Hi everyone!
The great news is this. My first attempt at rebuilding motors has my 400 back on the road last night. I have so far put 55 miles on the bike, no leaks, smokes, rattles, etc. Trying to keep it under 5000 rpm for the first 500 miles, but I will admit to running it up to 6500 a couple of times.
Here is my issue, so far. I have put a new set of UNI pods on the bike. The bike will cruise along quite happily at 4000 rpm and 40-50 mph at 1/4 throttle or so. If I get on the throttle at 4000, from 2/3'rds to W.O.T. the motor stumbles and bogs badly. Spinning back to 1/2 throttle or less and we are back purring. I checked the air screws on each carb, and here is what i initially found:
Carb 1&4: the screw stopper on the nut was almost exactly horizontal to the stopper cast into the carb.
Carb 2&3: the screw was turned "in" tight against the stopper cast in the carb. My understanding is that this means "richer".
These were the settings that they were left at before I disassembled the motor. I do not remember this hesitation problem before teardown, but that was over 2 years ago, so what do I know.
I readjusted all screws to 1/4 turn out from full rich, went for a quick ride (2 miles) and came back and pulled plugs. Here is what we find:
Plugs 1&4, lightly carboned up. I presume these 2 cylinders have been running rich?
Plugs 3&4, look perfect. Nice shade of gray on the tip, center electrode a nice light brown. If all my plugs looked this way, I suspect we might not be having this conversation.
So here goes, my first forray into carb tuning. I was warned away from pods, but I'm willing to give dialing them in a shot.
Where do I start? Could this all be in air screw adjustment?
Thanks!
John
