overlap it by about 3/8", cut a notch in the bottom to allow it to tighten then use a stainless steel hose clamp to keep it on. Works great, is legal and you can remove in a heartbeat for the track.

  • skthom

Posted October 22, 2001 - 04:42 PM


Do a search on spark arrestor. Someone else on the forum drilled out the rivets on the endcap, installed a 1/4" mesh screen and put the endcap back on. Otherwise you can try a spark arrestor endcap from Bills motorcycles in Oregon for about $130. Do a search on BMP to find out more...

Good luck.

  • skthom

Posted October 22, 2001 - 04:44 PM


Sorry. Forgot to mention that I was talking about the stock silencer...

  • Mr_Toyz

Posted October 23, 2001 - 06:02 AM


That guy was me. You can drill out the rivets and sandwich in a screen. I got my screen from BBR (they're local). I would advise looking for and actual spark arrestor screen if you can. It can be tricky pushing the cap back on after you've go the screen in there, just use some mussle.

Please keep in mind this is not totally legal. YZ silencers still have still have the "closed course" waring on them. (the 01's sand off nicely Posted Image) A legal spark arrested silencer also requires a forestry approved stamp. But hey not everyone can be perfect! Posted Image

Good Luck!

Mr T

  • bbeakley

Posted October 23, 2001 - 07:32 AM


I've written FMF regarding the same question and haven't heard back from them yet. Looking at the S/A version of the powercore IV, it looks like you could drill out the rivets on your current silencer, remove it, then rivet the S/A end cap on. The end cap has all the forestry B.S. on it so it should make it legal (no stamping to the contrary on the main body of the silencer). Trick is finding a S/A end cap. I'm hoping FMF will sell them, but I didn't see it on their web site and still haven't heard from them. *Sigh*, maybe I'll go to my local FMF dealer and ask.

  • BikeDestroyer

Posted October 23, 2001 - 09:35 PM


FMF does sell the S/A endcap. They sell the MX Full Flow endcap $40.00. The S/A endcap is $30.00. And the Quiet Core endcap is $50.00. or 310-631-4363

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  • bbeakley

Posted October 23, 2001 - 10:31 AM


Did you actually find reference to those parts on their web site (or did you call them)? I looked, but maybe the LASIK isn't working too well for me. Please tell me where to look so I can get the S/A end cap ordered. Thx -Brian

  • canavero

Posted October 23, 2001 - 01:11 PM


In response to the FMF end cap removed and riveted or srewed to the stock silencer.

I tried taking a FMF PWR CORE 4 and putting it on my stock silencer - it did not work. They are just slightly off and will not fit. A great idea but...

let me know if someone else has made it work.

  • Squidwerd_on_a_400f

Posted October 23, 2001 - 01:59 PM


just got off the phone w/ fmf and they no longer make the s/a for the powercore 4 in the oval core type only the newer square type core. I hate Murphys law!

  • Squidwerd_on_a_400f

Posted October 23, 2001 - 02:00 PM


Sorry, that is the end caps I'm referring too.

  • fershy

Posted October 24, 2001 - 04:54 AM


Squidy, I would get a hold of some stainless steel screen install it in your existing end cone yourself. Use a ball peen to curve the screen as like the FMF SA. This increases the surface area. Then have it brazed in place. Nice to cut those clowns over at FMF out of a little revenue. As you found out, they are not keen to support their now "antiquated" systems. What are they on now the Powercore 7 super stealth?

[This message has been edited by fershy (edited October 24, 2001).]

  • marty_mosley

Posted October 27, 2001 - 11:04 AM


where can I buy some fo that stainless steel screen at?


  • dirtdad

Posted October 30, 2001 - 09:04 AM


Great looking item. Where was it 10 months ago when I needed it!!!! :)

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