Great job, and as a high school shop teacher I think it's even sweeter that it was done as a HS project! Gorgeous!. I'll never forget the first time I fired my 71 commando after about a 25 year hibernation.......awesome AND I'll never forget my wife's face when it actually fired because she never thought that pile of parts and rust would fire: well done! To Mr. French, who really cares if it's not original? just enjoy the kids' work.
Exhaust head pipe bluing is from to lean or to rich condition. Yes should have had a fan on the engine when running it to long! A fresh engine should be ran up to running temp and shut down. Let cool and done again to running temp and let cool. Then retork the head bolts. Great looking bike and Great build guys!!
Very nice. Cute with the loose mirror and partway through tightening something else down. Also, the gas tank and rear fender were moving about - loose too. Making sure all the bolts are tight and torqued in a 2-year project requires a marking system.
Five years and not one followup video? Still, I presume you resurrected this from a "basket case," so well done, and I hope you've just been too busy enjoying it. I don't think they made any 850s in '72 though--just the flaky higher compression "Combat" 750s. I had a '72 the '80s--an old surplus British police bike "Interpol" model. Currently its successor, my old daily driver of the '90s, is sitting in a shed awaiting its own resurrection--one of those old '67 N15CS "Desert Sled" hybrids I got "most of" when I lived down in Texas, and then cobbled together the rest from found bits, including parts from a broken Sears Lady Kenmore washing machine. I'm sure 'll get around to it "soon", but just now I'm having some fun with a 2005 Royal Enfield 500 Bullet in military trim I picked up recently. Great little old school single cylinder thumper. It looks like it maybe crawled out unscathed from the Battle of the Bulge, but is actually the most recently made vehicle I own. They just kept cobbling pretty much the same model together decade after decade after decade at a factory in India long after the original English parent company had gone bust. Over there they've got the same sort of traditionalist national pride vibe as a Harley here...almost like a cult. There's even a Hindu shrine to one in Rajasthan called "Bullet Baba." Anyhow, thanks for sharing the big day!
You need to direct a big fan at your engine when tuning for more than 3 to 5 minutes. Your 8 minute video actually showed the head pipes changing color during that time. All in all a great job of obvious craftsmanship. I would pay for permission to copy that custom color scheme.