Where are the plugs?

[ebrammer252]

I'm going to look at an 81 CB750F this Wednesday I would like to compression check it. How hard is it to get to the plugs on the 81 750F? What all does it require to get to them? Also, what kind of numbers should I be looking for?

Thanks!

 

[ebrammer252]

Also any special things to remember when compression testing a 750?

 

[dirtdigger]

Plugs are on top of engine under the spark plug caps. Tank will need to be removed to get access to the inner two cylinders. Spark plug socket only thing needed to remove plugs. Dissable ignition, hold throttle wide open, cranking pressure should be 170psi per Honda manual but 130 to 160 range and it should run decent.

 

[ebrammer252]

I'm trying to remember how I removed the tank on the old 73 CB450 I used to have, I want to say it had rubber bumpers where it just lifted off but I can't remember, same thing? What do you mean by disable the ignition?

 

[dirtdigger]

Remove the seat then one bolt on back of tank then pull it back after unhooking fuel line. You need to disable the ignition so when you are cranking it over the plug wire wont make spark and also keep the motor from starting. Easy way....once the tank is off you will see the coils....unplug one of the small primary wires from each of the coils...no more spark.

 

[ebrammer252]

Remove the seat then one bolt on back of tank then pull it back after unhooking fuel line. You need to disable the ignition so when you are cranking it over the plug wire wont make spark and also keep the motor from starting. Easy way....once the tank is off you will see the coils....unplug one of the small primary wires from each of the coils...no more spark.

Assuming the 750 has an external petcock couldn't I simply turn the fuel off and let the engine run itself dry to avoid the engine turning over as well?