The OD is 1 1/2 inches.

Still up in the air whether I am going to try to do something with this or not.
I'll contact a muffler shop and see if they have any suggestions and get a quote. Also going to contact the ebay seller to see what my options are.

Thanks for the suggestions everyone. If I do end up keeping it, I'll post results.

 

It's the same as my RSV head pipe then.

There aren't any mega bombs here in the Philippines on anything. I'll have to try one just for the fun of it, maybe it'll start a new trend. I can have one sent to my shipper in AZ


Walker makes a 1.5 - 1.5 connector part no 41919), but it's 4" long, probably too long for your connection

The mid pipe I stole off my XR200 is one size smaller, so it slipped into my 1.5" and clamped up with no problem. A slight size reduction at the joint but it's all I had available and the exhaust really woke the bike up nicely.

 

FWIW Their patent (Patent US7510050 - Vehicle exhaust systems - Google Patents) shows that inside the bomb the pipe has 1-3 small holes in it.

Different than the China pipe's completely open bomb section which is mounted further forward as well

 

I was just looking at that walker connector. I'd need to hack off some length to make it work either way. What's a few more inches?
I also found this connector on ebay. It's stainless steel, slotted and comes with the clamps.
1 1 2" Exhaust Pipe Coupler Joiner to 1 5 8 in Pipe No Welding Stainless Steel | eBay

 

Isn't the ebay piece a little large on one end?

 

Not sure. It's confusing the way it is worded. I'm hoping that this quote means the way I interpret it. "It fits any 1 1/2 inch up to 1 5/8 inch car or truck application or import car 40mm application."
I'm thinking this means it has an 1/8 inch leeway for pipe size.
The pic looks like it is one continuous size end to end.

Either way...once again I am going to guinea pig it.

 

You guys with megabombs from either source have to rejet after you installed it?

 

Someone please correct me if I'm wrong, but I think that rejetting would be unneccessary in this case. That is unless you were really lean to begin with. A slight adjustment of the air/fuel mixture screw should take care of any changes from adding the larger header.

Ohh yeah, don't bother getting that ebay connector from post #36. Will not work. It's 5 inches long. It would need to be shortened alot to fit the straight section of the pipes. There isn't any way to shorten it due to the way it is designed. Back to the drawing board. Still have a couple more ideas I'm looking into.

 

If the large bomb section is letting the cylinder evacuate faster/better (think expansion chamber) then you might be getting a stronger inlet vacuum as a result, which could change your jetting requirements.

I added a homemade cross over pipe to a car and gained .25 seconds at the strip. Same idea, letting exhaust gases escape better. It was a fuel injected car so I didn't have to alter the jetting manually.

For your megabomb install, just use a piece of 1.5"ID tubing. Probably buying a connector at the local auto parts, cutting off the 1.5"ID section, and slotting it at each end. Or a local muffler shop might be able to swedge a piece of 1.5"OD out to ID if their machinery can handle exhaust that small

 

Or flair one end or the other to slip fit over each other, maybe not even clamp on.

If both pipes are equal OD, get a piece of tubing that will slip over both and clamp.