Author Topic: CB750 Carburetor Removal and Instalation  (Read 911 times)

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Offline twright3

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CB750 Carburetor Removal and Instalation
« on: November 24, 2023, 08:29:15 PM »
Here are hints that worked for me:
Removal
- Put the bike on its center stand or a lift to be level.
- When removing the tank, remove the filter cup and PUSH the gas lines off the fittings with a screwdriver.
- Remember to disconnect the throttle cables. (Obviously, remove the air filter.)
- When removing the velocity stack housing, loosen the clamps until the ends are about to separate.
- The housing should come off fairly easily because this part of the carburetor is smooth.
- The carburetors will separate from the (black) manifolds, not the manifolds from the engine.
- Loosen the rear manifold clamps until the ends are about to separate.
- Move them up by the forward clamps.
- It can't hurt to try to get some penetrating oil at the rear of the manifolds.
- Heat the manifolds with a heat gun.
- Straddle the bike, grasp the carburetors and yank them vigorously up and down with a little tugging.
- No go? Use leverage; get a piece of wood .5"x1.5"x4". The thickness is roughly the maximum.
- On the right side use the wood to protect the fins, Any lever will do to push on the carburetor bar.
- On the left side the choke is in the way so use the indicated hole.
- Any lever that fits will do. If it's too difficult, get a longer lever.
Installation
- Put lube on the outside of the carburetor lips and the inside of the manifolds.
- Heat the manifolds with a heat gun.
- Get the carburetors inserted enough in the manifolds to stay there.
- Use leverage as in the photos. 2"x4" boards work well.
- Get one side at least 1/2 way in. Then get the other well in. Go forth as needed till they're home.
- Or use two levers and a friend.
I found this install method gave a really comfortable feeling of total control over the process.

Offline newday777

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Re: CB750 Carburetor Removal and Instalation
« Reply #1 on: November 29, 2023, 02:26:57 AM »
You mentioned photos, but apparently you missed attachments of them??

On the install of the carbs, I've found that along with the heating of the rubbers and a little red rubber grease, to use a ratchet strap around the head and over the 4 air inlets of the carbs to equalize the pressure. It just takes just a little pressure of the ratchet strap while moving the heat gun constantly not to burn the intake rubbers and the carbs will pop in place easily.
This picture is on a fresh dirty barn find K8 bike doing a startup making sure the motor sounds good, using a set of clean K5 carbs that I have on hand.
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A