Dead RD400 resurrection

[JBeasty]

Here is my concern with the oil pump - I broke the pin off the smaller pump body casting (I thought it was push fit, it's threaded), the oil fittings are rusted bad, and the spring that pushes the pulley has disintegrated. I'll refer this post to Arrow and/or Ed Toomey when I message them. Maybe they can use it for parts if nothing else.

[JBeasty]

OK, I'm in contact with both Arrow and Ed Toomey (thanks Striker). Enough about the oil pump.
I've got the countershaft sprocket loose, the clutch nut loose (after getting the clutch tool), and now I'm having a hell of a time getting the nut loose on the primary drive gear. The Yamaha service manual has you shoving a rag between the primary gears, and the Haynes manual has you putting a rod through the eye of each connecting rod and putting wooden supports across the crankcase. Both of these methods seem really questionable. I gave each one a brief try, and the engine just wants to bounce and rock all over my bench. What's the trick to this? Heavy duty impact wrench?

[dgorms]

Stick a penny between the gears and use a rattle gun..............

[pidjones]

Stick a penny between the gears and use a rattle gun..............

Yes. If you don't have an air compressor,  Harbor Freight's Brauer 1/2" 110V electric ( https://www.harborfreight.com/85-amp-12-in-variable-speed-impact-wrench-with-rocker-switch-64120.html)  awesome torque for a $89.99 tool. Just make sure you pull the trigger to loosen. Got a feeling it would wring off wheel studs in the tighten direction.

[JBeasty]

Got the HF Bauer impact wrench and did the penny trick. Success! Thanks guys!!

[Striker1423]

I bought the first rendition of the HF Earthquake 1/2" battery impact. Things a tank. It laughs at wheel studs, and every other rusted on fastener it's seen. Bought it lets see, 5 years ago and charged the battery maybe 3 times total so far?

[JBeasty]

I bought the first rendition of the HF Earthquake 1/2" battery impact. Things a tank. It laughs at wheel studs, and every other rusted on fastener it's seen. Bought it lets see, 5 years ago and charged the battery maybe 3 times total so far?

Yeah, I was impressed. It was so quick, the engine didn't have a chance to jump around on my bench. I wasn't even sure it did anything until I checked and turned the nut by hand.

[JBeasty]

So I made an amateur move today...
I've got a vessel screwdriver with 6 various bits. I proceeded to gall up most of the screw heads for the change lever/cam stopper, and bearing stopper for the transmission. I then tried to use a screw extractor and had some success. I have 2 screws left that are pretty much stripped out on the heads. Before I proceed to screw things up worse, thought I'd see if anyone had some pearls of wisdom to share? I'm thinking heat might help, but don't I have to worry about trace oil igniting, or wrecking any plastic or rubber bits?

[JBeasty]

Never mind, I got those 2 last screws out using this little beauty:

[JBeasty]

My cases are pretty much glued together. I scraped off all the excess gasket goop I could get to. I've been "lightly striking" The upper (and Lower) cases, then not so lightly...   I've been googling splitting RD cases, but I keep landing on case splitter tools for vertical cases using the crank (obviously not gonna work on the RD). I've also tried tapping on studs and some reinstalled bolts. any other ideas?
Thanks for any input,
John
Also - note the bashed in area on the front of the case,  generator side.

[Striker1423]

Rubber mallet. Smack the front half of the bottom case while holding the top half up (Between the two long front bolt mounts). Do this in multiple areas. It'll come apart. The smashed part? Won't hurt it per say, just an odd location to have a dent?

[JBeasty]

Once again, Striker to the rescue this time! I beat on it in the front, and then beat on the rear with a dead blow mallet & piece of 2x4 along the overlapping edge. I also bashed in the lower mount for good measure  Probably should have used a rubber mallet like you said. When i get this all cleaned up, I'll need to find a good aluminum welder for 4 different holes and cracks in the upper, lower, and both side cases.

[Alain2]

Are the transmission gears all good?

[JBeasty]

Are the transmission gears all good?

As near as I can tell, they look near perfect (to my untrained eye). The gears have no signs of wear or damage. Just a few more things to dismantle, and I can start going through cleaning, inspecting, and making my list of parts to replace. I'm following the manual, but I don't have all the measuring tools yet. I have a digital micrometer, but need a dial gauge and...? I hope to get back to it tomorrow.
BTW, I took your advice and got plastic containers, zip-lock baggies, labels and a sharpie 

[Alain2]

Good job!