Rusty rear motor mount frame section 97 FLHT

Man what a surprize. Ignition module(made in Japan stamped on it) went after 11 years started this long over due project. Wound up with bare frame to get to the rust found hidding inside rear frame mounts for rubber vibration isolators. Where the steel mounts bolt to frame the threaded lugs in frame section area was a mess. Required a bunch of grinding and welding to repair. Dont know if you have ever run across this but Im told its a common problem thats not caught in time in most cases. It's from the inside out, so when you see a hole its not the only one believe me. There were bleed holes from factory that allowed water in but not at bottom to let out. When I got done I left one bleed hole at bottom on both sides. I sprayed rust kill solution into void. I was a Nuclear Certified Welder for over 20 years. Small area such as that is hard to seal weld , it will build pressure from heat and blow weld puddle onto your welding lense. Ill will post some pics tomorrow, to late tonight. I wound up repainting frame then doing all the things an eleven year old bike needs. Swing arm bottom where you cant see or get too also rusty as hell. Oil pan hides the very front of it. New stainless Brake lines all round, pads. New Andrews Cam,Top end tear down, Replaced the damn leaky paper gaskets with James metal on cyclinders and Rocker Box's, Accel Programable ignition Kit, wires, plugs, super coil, single fire. Carb recal kit, Vance Hines true duels into Porker Straight Pipes. Wheel Bearings, Seals, Motor Mounts, Push Rod Tubes, Lots of other odds and ends and what ever else needed. Oh yea, Nice stage 1 Arlen Ness breather. No more plastic crap in the way to adjust carb and much better preformance. Also changed out useless air temp gauge in dash for OEM Oil Temp gauge used on twin cam dressers, it will work on the 97, you have to provide a place in oil pan for sending unit. My chrome trim ring fit gauge also. Same face in black as other gauges.
With top end removed was able to walk bottom end assembled out of frame with Primary and Trans whole. Used 2 floor jacks, wood blocks and some red neck shade tree engineering. Back in same way, not a scratch on new paint.
Broke in new cam after a couple test rides blasting 2 hrs each way to Daytona to pick up a new 2 lb Carbon Fiber Helmet, dot cert too. Bike ran real nice. Lots more power. EV26 Andrews cam. Sweet with stock heads on evo. 2000 rpm to 6000 now is strong pull all the way.
First time tank has ever been off this bike, some rusty places under there to but just surface. Florida for ya. I live 2 miles from beach and parked at Nuc Plant when I worked, its on barrier island. Not to often due to salt but enough evidently. Any body interested ask questions and Ill try and help. If you have this frame design beware of hidden rust.
JP

Correction of Cam Info

In my post on rusty frame I stated I used Andrews EV26. Incorrect, I used Andrews EV27 Cam sorry for the oops. Still very pleased with its preformance.

New to this so forgive me if this is a goofy question. Since this has weep holes up top and none in the bottom (before you left some), could you not make the repairs and then shoot the hollow full of Great Stuff Foam or some similiar compound? Great Stuff was developed to stop and displace water. Don't know of it being harmful to metals. Again not sure just asking.

Goup in void

Thats one option.
From a welder's point of view, should this area ever need repair in the future you have injected something that wont clean out or allow welding. It would heat up and boil, run out, steam, burn, contaminate weld,make big mess, choke welder. If I did anything else after repair I would seal weep hole with dab of caulk to seal out oxygen. No air,no rust. If it needed repair later, the little bit of sealant in weep hole would not cause problem. Anyone with this frame, I think they were 1992 through 1998, a flash light and inspection mirror in and around the rear motor mount bolting points to frame and swing arm pivot points and under swing arm where its over oil tank and you cant get to it or see it with out tear down of rear of bike, removale of swing arm and removal of battery box and rear fender also gives some access. If you see rust on inspection, it needs tear down. If it needs real work like mine, bare frame is a must. Only way to access all the way around for strong, correct repair. Grind out bad areas and reweld back to original configuration. Once I got all loose rust out by beating on hollow area with hammer and weld repair was completed I flooded inside this area with rust killer sealer several times. It can be picked up at any parts house, ask at desk. It kills rust and seals over it (no oxygen) and turns black when done. It is liquid acid base, pretty much nasty too on humans. Wont eat solid steel, just the rust. Its paintable once it turns black. Comes in spray bomb. Several brands. It works. Dont get in eyes, on skin, or breath. Concrete floor was etched after I was done.
I worked in a Twin Unit 1000 MW Nuclear Plant for 26 yrs, Mechanic/Certified Welder. We used to have guys bring aluminium to be welded and they would bead blast first thinking doing welder a favor. Cilica impregnated in metal would not weld along with salt corrosion. When you light off with 200 amps AC on Aluminum that crap just Boils and poops, fissle, a real mess. Only way to fix if metal was thick enough was weld and grind it out over and over untill all contamination boiled out. We had huge weld shop in Nuclear Plant on the Barrier Island Ft Pierce Fl. Guys with corroded boat parts were an endless stream. We put sign on our bead blaster, see welders before use and locked doors to prevent damage to blaster or ruining good aluminum from blasting with cilica.
Every Biker with old bikes needs buddy thats a welder.