Work Done and Work Ahead...1976 Super Sport

[Thfireman]

When I took delivery of this CB750F Super Sport it was located 85 miles from my house.  My Wife and I went up to look at it and decided to buy it.  It was running and I drove it home.  Visually it is in A+ condition.  Mechanical wise it is in running condition.. But:

It starts first time then idles smooth for a minute then speeds up, slows down, skips and pops ocasionally.  After warm up I take it on the road and it boggs if I accelerate rapidly but is smoother with slow easy acceleration.  At cruising speed it runs steady with a lag feeling from time to time and some hesitation.  If I try to open it up it boggs then takes off and will pop from time to time.  Now after it is warm it will stall at idle if I do not pump throttle while at a light or stop sign.

OK,  So I have had it a week and here is what I have done so far:

I added Seafoam to a full tank of fuel when I picked the bike up and drove it home.  Smokes under acceleration and it may be the seafoam.  It didnt do it when I test rode it.

When I got it home I pulled the tank and air filter box.
I took the carbs off and opened the bowls.  Red dirty gas was in bowls, some sediment.
I took jets off, pulled the float valves and and blasted all holes with cleaner, cleaned jets and floats and reasembled the carbs.  I didnt go into the tops of the carbs.
One of the float needles had the spring top jammed on the needle and I couldnt get it to move.  The needle valve was moving freely.
I checked the fuel tank for trash and drained a bit of fuel from the petcock and it was clean.
I replaced the fuel filter (inline)
The bike was reassembled.

It started and smoked and popped.  I took it for a ride and it runs about the same.  

I have ordered 4 card rebuild kits.

Observations:  I sprayed starter fluid over the intake boots and the engine began to speed up.  I noticed the boots are hard and drawn up.  They dont seal in the air box and they are too short to connect to the carbs correctly.

I have ordered 4 new intake boots.  

I havent adjusted valves yet but I replaced the plugs.

After the rebuild and the boot replacemnt and valve adjust what else can you all suggest that I do to get this bike in better running condition?

Thanks, Roger

[Rick V]

It sounds like you are on the right track,but I am not sure which carb boots you are replacing. The ones between the carbs and head will be the more important ones because if they are cracked the engine will run lean.The other thing that you should check are the ignition points. Be sure they are clean and gapped correctly at .014 inches. Once that is done check the timing.If you have to move the backing plate to adjust the timing recheck the point gap again as  it will usually change because the clearance between the plate and the crankcase will allow the plate to move around when you rotate it.
Rick

[Thfireman]

It is the soft rubber boots located between the airfilter box and the carb.  Noth the thicker insulator boots that hook the carb to the engine.  Those seem to be fine.  I sprayed ether around those with no idle change but when sprayed arount the air box it went high idle..Leak!

As for the ignition,  I will get in there to check them soon but I have to get a timing light first and get the carbs rebuilt first.  Thanks for the gap and setting info.