Hey all, I apologize in advance if these are noobish questions; I'm not a motorcyclist; I just like crazy stuff that's fun to ride. Here's the story for anyone interested - tldr; at the end.
I purchased a quad with grizzly plastics and a modified (presumably previously wrecked) Seca ii frame, engine and fairing. The charging system was shot - it would run fine with a jump box but stumbled something fierce once the charging system was left on its own. While I waited for parts, I took apart the carburetors, dunked them in a heated ultrasonic cleaner for a couple hours and threw an ebay rebuild kit at them. (floats, float needles, and fresh CV vacuum boots in the tops) Right now, the airbox is still off, and I have the boots soaking in hot water to get them malleable enough to slip over the carbs. I did the same trick for the lower intake boots and it worked like a dream.
It runs well; but seems to only want to start and stay running with partial choke when its cold. once it's idled for a few minutes, It'll idle at around 900-1100 RPM with the choke closed. The minute I touch the throttle, it dies, choke or no choke. I also found that with the choke open full, it'll run up to 6500 RPM and hold that, but I didn't do that for long since the engine was still cold. It will also occasionally spit a fuel mist from the inside carb on the left side and the outside carb on the right side but it's a quick puff, and the bike doesn't stumble or stall. seems like with no choke, it's got too much airflow and with any choke, too much fuel. Is this observation consistent with how these bikes normally function, and would this behavior be remedied once the airbox is installed?
One last thing, the original vacuum fuel pump and fuel tank petcock were packed with varnish. I was able to remove the internals of the petcock and clean it out to restore fuel flow (at the cost of no more prime or fuel kill) but the fuel pump was just too far gone. Corrosion everywhere, bad lines, etc. My (probably short term) repair was to wire in a lawnmower fuel pump that I had on hand, an electric pulse-type pump that runs from 4-7 PSI and an inline filter to catch any junk that might be left in the tank. I suspect this is a bit strong for these carburetors, as the right two carburetors will begin to vent, but the left carburetors won't. The left carburetors do have fuel; I can gently blow into their vent and fuel will seep out of the intake.
TLDR; is the airbox necessary for these bikes to run well?
Is it normal for the bike to die immediately after applying any throttle with the airbox removed?
Is it normal for the left two carburetors to fill more slowly compared to the right two carburetors?
Does the fuel tank have a return nipple that I can tee into?
The engine seems to be air cooled; you folks are probably largely riding on the street, but can the engine still effectively cool itself running hard on dirt?
Is Honda HP-4 10W40 a good choice of oil for these bikes?
