Author Topic: first ride: 1976 CB750F. now tuning / charging issues (Read 9135 times)

riffman12 · « **Reply #50 on:** June 07, 2016, 11:22:15 AM »

hm well now I'm confused again. If I follow those directions it takes me to section "D"

If you follow from there, the only possible "end points" are a fault RR (which is brand new in my case) or a stator / rotor problem. It doesn't seem to point you toward any wiring problems or ignition switch circuit like in the other sections.

riffman12 · « **Reply #51 on:** June 07, 2016, 03:27:34 PM »

OK this evening I will be following that guide. As I poke around at old threads I found this post:

Quote from: Bodi on April 09, 2011, 09:46:01 AM

The Dyna takes about 10 watts of power for its electronics and it has a very short dwell angle so both coils are on almost all the time, quite a lot more average load than the points system.
The alternator has very little extra power: with a dead stock bike and a healthy charging circuit it's only capable of charging the battery above 3000 RPM or so.
With the Dyna you can't also have a high wattage headlight or extra lighting. If you've put in an H4 headlight with a 50W+ lamp you're in trouble, the battery will never charge. You won't get stranded but you won't be using the electric start. You can get 35/35W bulbs that aren't as bright but still better than the feeble stock headlight.

Has anyone heard of this?

I have both an H4 bulb and (i believe) Dyna electronic ignition

przjohn · « **Reply #52 on:** June 07, 2016, 04:01:25 PM »

How did this go 3 pages? How about some method troubleshooting from square one.

riffman12 · « **Reply #53 on:** June 08, 2016, 11:57:03 AM »

Quote from: przjohn on June 07, 2016, 04:01:25 PM

How did this go 3 pages? How about some method troubleshooting from square one.

I'm awful with electronics so it's been a learning experience. I will be method troubleshooting from here on out, but the last couple of days I've been trying to make sure all my connections are good.

Stupid question: last night i tested some voltages without my 55W H4 headlight on and obviously the numbers were higher.

When we test voltages at different RPM ranges on these bikes, should the headlight be on or off? or does it not make a difference?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #54 on:** June 08, 2016, 03:49:12 PM »

Some of US can not turn off the headlight short of removing the bulb or fuse which is also an option when your battery is getting low and you're on a ride. That is just one way to see the draw of the bulb and the results with it off. Test with it on. Your voltage regulator should take care of the drop.

riffman12 · « **Reply #55 on:** June 12, 2016, 09:08:38 AM »

Big thanks to calj737 and everyone else who gave me a hand with this.

I tested voltage drop at various components (ignition switch, headlight, left and right hand switches etc) and nothing seemed to be too big of an issue.

So yesterday I continued cleaning grounds and connections around the coils under the tank. I'm not sure which one it was exactly, but something must have worked because suddenly I was getting too much charge back to the battery

I gave Cal a call and he was nice enough to guide me through a few tests to figure out what was going on.

In the end, he had me wire the black from my reg/rec directly to my positive battery wire at my starter solenoid, bypassing any possible hangups in the 40 yr old harness.

Now the battery seems to be charging perfectly, at least on garage rev tests. This afternoon I'm going to take it for another ride and see how it goes. I'll report back.

Thanks again guys

Jerry Rxman Griffin aka MuthaF'er · « **Reply #56 on:** June 12, 2016, 09:15:08 AM »

Congrats to you AND Cal. Hard work rewards good results. Is a new harness in the works?

Ride and enjoy!!

Jerry Rxman Griffin aka MuthaF'er · « **Reply #57 on:** June 12, 2016, 01:33:37 PM »

So what's your take on the regulator side?

I had forgotten I now have a jumper wire in my tool box rather than straight to the battery as you had him do. That's a good trick at times. Nothing a whole new wiring system won't fix LOL

riffman12 · « **Reply #58 on:** June 12, 2016, 07:20:45 PM »

so I got some riding in today and the bike ran awesome. Smooth through the whole rpm range, pulls from all the way down low. Here's my plugs after some mixed riding. What do you guys think? I'll be doing a proper wide open plug chop later. Most of this was from 1/4 to 1/2 throttle.

closeup of #4:

Jerry Rxman Griffin aka MuthaF'er · « **Reply #59 on:** June 12, 2016, 07:25:45 PM »

Show off!

riffman12 · « **Reply #60 on:** June 13, 2016, 08:53:05 AM »

ha thanks guys. I thought they looked pretty good. #2 is possibly a hair richer than the others, but hard to say.

As this was mostly putting around town, I think next step is to put new plugs in and do a full throttle chop and make sure my 115 mains are working well with my exhaust / K&N airbox setup

flybox1 · « **Reply #61 on:** June 13, 2016, 10:16:21 AM »

Quote from: riffman12 on June 12, 2016, 07:20:45 PM

so I got some riding in today and the bike ran awesome. Smooth through the whole rpm range, pulls from all the way down low. Here's my plugs after some mixed riding. What do you guys think? I'll be doing a proper wide open plug chop later. Most of this was from 1/4 to 1/2 throttle.

closeup of #4:

Hot D@mn!!! those are some nice looking plugs

Jerry Rxman Griffin aka MuthaF'er · « **Reply #62 on:** June 13, 2016, 06:34:41 PM »

Without digging through the thread have you done a proper sync? Could even up the plug color just that little bit more.

scottly · « **Reply #63 on:** June 13, 2016, 06:59:08 PM »

Quote from: riffman12 on June 12, 2016, 09:08:38 AM

Big thanks to calj737 and everyone else who gave me a hand with this.

In the end, he had me wire the black from my reg/rec directly to my positive battery wire at my starter solenoid, bypassing any possible hangups in the 40 yr old harness.

This was only for testing, correct? If left connected directly to the battery, the field coil will always be energized, draining the battery when the motor isn't running.

riffman12 · « **Reply #64 on:** June 13, 2016, 09:35:06 PM »

ha funny you should say that. I was about to come on here and post that my battery is dead after sitting over night

So it sounds like that can't be a permanent solution...

riffman12 · « **Reply #65 on:** June 14, 2016, 09:14:07 AM »

ah yes my never ending electrical gremlins. I had one day of sweet riding and now back to cleaning $:-\$

Tonight I'm going to clean the main frame ground even though it looks spotless - just to rule that out. The other ground I cleaned was by the coils where they mount to the frame. Any other grounds I should be aware of and cleaning?

Then from there, given my symptoms, do you guys think the culprit connection is somewhere in my black wire circuit? Or could it be anywhere?

riffman12 · « **Reply #66 on:** June 14, 2016, 09:30:38 PM »

so I was poking around the harness and found this junction between the airbox and the oil tank. I believe it's where the electronic ignition is wired into the harness along with the the rear brake light switch:

Looks like someone used that little red 3 way clamp between the 3 black wires. Is that an ok way to connect these wires? Looks kind of hack to me...

Wondering if that could be the hang up in my system, but if so: What would be a better way to join those 3 wires?

scottly · « **Reply #67 on:** June 14, 2016, 09:44:02 PM »

Quote from: calj737 on June 14, 2016, 05:04:04 AM

Yep, Scottly's right. That's a mistake on my part.

Okay, Scottly, then how does he eliminate the 0.5v drop through BLACK? He's cleaned every connector from the battery through the chagrinning and key switches... With that drop, he's over-charging his battery (15.1v).

Like you said, a 0.5V drop is about as good as it gets for the stock harness. If the voltage drop on the ground side is not at fault (measured from the battery negative post to the green regulator wire), then one could wire a relay to switch the regulator black lead directly to battery plus, using the black harness wire to trigger the relay coil.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #68 on:** June 15, 2016, 02:55:33 PM »

Looks like the power tap for my Dyna III ignition. If that thing has CUT the wire then you may have found your problem. Voltage check before and after.

scottly · « **Reply #69 on:** June 15, 2016, 07:32:13 PM »

Mike, I'll reply to your PM here, so others can learn also.
To do the positive side voltage drop test to the regulator, it's best (and easiest) to measure the drop directly, with everything connected.
Connect the meter red lead to the battery + terminal. (the terminal itself, not the wire connected to it)
Connect the black meter lead to the regulator black wire, at the junction between the harness and the reg.
With the key on, kill switch set to off, read the voltage.

To read the negative side drop, connect the black meter lead to the battery - terminal, and the red lead to the green reg wire, and read the voltage.

riffman12 · « **Reply #70 on:** June 16, 2016, 08:59:13 AM »

ok thanks guys.

Scottly, I'll give that a go.

At the moment, I can't really test my system. After my coils drained my battery the other night, I've been using my battery tender to bring it back to life. Went out last night after charging it all day, and there was acid seeping out of the cracks on top of the battery. The battery its self was quite warm.

Is that battery toast? Or is this normal?

Might just order one of those Scorpion AGM batteries

b52bombardier1 · « **Reply #71 on:** June 16, 2016, 01:23:30 PM »

Save your money on buying a new AGM battery until you have the charging system sorted out. An AGM battery is even less tolerant of overcharging than a flooded lead acid battery. The AGM will soon start to fail, bulge out the sides of the case and become difficult to remove from the battery box.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk

riffman12 · « **Reply #72 on:** June 19, 2016, 08:29:42 PM »

ok quick update. With the help of Bodi (from another thread) and Cal, I was able to wire a relay into my charging system to bypass the resistance in the 40 yr old harness.

Now I'm getting 12.5 V at 1000 rpm. 14.5 V at 5000+ rpm.

Looks to be good so far. Does anyone know if there are any negative long term issues with this setup?

News:

Author Topic: first ride: 1976 CB750F. now tuning / charging issues (Read 9135 times)