Maybe some of you have tried already. The Aluminum basket on my DT 250B is worn after 32000Km. I purchased a NOS basket, but the gear drive doesn´t match to my primary gear wheel. Obviously the basket is being 3 parts riveted together with 3 bolts. My question: is it possible the divide the 3 parts, so I can use the new Aluminum basket with the old gear drive? How could the bolts be removed without damaging any parts ? (pressing, heat.. ?).
Looking forward for your answers.

I'd go back to using the old one despite the slight wear marks & especially if it was working normally. Otherwise maybe get the matching crank gear & then if it alters your overall gearing by enough to bother you just change the final drive sprocket by a tooth one way or other depending. Looks like the new one has a tooth or two more so lower gearing at the front sprocket so add a tooth to that might be about right. Actually that's probably overdoing it [one tooth] but maths isn't my strong point. I've got a clutch drum from an RM250 that i'll get a pic of sometime & you'll be impressed [not] as it's about 1/4 of the way across in how far it's grooved but surprisingly still operated ok but really was very 'past it'

Found my RM one. Ok, not 1/4 way across but pretty bad lol.

Ok, I just did it because the new basket was there anyway. First bored the 8mm rivets, then the clutch is split. I ordered new rivets 8 x 20mm and made the half-round head flat on my lathe (head 12,5mm diameter x 2.4mm thick) After I made a tool, where the rivets heads have molds to fit in. Whole clutch is strained into the tool to bring basket against the counter plate. There is a coup spring which has to be 100% strained flat, otherwise the distance bushings over the rivets have clearance. Then hammer the rivets half-round and finally take care, they do not look over the gear wheel . Hope I could help somebody, who wants to do the same.
Tool is for sale including 3 rivets...

part 2

There ya go! Good work