collector box mod

[HARTLESS]

so today I  decided I wanted to experience what my fj sounded like with the stock silencers taken off, and just the collector box muffling the sound.....not a good idea.....not because of any catastrophic event, but because it sounded bad to the bone (just to loud(I live in an apartment)). I took her for a spin around the block and it gave me a bit of modititus.....I got to thinking about removing the canister silencers, and making a silencer that replaces the collector box...has anyone ever done this? is it not a good idea? opinions? I do have to admit that it looked a little weird without the canisters....

p.s.
KOOKALOOOOOOOO!!!!

[Firehawk068]

I had to laugh when I read this post...................I did the same thing back when I was about to put my Kerker 4-into-1 system on............

Factory System
1990 Yamaha FJ1200 Stock Exhaust

With Muffler cans removed
1990 Yamaha FJ1200 exhaust with stock Silencer cans removed

With collector box removed
1990 Yamaha FJ1200 exhaust with collector box removed

With new Kerker system installed.
1990 Yamaha FJ1200 exhaust with Kerker 4-into-1 system

On a side note:
When I removed the factory system, I weighed each piece as I took it off.  I then weighed each piece of the new Kerker system..........Once I added them all up, and subtracted the weight of the new system, I was amazed at the weight savings after switching! 45 lbs difference between the two!

[HARTLESS]

I had to laugh when I read this post...................I did the same thing back when I was about to put my Kerker 4-into-1 system on............

Factory System
1990 Yamaha FJ1200 Stock Exhaust

With Muffler cans removed
1990 Yamaha FJ1200 exhaust with stock Silencer cans removed

With collector box removed
1990 Yamaha FJ1200 exhaust with collector box removed

With new Kerker system installed.
1990 Yamaha FJ1200 exhaust with Kerker 4-into-1 system

On a side note:
When I removed the factory system, I weighed each piece as I took it off.  I then weighed each piece of the new Kerker system..........Once I added them all up, and subtracted the weight of the new system, I was amazed at the weight savings after switching! 45 lbs difference between the two!

the really funny thing is I have watched those videos a couple times and they are what made me do it!!! I was wondering who it was.....

[keand3]

That Kerker 4-1 system, as far as I know these are not made to fit the FJ. Is that system still in production?
Just out of curiosity, what did you need to do to fit it? The sound it's just awesome!!

Cheers
Ken

[Firehawk068]

That Kerker 4-1 system, as far as I know these are not made to fit the FJ. Is that system still in production?
Just out of curiosity, what did you need to do to fit it? The sound it's just awesome!!

Cheers
Ken

It is an FJ-specific system..............however, the design of it allowed the muffler to hang off the back of the mid-pipe with no support..........It left the bike last year during the gunnison rally...........


I found a suitable replacement that was a better design, that put the support bracket on the muffler can itself........I shortened the midpipe to bolt the muffler to the rear footpeg support, now all is well (I hope)



The original system is no longer in production.......When I bought it, some dealer in the northwest had a few of these leftover, new in the box, so I bought one...........That was 4 years ago........

[Firehawk068]

the really funny thing is I have watched those videos a couple times and they are what made me do it!!! I was wondering who it was.....

The videos don't really transfer the sound appropriately...................Maybe if you watch them on your surround-sound, and crank it up to 9, you'll get an idea of how loud it really was..............................

[keand3]

the really funny thing is I have watched those videos a couple times and they are what made me do it!!! I was wondering who it was.....

The videos don't really transfer the sound appropriately...................Maybe if you watch them on your surround-sound, and crank it up to 9, you'll get an idea of how loud it really was..............................

I might just do that 

This might be off-topic but what kind of rear rim is that on your bike?  To me it looks like an FZR rim, but i am not sure. Like the brake rotor!

[HARTLESS]

I have an idea that might be dumb.....but if I put a light packing of muffler glass in the collector would it block airflow and cause too much backpressure? or would it work? I have never torn one apart so I don't know how the passage is...

[Antonn3]

H Hartless, you would not be getting any benefits.
The collectors on our bikes are similar to a resonator on a car.
The resonator uses the internal cavity to reflect sound waves that cancel each other out, reducing the sound. The collector is hollow.
In a car, that is a 4 to 6 DB reduction in sound, which is a lot.
As for the packing material placed within the collector, it would do nothing, especially if packed in lightly (sound wise), pack it in tighter and you increase back pressure.
In a muffler, your exhaust flow goes through a perforated pipe, surrounded with the packing material, it is not placed within the flow of the exhaust gases.
By placing it within the collector, you'd burn/blow it out.
Some exhaust systems do use  metal baffles only, to cancel the sound waves.

Tony

[Firehawk068]

The rear wheel is off an FZR1000-Exup model..................1992 I believe.
The rotor is a Galfer Wave Rotor............

Putting glass packing in the collector would only cause backpressure(if you could keep it in there somehow) The exhaust would blow it right out I'm sure.....
The inside of the muffler can is a straight-through perforated pipe(as Antonn stated). No baffles in it whatsoever..........
The glass packing is packed all around it, in between the perforated pipe and the spun aluminum body...........at lower rpm's is absorbs some of the higher pitch noise frequencies, but at high rpm and WOT it doesn't do much  for sound reduction.................It's pretty loud.

[HARTLESS]

Haha yea that was kind of stupid, I thought about that as I was posting. Oh well, but ill figure something out. Right now I've got dibs on a set of hyabusa pipes for 20-30 bucks so I might just fab those up....:-D

I like the color of your wheels btw, I'm going to try and find a metallic gold for mine

[fintip]

I don't doubt you, but I am curious. I have seen you claim elsewhere that exhaust upgrade drops 45 pounds, but assumed it was a faulty estimate after Randy posted that the stock system weighed 35 lbs and that his will weigh 6 lbs maybe in production (10 lbs prototype).

Did the exhausts get heavier on later years, and he was weighing an '86 while you were weighing a '90? Where is this discrepancy coming from? Both of your numbers sound reliable.



I ask because I have quoted both at this page: http://fjowners.wikidot.com/lighter

And I'd like to have a more definite answer.

[Firehawk068]

I'll have to see if I can dig up my notes from back when I switched to the new exhaust................if I can only remember where I put them?
I need to make me an FJ binder one of these days

[fintip]

Just use mine. It's online and viewable/editable by anyone.

[Firehawk068]

OK, I have to clarify this weight difference thing..................And apologize for posting some misinformation

I went back and double-checked my notes on the exhaust swap.......

The weight savings is 21 lbs!

I am not sure where I got the 45lb figure from, but I know I posted it in at least 2 different places...........Sorry everyone if I led you astray...........
Disregard all references to a 45lb weight savings, and use the researched 21lb figure!

As you were.....