Homemade Muffler Suggestions

[YetiWoodz]

So the front of my muffler as you can see has a 1" pipe attached to a funnel. A solid metal plate with 4 holes similiar to the perforated one in the pic is placed on that. It's 6.5" in diameter. Obviously this isn't as smooth of flow as if I had something like this.

So is that part of my muffler considered "bad" backpressure (restriction, overall worse) or "goodish" backpressure (more low end torque, less top end)? I put a shorter intake, velocity stack, and rejetted my carb to optimal and put my muffler on at the same time so I can't tell what the muffler is doing. Any thoughts?

 

[Wrench]

No restrictions I can see, looks fine.
Kinda looks like a BBQ grill can ya cook hot dogs on it too?

 

[YetiWoodz]

No restrictions I can see, looks fine.
Kinda looks like a BBQ grill can ya cook hot dogs on it too?

I just want to clarify, the metal plate attached to the funnel has no tiny holes like the one in the pic does, only the 4 big 1" holes. You probably understood that but I just wanna make sure, so still, no restrictions?

 

[Wrench]

Yea, you got good exhaust air flow. You won't have any unwanted back pressure.
Yeti your a creative kinda guy. What can you design for the intake?

 

[YetiWoodz]

Ok, cool thanks. Well, once I get my bike running, (I need a new wheel bearing). I'm gonna test my rpms and frequencies and use them to design a proper boost bottle/intake resonator.

 

[YetiWoodz]

And I can use those frequencies to also design a helmholtz resonator for my exhaust to get an even deeper tone through frequency range cancellation. I can make use of my stock muffler for that.

 

[CrazyDan]

As long as the muffler flows better than the stinger it shouldn't affect performance much. The return wave occurs before the stinger. As long as the muffler flows better than the stinger then there should be minimal losses.

 

[Frogslayer]

Does it really stay cool enough to not melt that zip tie that's holding it on?

 

[YetiWoodz]

Does it really stay cool enough to not melt that zip tie that's holding it on?

Yup. That surprised me. Then I looked at the package of the insulation and it says it acts as a heat barrier. And since there's so much in it, it stays very cool.

 

[YetiWoodz]

So I noticed my muffler was a lot louder than usual and yellow stuff was oozing out of under the foil tape that's sealing the seams. I took off the foil tape and the muffler cement was all over the place. And the packing in my muffler is now yellow instead of white. I ran my finger inside the expansion chamber and my finger was covered in oil. I have more packing for my muffler, that's not a problem. What I'm worried about is the 1 of 2 possibilities. The one I'm worried about is before, my carb was spewing out fuel because of the hole in the float. So my crankcase may be filled with fuel. Or its from running rich because putting on the expansion chamber made it run rich. But I feel the second one is unlikely because I changed the jet to the correct size at the same time I put on my muffler and that's also when the fuel started spewing out. What could be the culprit? Unless I'm still running rich idk I don't hear 4 stroking.