I've had my JH600 for barely a month, and have done all my riding on the stock bike. A Laser ProDuro Sport muffler that I bought from Franki even before I had the bike has been sitting in my living room. I got around to finding an installer today. Let me say this was no ordinary installer. This guy was a genius with an acetylene torch. His wife was no slouch either.

We've all marveled at Pfaelzer's amazing modifications, and this thread makes no effort to challenge his. In fact, I'm merely copying one of his many mods -- swapping out the 8.5kg stock muffler with a ligher, higher-performance model. But I took a bunch of pictures in what turned out to be a pretty picturesque setting, and thought the process might be both entertaining and, in the case of TexasAggie and others considering this modification, useful.

I found this guy through word of mouth, via a friend who runs a nice little gear shop in Shanghai. I'll give him a shameless plug here...

Qiyi Motorcycle Accessories

A motorcycling friend of his has a tiny shop selling ceremonial red eggs. These are used to celebrate the naming of babies when they are about a month old, i.e., pretty likely to survive the vicissitudes of expulsion from the womb. You get the idea from his little reception room that this guy is no ordinary red egg dealer.



OK, his red egg shop is in an innocent looking street called Jiaoji Lu, in Shanghai's northern Putuo district. In fact, his red egg shop is the anomaly here. Virtually all the other several hundred businesses revolve around pretty much one thing: scooters. In the course of about five hours in his shop, untold numbers of scooters scooted in, mainly for muffler repair but also other bizarre mods. If you don't want to see a lot of pictures extraneous to the muffler installation, this is not the thread for you.

That's Mister Muffler in the cool shades, in the classic posture of Chinese street industry -- squatting. As I said, he's good with the torch, and is not ashamed to take any work. So when I arrived he was carving up slabs of steel plate. I'm guessing this was 2cm stock. That's the red egg shop on the right.



Mister Muffler's sign advertises a variety of metallurgical services, but his main stock in trade clearly is mufflers.





I pulled out my ProDuro Sport, and he cradled it in his hands like it was a newborn. We didn't discuss a price. Without a word he got down to work, pulling off my right side panel to reveal what looks more like a WWII torpedo than a muffler.



You'll recall Pfaelzer removed the entire pipe to the cylinder so as to preserve the stock muffler in all its glory. I greenlighted Mister Muffler to have his way with mine. He chose to do her with a grinder.



Now that's more like it!



He took a few measurements. As you can see, the fitting on the ProDuro is 7cm in diameter, while the pipe is only maybe 3cm. It's a slip-on muffler with a clamp, so he quickly found some stainless stock about 8cm in length but it was a bit bigger than 7cm across. No worries, just slice it down the side and reweld it to the proper diameter, and grind it smooth.





The next step is more complex. How to create a funnel-like step-down section to transition from 7cm to 3cm? Using only a caliper, a bladed compass, a ruler and a punch, Mister Muffler dug deep into his high-school geometry lessons and started mapping the piece. Still squatting on his shop floor, of course. No paper or pencil. No computer or calculator.













Look carefully. You'll see he's got everything etched neatly on the tin surface, like a latter-day Leonardo.



Now all that's left is to cut it out.



Better step outside.



Say, who's that in the blue? Yes, that's Missus Mister Muffler. She works there too, and as I said earlier she's no slouch with the torch either. In fact, though Mister Muffler was called away by insistent customers several times, it was Missus Mister Muffler who handled virtually all the other muffler repairs today.

This looks ugly.



No worries!













stay tuned....