Topic: newbie - 76 cb400f headlight issues / carb issues / front brake pad removal

[jp76cb400f]

Ive got a few newbie questions. There are probably answers in here somewhere but i couldnt find specifics.

1. Headlight and front markers are not working. Work as turn signals but the three lights arent on when bike is running. Lights in tach/speedo are functioning as are the warning lights and the tail/brake light and rear turn signals. I have checked all the connecions and the light bulb looks fine. I have been having some starter button issues - could that have something to do with it?

2. Just dissassembled the carbs - couldnt figure out how to remove the main jet. I think thats what its called. The brass piece in the center that the throttle needle goes into - again i am a newbie and need some dumbed down answers.

3. How do i remove old brake pads? The PO bled the whole system and disconnected the line from the caliper. I have taken off the two caliper pieces and tried to pry the pads off with a screw driver - bad idea. Do I just need to reload the system and push them off hydraulically?

Any help is appreciated. 

[TwoTired]

1.  The starter button normall interupts the headlight when pressed by depriving it of power.  It's quite possible the starter button malady is also causing Headlight/run light issues.

2. Main jet is at the bottom of the carb held in with a spring clip.  It has an o ring on it that should be soft and resilient to seal properly.  The needle jet/emulsion tube is pressed from the bore/throat and out the hole where the main jet sits.

3.I always push the piston out hydraulicly with the master cylinder lever.

Cheers,

[jp76cb400f]

Thanks for the help -

Just wondering - How do I get the tube out to clean it? Just pull? Do I have to twist?

Thanks.

[TwoTired]

Pull the main jet first, I use the spring clip to yank that. Only the o ring tension is holding it in at this point.
 The emulsion tube behind it is either very carefully pressed out from where the throttle needle inserts.  Or, if the carbs aren't too gummy, a shot of  compressed air into one of the air jets at the carb mouth will shoot the emulsion tube out of the carb body.  Catch it with something soft.

Cheers,

[jp76cb400f]

Thank you.

[Gordon]

None of my American model bikes ever had running lights on the front.  That is to say, the blinkers are just blinkers, so it may just be a bad headlight.   

[TwoTired]

None of my American model bikes ever had running lights on the front.  That is to say, the blinkers are just blinkers, so it may just be a bad headlight.   

I had a 75 CB400F with front run lights.  The wire diagrams show run lights on all CB400F models.  They only worked with low beam selected, though.

The CB550 series all had front run lights beginning in 1974 and continuing through 1978.

The CB750 series had front run lights beginning in 1971 (K1) and continuing through 1978. (According to the Honda shop manual wire diagrams, anyway.)

This applies to all American models.  So, Honda did supply the bikes with front run lights.  Keeping them working is a maintenence issue.

Cheers,

[dusterdude]

tt,i dont recollect my k1 having running lites,but since i dont have them on any longer im not for sure

[TwoTired]

tt,i dont recollect my k1 having running lites,but since i dont have them on any longer im not for sure

You're right I misread the Shop manual.  Run lights began with the Cb750 K4 (1974) model.  Sorry. 
The wire diagram is in the K1-K4 supplement but titled K4.

[dusterdude]

no sweat dude,im just happy to be correct for once

[jp76cb400f]

Turns out starter button was pushed in just enough to cut power to the lights but not operate the starter motor. Thanks for the help. I have another issue now though... I think my master cylinder is gunked. Took off rubber end piece that the lever makes contact with and there was rust and gunk all over the place. How do i crack that open and check all the seals?

Thanks for the help.

[TwoTired]

There is an internal snap ring inside the brake master.  Remove that, and all the guts come out the lever end.  Take notes or pictures of what comes out and in what order.  It has confused more than one person.

It is common for a leaking master cylinder to weep fluid into the switch housing. Inside that, there is a plastic housing for the starter button.  Brake fluid disintegrates that pastic.

Cheers,

[jp76cb400f]

Exactly where in the master? Sorry, very new at this.

THanks

[Bob Wessner]

I'm making the assumption your M/C is similar to the 750, could be wrong though, been known to happen  . Once the rubber boot and its round wire clip are out, if you look down in there, you should see the end loops of the circlip, part #25. These have to be compressed together slightly with circlip pliers to allow the circlip to come out of the recess in the master cylinder walls. Maybe this will help envision what's in there.

[jp76cb400f]

Thanks guys. Figured out the first two issues. Have a new post with my master cylinder rebuild ISSUES. I hate the master cylinder - may sink way low and just bring it in. But everything else on this restore has been pretty smooth for a first timer. Thanks again guys.