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Not sure if this should go here or the "Show Off" section, but wanted to show my crank that was rebuilt by Marc (aka 1976RD400C).  It was way out of spec and had a bent connecting rod - he put in some new connecting rods and bearings, trued it all up, and got all the work done in just a few days. It will be until Spring before I get it running, but so far it's looking good!

I've done lots of 400 cranks if anyone needs one done at a bargain price.

Where in NY are you located? Might have to take you up on that

Wait, so you're telling me it's not good luck to put a penny in the clutch housing???  (yes, was my poor man's method to loosen the primary gear nut)

I'll get some cheapy amazon special dial gauges to measure the crank's endplay.  But assuming it's not way out of tolerance, I have to think the seal just wasn't seated properly in the grooves in the crankcase and that's what caused it to get dislodged. Just want to make sure I avoid making the same mistake when I re-assemble.

Had my engine out of the frame while doing some body work and repainting, figured I'd take a look at how things are looking on the inside. Turns out the crank seal behind the primary gear is all chewed up. Well, good thing I found this before I did more damage.

(1) What could cause this other than incorrect installation? Could issues with the crank (out of balance, out of spec) cause it?

(2) Think I know the answer, but could I replace that seal without splitting cases? Even if I can, imagine I'll need to look to make sure there aren't bits of rubber floating around near the transmission.

They're good for carbs and carb parts (jets, gaskets, etc), spark plugs/wires/boots (they carry BR8ES), uni pods/filters and general purpose stuff for your bike (bar end mirrors, oils, grips, levers).  But you won't find anything specific to your bike that you'd find on Partzilla or Economy.

Came across this 1 hr 44 min long video of Stan Lipert re-assembling an RD400 motor with little explanatory prompts throughout, including him designing and fabbing his own chambers!  Super valuable resource!

FYI there's a 'how to' on testing the autolube pump on the forum:  http://www.2strokeworld.net/forum/index.php?topic=1119.0

Good to see Chuck in there!

The last few times I've pulled the oil line hose off the carb, the whole nozzle comes out as well, which worries me it might wiggle itself out while riding (and no oil --> bad day). I can likely mess with the brass press fitting piece on the nozzle to expand it a bit (or get new nozzles), but wondering if a more permanent solution might be to just drill/tap the injector hole and use a threaded brass barb fitting instead.  Can't think of a risk other than it leaking or vibrating out, but if done right with a suitable gasket/crush washer and loctited, seems it'd work just fine.  But if this was a better solution, imagine the wise engineers at Mikuni would've already done this. Any issues I'm not thinking of?

What happens when you throw a Hayabusa engine in a tiny Fiat 500?

Looks like they'll let you watch 30 mins for free without an account
https://www.vicetv.com/en_us/video/blood-and-wire-onitas-fmw

Another consideration is what type of riding you do.  I live in the city I do mostly 20-30 mph riding, and to be honest, the chambers make it kind of a pain. I have to get up to 7k RPM to hit the powerband, so I'm constantly revving high to get it moving, then stop 10 seconds later at the next light/stop sign, meanwhile pissing off everyone on the street, scaring dogs, making babies cry, etc. I've never had stock pipes on my bike, but from what I've heard, they would've let me have just as much fun but at lower RPMs better suited for the city riding that I do.  But, if you're going to be riding at higher speeds for extended stretches, the relative lack of low end power might not be a big factor for you.

FYI if you go with the Vape, Chuck (SUPERTUNE) did a great write up that walks through the process in excellent detail. Even with my limited mechanical knowledge and skills,  I was able to use that to install it with no hiccups. http://www.2strokeworld.net/forum/index.php?topic=855.0

If the nearby city you're referring to is NYC, yes, they're definitely around.  I don't know if "terrorizing" is the right term, but they do ride pretty recklessly (ignoring stoplights, weaving around cars, riding in parks) and ride in groups that can seem threatening to non-riders.  They're definitely loud and annoying...but so is my RD.

My biggest issue is that, because of them, the NYPD have declared an overall war on motorcycles. Since the dirt bikers have no problem running from the cops, the law abiding motorcyclists who stop and pull over are the ones that get ticketed/towed for minor infractions (aftermarket parts, not properly signaling, expired inspection stickers, etc) to show the public that they're 'cracking down'.

You can take a look at the jetting poll for ideas:

https://docs.google.com/spreadsheets/d/1T9KaGS9cCZbq9JfwybwA-co3t1NmSuT4D0GfrSjBrJs/edit?usp=sharing

and submit an entry yourself to help others:
https://forms.gle/WWjCHhmdfmozznhWA

Got it.

Related but unrelated question: (within the acceptable range of airscrew turns) is there any benefit to using a larger pilot jet, or is that just wasted gas?

Hypothetical ex:
(1) Airscrew: 1 turn, pilot 37.5
(2) Airscrew: 2 turns, pilot 40

Assuming that 1 and 2 both have the same optimal fuel/air ratio, would having more fuel+air from setup #2 have better performance/torque at low speeds over #1? Common sense seems to imply that more gas = bigger bang, but not sure it's that simple.