The fenders are from Domiracer. They still have the correct 160 Monza Jr rear fender (top left) in stock, along with a less expensive stainless steel generic fender. I went with the NOS part (but ended up not using it)..
There is an interference issue when trying to use an earlier rounded fender on a later square fendered bike because the rounded fender doesn't have a relief for the newer style battery tray. I suppose you could put a relief (aka dent) in the fender, but the battery tray can be easily modified to solve this by shortening the tabs. Cut off the part that's bent upward, then bend the remaining part of the tabs upward to replace what you just cut off. The problem with this is, now the battery tray is shorter and I have no idea if there is a battery that will fit the shorter tray. You might want to check that out before modifying the tray!
Another option is to replace the stock tray. Since I had a 250 Monza to copy, I made up a new tray based on the one from the bigger bike. The modified original tray and copy of the 250 tray are shown in the bottom left photo. In the photo the 250 tray looks too short, but it' s not in the right position yet - it will work fine. I do need to do a little clean up on it, it's literally still a bit rough around the edges. After cutting out the new tray, I realized the tray in the 250 isn't centered. Mine is... which means at full travel the chain guard could hit the tabs for the battery strap. Luckily I hadn't welded anything together before I figured that out, so I raised the tray and shortened the tabs a little. Next time I'll offset the tray, but this will work too.
The red front fender is from an 85cc Bronco. I had planned on removing the valance panels, but changed my mind once I saw it in place. I like the look, especially with the new "capped" headlight trim ring. I modified the brackets to pull the fender in closer to the tire. Luckily there was enough material on the mounting tab to simply cut some off and drill a new hole. Note the "Ducati" decal on the fender. Steve at Bevel Heaven carries these. He's got the good stuff, with seperate letters intead of the one piece junk that some other places sell. Don't buy the cheap ones, they aren't worth it. (If a picture of the decal shows part number 00189, it's the cheap one)
I didn't like the non-valanced rear fender with the valanced front fender. I thought I might just have to live with it, but I was lucky enough to find an NOS Bronco 125 rear fender. It's similar to the Monza Jr, fender, but valanced. When I tried to fit it on the bike I found that shape is slightly different so there were some minor tweaks that needed to be made to get it to fit. The biggest change is the mounting holes in the side need to be moved back about an inch and up slightly to line up with the tabs on the frame. Also, the fender is narrower than the Monza part because it has no bracket, so I'll need to make some spacers. I'm happy about this as it moves the fender away from the seat mounts. I was worried about them scratching the fender when installing/removing the seat, but now it looks like it's the spacers that will take the abuse.