Yoshimura Rock Baffle

[FJ1200W]

Greetings everyone, hope you're well.
Getting right to the story, I'm taking the baffle out of the Yoshimura muffler.
Why?
Why ask why?
Better flow, I talked with one of those engineers, while a neat design, it's restrictive.
I wanted something that flowed a little better, and if it sounds good, it's win win!
It's on order, and delivered for well under $20.00 without having to leave the farm.
I'm happy.
I'll be happier if it works.

[Millietant]

Steve,

Just be wary that with only the link pipe being attached to the exhaust hanger, there's nothing holding the can in place other than its joint with the the link pipe (basically, the perforated tube)

As a couple of people on here have learned, that could lead to a disappearing end can mid-journey (the infamous Kerker's). Unfortunately, the piece that breaks is not something you can see, to check every ride - if you can, it might be worth fabricating an additional bracket for the "silencer" too. 

[great white]

Fixed my "vintage" Kerkers like so:





Besides doing away with the "can cracking" and subsequent "can departure" issue, it also allowed me to pull the can in nice and tight and as high as I can get them. Not too difficult to weld on a tab to mount to the OEM rubber bushed mounting points.

And here's a pic someone posted on one of my threads with the infamous "can departure":



I'd be a little cautious with making straight through pipes though.

Most people think louder means more power, but that's not always the case when talking about small engines. They're usually designed so the exhaust works with a certain amount of flow restriction in order to improve scavenging, which improves power delivery. The engineers who designed the engine designed it as a system, from the airbox to the exhaust tip. If changes are made to one component in the system, it usually requires changes in other parts of the system in order to optimize the entire system (IE: power, drive-ability, etc). It can be a involved as the baffling and chambering designs inside the can itself, or it can be as simple as a specific shaped rear cone on the muffler and/or hole size that create just the right amount of flow restriction.

Adding to the confusion is that it's also not always "intuitive" as to what to change and how. For example; I've changed exhausts before to freer flowing units, which would logically seem to need a larger jet. But Many often require a smaller jet, which is opposite what you would think would logically be the case. the issue is the increased airflow often leads to a "stronger" signal in the carb throats, which draws more fuel and makes for a rich condition, requiring a drop in jet sizes or a change in needle position. To make it even more perplexing, that's not always the case with all engine systems. If you're not an engineer with a bank of supercomputers behind you, changing parts like this and getting an improvement is often hit or miss or a bit of "black magic"....

[FJ1200W]

Good input, thank you.

The Yoshi system has a really stout bracket, see below.

And it uses far thicker metals than my Kerker system, and I am grateful they have not broken off. Sure would like the tips, maybe someday.

The quality of the fasteners and engineering for strength seems to be up to the task.

I'll leave the fiberglass in place, just so if anyone asks, I can say, without being dishonest, about it having packing material 

Everything fits together extremely tightly, I had to bust out the medium hammer and chisel. 

[FJ1200W]

The stock baffle was designed to meet the period noise requirements, not for performance, or so I was told by an engineer that worked for them at that time.

The new pipe with open it up about a half an inch in diameter, or so. The tip has a smaller tip inside, that will not be there any longer and the tip will truly be the tip.

The muffler body seems to be of a thicker and better quality of aluminum than my Kerker, I could be wrong.

As for it being noisy, I'm good with that. I'm hoping to use this on the 1314 engine I've been working on since the pyramids were built.......

It's going to appreciate the flow.

Until it blow -

(JUST KIDDING!)

[FJ1200W]

Rock Auto delivery came as promised.

Everything fit perfectly. I'll only need to shorter it an inch or three.

Yahoo!

[Pat Conlon]

What we learned on the (multiple) departure of the Kerker cans, is that the location of the support bracket in front of the can is the problem.
The can itself needs supporting....not the pipe in front of the can.
Without can support (like Great White did ^^^nice job btw) the can becomes a dynamic cantilevered load that over stresses the joint at forward end of the can. Dynamic load because of the movement. The worst case condition.

A beefy tostada hanger welded to the pipe at the front end of the can, does not help this situation.

[FJ1200W]

I must be lucky. I put 30,000 hard miles on mine with the Kerker cans with any issues.
Chalk it up to luck I guess.
Today I finished up the Yoshi canister.
I purposely used stainless steel Phillips head screws with high temp locktite just to piss myself off the next time I take it apart.
Probably to out the baffle back in because it's too loud! (not)

[Old Rider]

Great work looks solid to me.You should name the baffle yousihmura eliminator.Loud pipes saves lives 

[FJ1200W]

Right out of the gate, I want to make it clear.

You were right and I was wrong

Admittedly so.

"What?" you might ask -

It's loud. Too loud.

Now that we're past that, those pet potty pads are the best thing since beer.

Exhaust is on, had to trim the lower cowl.

It's been a good day!

[gdfj12]

Steve, apology accepted. Looks like you use Amsoil. Nice.

Now, continue with the moditis treatment. Keep modding.?


George D

[FJ1200W]

1st real ride.

I really do like a few things about this pipe. First being, it is so loud, I rode very, very, sedately.

Once it was opened up, and the sound changes dramatically when it "comes on the pipe" and it really does seem to make good power above 7500RPMS, without a discernable loss down low.

How the ceramic coating works and holds up will take time.

The mid pipe will come off again, as a couple of dents in key places will make the rear brake work better and another point that's just a hair too close for me near the center stand.

Once it's been beat up, it will be wrapped and sprayed with some black hi-temp  silicone coating.

Good times are hear again - and the forks are working better than ever.

Combined with the repacked steering head bearings, life is good.

[FJ1200W]

Another road test completed without issue.
Other than being LAF.
I'm pretty pleased with the look.

[FJ1200W]

Yoshimura baffle in place, so much quieter.

Voltage regulator installed as well and seems to be performing as it should.

A good day, this Friday the 13th!