Spark arrestor help for an MX guy.

It's been about 10 years since I last raced off-road, but I'd like to get back into it. I plan to enter the ULTRA GP at Strader Ranch in Oregon June 26th. I plan to race my 2002 YZ250, so I'll need a spark arrestor.

I've been looking at the Pro-Circuit SA / Silencer and the FMF Q-Stealth.

As per the race flyer, I need to pass a 99db maximum sound test.

I'm not worried about making my bike quiet for a race, just passing the sound check and having the USDA approved beef (er, I mean USFS spark arrestor).

Will the Pro Circuit spark arrestor pass a 99db sound check?

Will the FMF Q Stealth pass a sound check?

Which system is smaller?

Which system weighs less?

How much does each system change the jetting?

How much does each system change the power?

as far as sound testing goes both pipes should have no problem passing. i sound test alot of bikes at my work and 99.9% of all two strokes pass no problem no matter what pipe they have. the q stealth is very quiet but also bigger than the pc.

What we have noticed with FMF silencers;

- TurbineCore 2 SA (spark arrestor) around 94-98 dBa

http://shop.thumpertalk.com/catalogs/Tucker_Rocky_Offroad_2010/default.asp?p=17

- TurbineCore Q 92-96 dBa

http://shop.thumpertalk.com/catalogs/Tucker_Rocky_Offroad_2010/default.asp?p=14&s=2

- Q Stealth 88 to 94 dBa

http://shop.thumpertalk.com/catalogs/Tucker_Rocky_Offroad_2010/default.asp?p=15

I would bet a TC2 SA would be fine for your race. Anything more would be quieter, but also bigger & heavier. Coin toss.

We have never needed to mess with the jetting with any of these silencers, but we're not very fussy. :lol:

as far as sound testing goes both pipes should have no problem passing. i sound test alot of bikes at my work and 99.9% of all two strokes pass no problem no matter what pipe they have. the q stealth is very quiet but also bigger than the pc.
Spot on. :ride:

Thanks for your work in sound testing, motofreak. :lol:

I've ran with a Pro Circuit Nature Friendly and a Turbine Core II. I ditched the PC only because the mounts were cracking off, and several rewelds wouldn't stop it (I don't think the shop I took it really knew what they were doing on aluminum though).

After going back and forth a few times I notcied that the PC had more "bark" down low. It was throatier, had a bit better low end, and throttle response seemed sharper. Looking back at all my jetting notes the other day I realized that since running the FMF I've noted/complained about spooge with every setup, even when knowingly lean. Knowing what I know now, I'd pick a Nature Friendlt over a TCII any day.

Both silencers sound checked between 92-93 dB at various hare scrambles. I think twice I was in the 91.X dB range with the TurbineCore II.

leo vince is now selling a sweet 2-stroke silencer for the yz250. it is listed $169. it is spark arrested and it's supposed to be the quitest pipe out. looks awesome too. i am currently running the q stealth but i might try the leo just because i cant help myself. :ride:

here is the write up--

The Off-Road 2 Stroke Silencers of the LeoVince X3 range ensure the best quality, performance and price ratio for those who wish to customize their bikes simply, fast and with few modifications.

The silencer and the header pipe are totally made of TIG-welded stainless steel AISI 304.

The silencer is secured to the frame by means of carbon strips. The rear sump is made in carbon fibre.

The kit produced for the American market is complete with Spark Arrestor that has obtained USFS homologation from the United States Department of Agriculture – Forest Service. The Off-Road 2 Stroke Silencers respect the noise limits dB(A) required by the FIM.

.

Thanks for all the detailed info. I was leaning toward the PC but I wasn't sure about the sound test. I think I'll give one a try.

Adam728,

Every time I see a two stroke with a Q-Stealth, I see spooge. I never attributed it to the silencer, but the fact that a lot of trail riders just putt around and never change their stock jetting.

Rodgini,

Thanks for the suggestion on the Leo Vince.

I did a google search for each S/A on the YZ250 for a size comparison:

Leo Vince X3

echappement-moto-leovince-X3-YAMAHA-YZ-250_d9c038a8.jpg

FMF Q-Stealth

037.jpg

PC S/A

attachment.php?attachmentid=14919&stc=1

Thanks for all the detailed info. I was leaning toward the PC but I wasn't sure about the sound test. I think I'll give one a try.

Adam728,

Every time I see a two stroke with a Q-Stealth, I see spooge. I never attributed it to the silencer, but the fact that a lot of trail riders just putt around and never change their stock jetting.

Rodgini,

Thanks for the suggestion on the Leo Vince.

I did a google search for each S/A on the YZ250 for a size comparison:

Leo Vince X3

echappement-moto-leovince-X3-YAMAHA-YZ-250_d9c038a8.jpg

FMF Q-Stealth

037.jpg

PC S/A

attachment.php?attachmentid=14919&stc=1

no sweat. however, the middle pic is not a q stealth but rather just the q. here is a pic of q stealth. they look just like the fmf 4-stroke cans but they dont cost a dick & a nut.

P1030994.jpg

bikerack.jpg

bikerack.jpg

BEST BIKE STAND EVER! :lol: :lol: :ride::lol:

bikerack.jpg

BEST BIKE STAND EVER! :lol: :lol: :ride::lol:

:thumbsup:The soon to be patented bike parking log.

Q stealth...spooge? Mine has none, but I suppose it shows a propensity to catch some.

However, if you want full power, sa, and quiet, its the best. Actually, its in its own category with everyone bring up the rear with 10 year old technology. No idea on the leo as its brand new, but against everything else.

Rodgini,

I like the yellow "125". That would trick a lot of four stroke riders. Oh, and the bike parking logs look cool.

RCannon,

I still attribute the majority of spooge to riding style and terrain plus jetting. Do you really think the Q-Stealth is that far ahead? If it's that much quieter and maintains power, that's impressive.

My primary concerns are minimum size & weight, while getting past the tech inspection.

Rodgini,

I like the yellow "125". That would trick a lot of four stroke riders. Oh, and the bike parking logs look cool.

RCannon,

I still attribute the majority of spooge to riding style and terrain plus jetting. Do you really think the Q-Stealth is that far ahead? If it's that much quieter and maintains power, that's impressive.

My primary concerns are minimum size & weight, while getting past the tech inspection.

It is that far ahead. Quiet is easy, spark arrestor si easy. But combining both with incredible power is not. FMF did it. I think others could as well, but so far...

size and weight, no way..its a big silencer. Weight is not bad, though. Not that heavy, just big.

It is that far ahead. Quiet is easy, spark arrestor si easy. But combining both with incredible power is not. FMF did it. I think others could as well, but so far...

size and weight, no way..its a big silencer. Weight is not bad, though. Not that heavy, just big.

Any Idea how the Q-Stealth stacks up to the turbin core two powerwise? I have been eying the QS for awhile but I talked myself out of it if it because i didn't think I would make any gains from it, plus I just completely rebuilt my TC2. But if it truely betters the TC2 then I want one, the upgraded looks are undeniable.

Will the Pro Circuit spark arrestor pass a 99db sound check? Yes

Will the FMF Q Stealth pass a sound check? Yes

Which system is smaller? PC

Which system weighs less? Probably PC

How much does each system change the jetting? don't know

How much does each system change the power? The pc did not affect the power on my 06 yz 250 and worked awesome with the pc platinum 2 - the stealth did not change power at least noticably on my 250 xc.

...I still attribute the majority of spooge to riding style and terrain plus jetting.
Agree here. I bet 125s spooge less simply because they are ridden closer to their full potential, whereas many 250s are ridden lower down in the revs -- at least on the trail.
Do you really think the Q-Stealth is that far ahead? If it's that much quieter and maintains power, that's impressive.
The Q Stealth is a big step forward. It's quieter than the standard Q, yet weighs less. It is large though, but nothing you'll notice while riding.

Out of all the silencers we've run, I've never noticed a power difference; 2-strokes are kind of blessed that way. :lol:

The Stealth certainly doesn't restrict our bikes; they're still stupid fast.

My primary concerns are minimum size & weight, while getting past the tech inspection.
Any silencer with a spark arrestor will get you through a 99dBa sound check. Only the 4-strokes need to worry about that one. :lol:

But if sound limits are ever lowered in the future, you'll be needing more silencing than a TC2.

I can't speak to the PC, but a Stealth probably weighs the same as a TC2...

Get a Q Stealth and trim about 3 inches off the length! :ride::lol:

But if sound limits are ever lowered in the future, you'll be needing more silencing than a TC2.

I can't speak to the PC, but a Stealth probably weighs the same as a TC2...

Get a Q Stealth and trim about 3 inches off the length! :ride::lol:

While I'm all for quiet, I'm not sure you'll need more than a tc2 for sound tests. In az 96 dB was the limit, I never checked over 93.x. Several other us guys were in the range of 91-94 dB with "non-quiet" silencers.

I recall my pc feeling lighter than my tc2, not that you could tell on the bike.

I do agree trail riding and low cylinder/exhaust temps contribute to spooge. Fast, open stuff I can rock without spooge. But with the pc I was spooge free everywhere.

While I'm all for quiet, I'm not sure you'll need more than a tc2 for sound tests. In az 96 dB was the limit, I never checked over 93.x. Several other us guys were in the range of 91-94 dB with "non-quiet" silencers.
Yeah, I guess I should have said, "In my experience..." :lol:

While I’m sure the TC2 can be quiet enough for most situations, we could barely get our TC2s through 94dBa sound checks at our events; we would have to ride around to warm things up, keep the clutch pulled in, and hold a boot against the pipe!

Perhaps there is a difference in testing procedures. :ride:

We eventually moved to the Q just to avoid the uncertainty.

:thumbsup:The soon to be patented bike parking log.

thanks guys. it's a bavarian design....very practical.

Rodgini,

I like the yellow "125". That would trick a lot of four stroke riders. Oh, and the bike parking logs look cool.

RCannon,

I still attribute the majority of spooge to riding style and terrain plus jetting. Do you really think the Q-Stealth is that far ahead? If it's that much quieter and maintains power, that's impressive.

My primary concerns are minimum size & weight, while getting past the tech inspection.

i only get spooge with my stealth when i ride the tightest of the tight single track. i imagine i could jet for these conditions but i have my bike jetted for all around riding.

yeah the 125 is gone now but it was pretty funny especially since it's a 295!!!

I've got a YZ 295 and the tube snapped inside the silencer today while riding. Needless to say afterwards the packing blew into the tube and I had about as much power as an Xr70 on the 3 mile ride back to the truck.

I was running a pro cirucuit platinum, stock silencer. I need something in a hurry. I do need a SA in a few months so this might be a good time to get something with one.

How about the pc nature friendly vs pc304 factory sound. I'd probably go with a Q stealth but it doesn't look like they make it for a 99. This is my desert bike now. I have a pc 304 factory sound on my newer track bike and am very happy with it. Seems to rev a bit better than stock. Looks like they make the turbine core 2 for a 99 as well.

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