76 cb550k
head was decked twice but within clearance
port and polish
lapped not cut valves
stock cam and gear
stock carbs
4-2 exhaust
good points
good condenser
new plugs
good wires
good coils
when reassembling the cam in the head the C notch didnt align perfectly with the level of the head ex: C- instead of the 3 o clock portion of the notch meeting the level of the head, it was the 2 o clock position so the C notch was pitched forward a bit. now i struggled with the cam and gear and chain for about 2 hours tried 4 or 5 different ways to get the chain and cam and gear to line up at the 3 o clock position, and it was either the 2 o clock or 4 o clock position of the cam notch lining up with the level point of the head, so obviously after 2 hours of playing with it and not being able to achieve the 3 o clock position i figured it had to do with the head being decked and the clearance was enough to make the cam look out of spec, so i said bunk it. after assembly the tappets were adjusted to spec, carbs were rebuilt and super doooooper clean. with no pods or airbox the bike ran funky, so i timed it to the F mark on the timing plate which is 1/4 of an inch from the timing T mark. it ran, it revved, it hit redline. but it was sluggish, going up and coming back down. I tried vacuum syncing the carbs, i tried taking them off and just bench syncing them, i recleaned the carbs, the float height was checked and correct. reinstalled and the same problem, the bike will start, immediately rev up to 3k and just sound wrong and like its missing or like it doesnt have any guts. even after i installed my pods all the problems remained the same.
a friend of mine said lets just adjust it for the sake of doing it. on my timing plate there is the T then F then a 1-4 mark then two more notches. so if the T and F mark were at 12 o clock the other notches would be at about 2 o clock. after timing the bike to those other notches it almost seemed to run stronger. same issue, immediate rev up to 3k poor if any performance on a short ride, as soon as the idle drops below 3k the bike will die.
upon vacuum syncing the carbs the #4 carb seems to be this master carb where from all carbs being equal at 5psi at 3k any adjustment to give the #4 carb more psi raises the idle, adjustment to decrease the psi and the idle would drop down. i could get the bike to idle at 1100, however the #4 carb had about 3psi and all other carbs had about 6-7psi. the #4 carb also seems to have an issue where its getting gas, the cylinder is getting spark, #1 seems to be doing fine as the pipe is crazy hot, 2 and 3 are fine, but #4 is cold, it backfires from time to time, and it had this problem last year before i took the head off, but after a ride around the block/engine got warm #4 would come in strong and the bike would rip.
i have so far experimented with every possible combination of bench syncing, and timing, vacuum syncing, and timing, air screw adjustment, cleaning plugs, checking grounds and leads, point adjustment. everything short of taking the head off again.
im open to any suggestions, bestow your knowledge of awesome bike problems and fixits to me. because i feel like this could be stumping the best of them right now.
thanks!
