Still got that fricken bug.

[Bill Seward]

I'll start the bike, warm it up for a bit, then go to take off.

The bike will run fine, until I either shut the throttle down to coast a bit, or to pull in the clutch to upshift. Then all heck breaks loose. The tach will jump up as the bike seems to shut off and turn on rapidly for a second or two. After it settles down, it runs fine till the next time I chop the throttle. Same thing happens..

After about a mile of this, the problem completely stops, the bike runs normally.
If I shut the bike down for a bit, it starts and runs with no problem. It only seems to happen when the bike has been off for a long time, like 6 or 8 hours. If it's really hot out the problem, while still there, is noticeably less pronounced than when it's a cooler day.

The bike cranks over fine, and with the Series regulator and a new stator, is getting excellent charge voltage.

Battery terminals are clean and tight. It is an older battery though. I'm thinking that there is possibly some sort of intermittent problem in one of the cells, which maybe breaks continuity inside the battery, making it act like it is disconnected?

Main fuse was replaced with a good Delco inline holder, and a good quality fuse. I have seen those cheap Chinese fuses you can buy on Ebay deform and lose contact. There also is a good fuse holder in the line from the regulator to battery.

I thought I cleaned all the grounds to frame well, but to shut the whole thing down for an instant like it does makes me think it is something else. Jon Harris gave me a good ignition switch, which is in the bike now. Wiggling the key will not duplicate the problem.

Any ideas? or suggestions?

 

[Fire-medic]

I think you may have mentioned the possible diagnostic you need. I would hook a voltmeter to the main circuit, between the battery + and the main battery cable, that should be easy to fabricate. Then monitor the battery voltmeter to see if there is a 'cutout' when you have the issue, which would indicate you have an issue w/unimpeded current & causing the drop in voltage.

Someone who is wiser than me in electrical theory may suggest you don't have to wire it in-line, that you can wire it parallel. To my way of thinking though that wouldn't reveal the change in output from the battery, which is what you suspect is the issue.

Another thing you may wish to try is to remove any ground wires, hook a continuity tester to each end, and then continually flex the cable along its length, and give a good 'yank' on each end termination, to discover if you have a below-the-insulation break in the conductive wire, or the ring terminal, or other cable end. Once in awhile, I've found a rotten stranded wire not-visible to the eye, inside the pvc insulation sheathing, or a corroded cable termination that is again, inside the pvc insulation, next-to the cable/wire termination fitting.

 

[D-Max2012]

Be careful wiring a meter "In Line" or In Series, with the battery.

Most meters are not designed to handle that type of current passing thru them, especially at start-up. In parallel should be fine to get a reading. If there is a dead cell, or intermittent issue, your meter will show a value change.

Take a look at what its reading normally and compare what its reading when its acting up. Of course you'd have to feel the cut out, then glance down at the meter when it's happening.

Be careful taking your eye off the road..
Good luck.

 

[Bill Seward]

I've got an onboard led voltmeter mounted to the handlebar clamp. It does reset sometimes when the bike acts up. I'm gonna have to start checking ground cables, and the one I'm thinking of is the main battery to frame one. That would definitely shut things off if there is a defect. Also movement of the bikes battery and other parts when I chop the throttle could flex something to cause the problem... I could borrow the ground cable from my mower to test this out. All the wiring on the bike is pretty old. I'll bet that's the cause of the problem.

 

[D-Max2012]

That sounds reasonable to assume that, since you did notice the LED meter resets, when things start acting up.

I'd start the bike, then start mimicking stresses by pulling or shifting any wire, that can move at all.

Chances are you'll be able to find it..

Good luck with that.

 

[Fire-medic]

Yes, thanks for the word of caution about running that-many amps through the meter, I wasn't sure if that would be the safest, so if just running parallel would reveal the cutout in the continuity of voltage delivery, that's the 'safe way' to try this.

Be careful wiring a meter "In Line" or In Series, with the battery.

Most meters are not designed to handle that type of current passing thru them, especially at start-up. In parallel should be fine to get a reading. If there is a dead cell, or intermittent issue, your meter will show a value change.

Take a look at what its reading normally and compare what its reading when its acting up. Of course you'd have to feel the cut out, then glance down at the meter when it's happening.

Be careful taking your eye off the road..
Good luck.