FMF Q4 Mod tested

Somewhere on the web I bumped into a great idea to modify the Q4 spark arrestor to reduce the sound.
So I bought an extra spark arrestor for $35 and tried it out.
The idea is that you cut some slots in the end of the arrestor and bend the tabs over the block the pipe a bit. I used duct tape to mark where I was going to cut:

Here are a few shots of the modified spark arrestor next to an unmodified one:

Results:

FMF Q4 with Spark Arrestor

RPM            Original          Modified

2000             87 dB                87 dB

6000             102 dB               102 dB (whistle sound noticed on modified)

8000             106 dB               106 dB

No improvement! Wow, I really expected this to work.  I guess I could bend the tabs down some more, but I don't want to crudely block the exhaust too much. I guess the lesson is that you need actual baffling, not just some blockage.

Another note is that these measurements with the original spark arrestor are different from the ones in my last post a couple days back. Just shows how variable this testing is.

FMF Q4 Muffler (slip on) vs the stock Arrow muffler on a Husqvarna TE250

I decided to try a FMF Q3 Muffler (#045338) on my 2010 Husqvarna TE250. The FMF Q4 is an aluminum muffler for which they claim a maximum of 96 dB. This information probably applies to the other 4 stroke Huskys with an Arrow exhaust for 2011 and 2012 too, like the TE310.

From the dealer, my Husky was pretty quiet, but it had the catalytic converter and the throttle stop then. If you follow the power up directions your remove both of those. And then the bike is really loud, with just the stock spark arrestor. But the power up directions also tell you to take the spark arrestor out and to put the baffle that comes in the kit in the pipe. This does make the bike a bit quieter.

So then you have a problem, if you like a quiet bike. First, with the stock kit baffle the bike still is pretty loud. Second, if you use the baffle, you don't have a spark arrestor.

“danbartol” on cafehusky did a bunch of research and testing on this. His comments are here:

http://www.cafehusky.com/threads/exhaust-db-comparison.8623/

Here are the stock Husky baffle options:

On the far right is the spark arrestor that comes with the bike. The middle baffle comes in the power up kit, and does quiet the bike down, but has no spark arrestor. (The baffle on the far left is a part you can buy from husky. It does quiet the bike down very nicely, but is very restrictive and still has no spark arrestor.)

I ended up welding a mesh screen on the end of the middle baffle (like Dan did), the one that came in the power up kit, and I've been running that. Here is a shot with the screen:

 But lately I've been going to some forests and have been concerned that the cobby mesh wouldn't pass muster. And I was hopeful that a Q4 from FMF might be quieter. And I also really like reducing my bikes weight, and the Q4 was likely lighter than the stock muffler.

The Q4 looks nicely blocked up inside, it's not a straight thru pipe:

Additionally, it comes with a spark arrestor that bolts in the end:

Weight comparison:

Stock Husqvarna with baffle: 113 oz (3204g) (baffle with tacked on screen weighs 5.2 oz or 156g)

FMF Q4: 91 oz (2576g) (Note FMF claims 6.1 pounds or 97.6 oz, maybe they count the hardware or something)

So the FMF is about 1.38 pounds lighter! That's cool.

Sound test:

Here was my setup. I roughly followed the AMA standard, by attempting to put the meter 20 inches at a 45 degree angle from the pipe. But my meter is a cheapo and this is not the right environment to test. All I was hoping to do was compare the two pipes. Note these tests are very rough, with me just trying to get the rpm right and then taking a quick look at the dB meter.

Stock pipe:

Q4:

Results:

Stock with baffle and custom on spark arrestor. Cat converter removed.

RPM            A weight           C weight

2000             88 dB                95 dB

6000             98 dB                103 dB

8000             104 dB               no test

FMF Q4 with spark arrestor

RPM            A weight           C weight

2000             92 dB                 98 dB

6000             101 dB               105 dB

8000             106 dB                no test

By ear, the FMF Q4 sounded deeper, with the volume approximately the same as the stock exhaust.

So essentially, my results were very similar to danbartol's. The benefit of the FMF Q4 is lighter weight and a certified spark arrestor. The Q4 is no quieter and maybe louder than the stock exhaust with the kit baffle. (Although by Dan's testing it's quieter than the stock exhaust fully uncorked with no spark arrestor or baffle. That makes sense to me.)

Final shot of the installed FMF Q4 on my TE250. The Pirie CF Pipe guard took some modification to get to fit. I also removed the FMF stickers as they don't pay me to run their pipe ;-)

Spiegler Brake Lines and Leaking at the Crush Washers

Problem with Spiegler Lines leaking at the banjo bolts and crush washers.
I decided to put stainless steel braided brake lines on the GPz. I've done this on lots of bikes with great results. But it's definitely a job for a professional, don't mess with your brake lines unless you really know what you are doing.
In the past I have always used Galfer lines, but I'd heard good things about Spiegler and decided to try them.
Well... it ended up being a really hard project. The lines went on fine and bleeding was the normal big project. An important last step is to squeeze the brake lever very hard for several minutes and then to check the fittings for leaks: and my banjos were leaking! I double checked the torque specs and then tried a whole bunch of things to solve the leak, including over torquing the aluminum banjo bolts that Spiegler had provided. I searched the Internet and called Spiegler twice to confer. Nothing worked. Fluid leaked at the banjo bolt crush washers at several of the connections.
I was concerned about the aluminum banjo bolts. They where really cool, but you can stretch them and break them. I thought maybe they were stretching and not putting enough pressure on the washers. So I called Spiegler and ordered stainless steel banjo bolts and a bunch of new washers.
When the new bolts and washers arrived, it was a revelation... the new washers were different! I immediately called Spiegler back, and they confirmed the difference; they had gotten a bad batch of washers and I must have gotten them with my original shipment.
This picture shows the bad and good washer, and the obviously different profile.

 The thin washer is more easily crushed.

I could even feel the difference when tightening the banjo bolts with the good washers. When I tightened the banjo bolts with the bad washers my torque wrench quickly "clicked" but with the good washers I could feel the washer getting squished before I reached full torque.
And of course, with the good washers there were no leaks and the job was easily completed. Too bad I first wasted many hours with the bad washers.