You're inspiring me to rework the K4 in my shed, just to see what it would do? I got a new piston set for it, so I made the first step.
I'm ambivalent about the paint, though. I've done a lot of them, some really well, some really...well...so I'd hate to wreck it at the end with a bad day of...painting.
I think I told this story before, but your gorgeous work makes me remember it again: during the first painting of the bike on the cover of the book, I had just finished the 5th layer (clearcoat) on the side covers and laid them onto the sawhorse to dry. It was twilight. Suddenly out of nowhere, a big cloud of gnats appeared, and kamikazied themselves straight into the left side cover, dissolving themselves into the paint as tiny little black specks, right in front of my eyes. I don't remember what I said (but that's probably a good thing), then went into the house...
Mark,I thought it was dry/less humid out there in Co. and you didn't get that.
It's definitely dry in Fall: somehow the gnats were still here! 
Ca. has been getting Alot of rain this past Winter;I'm waiting for it to get dry and the mosquitos to be gone completely because I want to spray 2K clear on a fuel tank and front fender.
I hope the clear coat doesn't attract those insects.. 
Bill, could you get away with erecting a small portable paint shed either at a friend's house or at your place?
You build 2x2 or 2x3 frame that is triangulated panels( a corner to corner diagonal reinforcing vertical to add rigidity and keep the frame work true. You can use a 1x2 for that if you can find some that are not warped. Basically build it out of the cheapest wood that will support a tall panel. You apply aadd a block at top and bottom to accept some 1/4" long bolts to go through these blocks that attach your walls and give you a 90 degree corner. You can use hardboard on the corners for gussets if you need to make your corners stronger easily... Just use constructuon adhesive and roofing nails to attach these corners applying adhesive to the frame not the gusset.then wing nuts and washers on your long 1/4 in bolts. You build yourself a forced air box fan double filtered and you tape it to the opening and you seal all around the filters with a tape you can remove but has enough tack to stay and not peal while you are using this. You stack two air filters on the suction side of the box fan and you tape them so nothing can get past them and if you add a ledge on your air intake panel of you wall that gets the fan up a bit and built into that wall with support brace so that side is well supported and cannot topple when you are building, you don't want the fan so high it interfere with your spraying. The booth you build will need to big enough for you to stand up and work in and you make it big enough for your panels to go up and down stairs or the elevator to store in your apartment. Heavy 10mil plastic will be more durable and buying a roll of it in 10 Ft by whatever length the box of plastic sheeting gives you enough material to tape down to the top of your durable paint booth. You lr roof is gonna be hanging your parts with heavy electrical wire to support your parts, unless you opt for something giving you an ability to rotate your parts and shoot it from all the angles you need in the booth for good coverage. A tank I would opt to spray the underside, let it cure with the first couple coats of the inside and underside and then a new can the next day shooting the top and better or money side... If you do a rotating stand I would use a rod to locate the front of the tank from side to side and then to keep it from backing off I would have a bolt go through the tank mount at the back of the tank. Get this high enough for you to work on spraying it from all the angles giving that consistent distance and one of those can grip spray handles is advisable, it uses a grip like a pistol grip locking into the can and your squeeze of the lever actuates the spray button. I find they give me good control and I don't have to worry about my finger slipping cause a sputter of the nozzle. Having the air intake to your back is a good idea, it keeps the air pushing the spray away from you and your body is taking most of the direct energy of the fan. Your exit is also going to have good filters catching the over spray and double filters there is a good idea too..I would tape myself in the booth with masking tape closing the booth overlapping flap and you need a secure cradle or way with table to put your spray gun when you come out of the booth and have your tape ready to seal the booth quickly after you have exited, as the odor of the paint or spray attracts gnats and other small bugs. You could even put a tube of plastic 20 inch box section style so you get that exit farther away from the actual spray booth and they gnats and flies and other small bugs attracted to organic solvents and paint would be around that exit instead of near your booth. You spray down the area in the booth before you enter with your parts, a spray bottle can suffice if you do it to pull the dust out of the air and any dust on the ground. Your tyvex spray suite taking the gloves to the suit and taping the legs to your shoes or your ankles to keep the urethane paint from making kin contact...it is a transdermal capable solvent and paint coating so respirator, and goggles or full mask with respirator. No exposed skin!!!!!!!!
You cannot play with this crap as it can kill you or mess you up once it has wrecked your body there is no cure...
If you leave a gap in the corner with your plastic you staple it to the frames and you could have two panels interlocking panels with one 10ft wide section of plastic. Or if you buy narrower than 10ft then you have more work sealing the roof to the sidewalks which means more step ladder work. If you build it so you can assemble it with two side panels and roof attached laid on its side then add the third panel to form a U shape, then you stand it up, adding some handles in the a panel or two it a good idea. Or you set a heavy pivot point item at the end of your open box you built on the ground, it fits between your walls and won't punch through the walls spike driven into ground near each corner and a section of )VC over that spike (rebar if on ground where you can drive it into the soil) or even really long threaded rod of big diameter or similar. Heck I've even seen 1" pvc be used as the frame, it just isn't as heavy duty and long lasting sometimes as a wooden frame with plastic stapled and I think they just used a lot of duct tape but I dismissed it and not sure how they did the plastic panel to panel. Basically a tapeneeds to be able to be cut or pulled off without damaging the plastic panels and it has to stick well enough and be secure so you don't have ingress points for bugs.
Having a tail of material at the bottom can allow you to take something and put a border around so you don't have to worry about your area you are painting. A sacrificial board or panel inside your booth is a good idea to set your paint gun, help I presume, or your spray cans in the case of spraymax urethane clear to set your fan pattern. A pot of warm water with maybe a hot pot going to give you hot water for immersing the can in to warm it up some for better flow, just don't overdo it on the heat, you want it warm, not hot...
A thermometer in your water bath for the can isn't an awful idea. You will need to shake it with the ball rattling for a long time so, a watch or clock with a second hand or phone displaying the clock with seconds is helpful. Starting a stopwatch after you spray a coat or a sharpie taped to a string suspended by a wall or flap so you can write the time so you know when you finished a part is a good idea. Unless you have a helper, always a good idea too. Your removable bar on the open U of your box on its side and you can erect it yourself then you add your last wall. Disassembly is much harder...
That could give you something that is going to be challenging to move but you disassemble it and cut the gussets if you used any and you sacrifice the plastic before disassembly. Then it is manageable for the move. You just set them on their sides in a long wall in your apartment and throw a sheet over the stack and it is behind your couch or wherever you put them.
Given you are in calicommi land I would use a sheet of plastic on the floor and a tarp over the plastic or a tarp floor so no one has any paint evidence against you wherever you setup the booth to do your paint work with the spray max.
Having your filtered air being blown in is safer than potentially having flammable exhaust, not that you would ever have that in Cali...right!
Go past a electric motor not designed for explosive atmospheres...
Anytime you mix flammable gases and enclosed spaces you risk things going poof or boom...both can ruin your day or your hearing or your hair do.... Have an extinguisher nearly ready to go, just in case, pin pulled already, you can always reinsert the pin on refillable extinguishers. A 5 pound CO2 would be ideal, but 5 pound properly rated for your situation if things went pear shaped. Amy one asks why you have one handy just tell them you like to be prepared for anything, just a good practice instilled in you as a boy scout. Hope for the best, plan for the worst.
