EXHAUST HOLE

[kerrbss]

where do i drill that washer out at? i have that iowa spree with the restriction in the exhaust. where do i drill it out at?

[devenex]

As I understand, it should be at the engine end of the pipe. BUT there are some Iowa pipes (like mine) that don't have a washer, but longer narrow stretch at the beginning of the pipe.

The quickest way to know (unless you have the muffler off already) is to check against pics on the internet, as the kind with a washer is exactly the same design as a stock muffler.

[SprEE*MP*]

HUH??? what washer? where? how? what does drilling it do?

[Kenny_McCormic]

Sometimes there is one n the header.

[kerrbss]

pic please

[wilsoniya]

pic please

The scoot in my sig had a restricted exhaust. There is a thick washer (probably 0.25" thick) welded just inside the head pipe. This washer effectively makes the entire exhaust 'narrower' by limiting the gas flow. As such, it increases back pressure, limiting overall engine performance.

Unfortunately, I haven't seen a pic of this washer anywhere, but this might suffice:


This was the first mod I ever did to my scoot, and really the first mechanical task ever for me. It's a very easy job that will take about 30-45 minutes with a dremel and a few grinding bits. Even though it's easy, it's quite beneficial--I saw a dramatic performance increase (note your top end won't improve if your pulley (aka variator) is restricted).

Conveniently for you, my exhaust was rusted to s*** and the muffler actually fell off whilst riding (but that's a whole other story), and as such I ordered a new stock exhaust, which will more than likely mean I'll have to de-restrict it. If the new exhaust actually has the restrictive washer in place, I'll document the derestriction process with a bunch of pics.

[wilsoniya]

This is your muffler:


Before:


After:


What I used to do the job--an el-cheapo Dremel and some grinding stones of varying sizes:


Any questions?

[ALOW1]

This is your muffler:


Before:


After:


What I used to do the job--an el-cheapo Dremel and some grinding stones of varying sizes:


Any questions?

One of the Mod's needs to sticky this

[MotorMaker]

Put this in Tech Docs please

[wilsoniya]

Put this in Tech Docs please

There's more where this came from! I went all discovery channel and took a bunch of pics and videos while I was working. I was planning on putting up a Tech Docs thread, but I wanted to post a few pics here, too.