YZ125 spark arrestor rebuild

I went to repack my muffler (2002 yz125, stock exhaust) and found the inner perforated core was broken in 3 places. Has anyone had any luck purchasing replacement inner core? Motorsport sells 1", 1 1/4", 1 1/2", 1 3/4" and 2" perforated tube in 24" long sections. 

Unfortunately, the stock yz tube is 1 1/8" OD and I can't seam to find any suitable replacement. 

I bought the 1" OD tube from motorsport but it is much thicker wall than stock and much heavier. 

OEM replacement includes muffler end cap and stinger for $336, but is no longer available. eBay oem silencers run about $100, but they are likely to be just as ragged as what I have. Leaving the only viable option an aftermarket slip-on.

Hate to toss out the stock system over what amounts to few bucks of steel tubing.

Anyone found other repair options?

Thanks!