[spdracer71]

Recently picked up a very nice 1978 CB750 Hondamatic. Been sitting for awhile but still runs and the gas tank is perfect. (you can tell its been garaged most of its entire life) It does need a carb. clean because it needs to be running on choke to stay running.

What I would like to know is how the Hondamatic trans. is designed to work? I rode it around the yard. As soon as I shift it to 1st gear it wants to start moving forward. If you try to stop it with the brakes the motor will die. Is this normal? I would think that you can stop the bike in first gear and it shouldn't kill the motor??

Any help would be greatly appreciated.

Donny

 

[bmblebee]

I have a 1978 CBA. You are describing a carb issue. The bike should Idle, Accelerate and back to idle without shut off. The bike was also designed that when you shift to high from low gear, you can come to a stop and accelerate away in high range. They are neat bikes.

The trannys run on motor oil, they are early versions of trannys the automatic ATV's are running.

Does your parking brake work? Parking brake failure was a constant issue for almost every bike. It is the same part that fails and it is very difficult to find replacement parts

 

[SteveDotWorld]

The bike will change engine timing depending on what gear it’s in from 1st grear 7.5degrees BTDC to 2nd grear 15.5 BTDC. There is a specific stall RPM for each gear as well. As was mentioned before it’s a carb issue. Make sure they are clean/sync’d/adjusted correctly.
Getting a factory service manual will make life way easier.