I've learned with the hardtail situations; have everything, I mean everything tacked/ mocked up, assembled, welded, before paint. It's one of those where you'll put it together and take it apart several times. Your son will know that machine inside and out! Haha Rear wheel spacing seems to be a battle too. Did you get a drum mag rear wheel? I have not fabbed up a caliper on a hardtail yet. I'll be watching this thread. Main reason I'm posting so I can find it haha. Don't know how much experience you have at this, also plan on a chain tensioner. I like the sprocket type over the skate board wheel. I definitely don't wanna come off like a know it all. Like wiring, you know you need. A tail light, brake light, etc. consider running the wiring in the chassis. It's the little things. Looks like fun! I'll keep watch. Straight pipes? These machines shake like a sum bitch. Blue loctite. The medium stuff, not satans blood that requires heat to remove. Haha