Electrical problems

[TarMack]

Looking for some help:

I bought a Hawk 250 last year. Changed oil, adjusted valves, bled brakes, stiffened forks, full exhaust, Nibi carb, beefier chain and sprockets... all before starting it. Got it working pretty well. 1200 miles on it. Went for a 6 hour adventure ride. Bike running great. Stop at mountain top for photos. 30 min later, turn on key and nothing. No lights. Found battery swollen. Bike did start and got me home.

New battery installed, no lights work. Bike runs. Any ideas???

Thanks,

Darin

[TominMO]

Check fuses, check electrical connector tightness throughout the harness.

[Crossbar]

Electric start work or did you have to kick start it?

[david3921]

Check voltage at the battery while running. Should be at 14 to 14.5v. If higher, than rec/reg is bad and frying your battery and maybe burnt out your lights if incandescent.

[TarMack]

Electric start works with new battery installed. No lights work. Lights are all LED.

[Thumper]

The fact that your electric starter button feeds power to the starter solenoid and the bike starts means that the main fuse is OK. The CDI is getting power with key on, and the starter relay is getting power from the starter button. So if I am interpreting your post right, your lights must be a separate issue.

Another way to say this is that power from the same circuit that powers the CDI, headlights and turn signal flasher unit are common (fused together on the main fuse). And it starts, so the main circuit is OK.

For the turn signals, the flasher unit is powered all the time when the key is on. The power goes out of the flasher unit to the turn signal control switch and power then goes to left or right turn signal led lights "power in" side, and the led lights are grounded on their second wiring lead. Note that unlike incandescent lights, led lights won't work if power/ground wires are reversed.

So when the turn signal switch is in left position, The flasher passes power transiently (flashes) through the turn signal switch to front and rear turn signals (left). The front and rear turn signals usually have an independent ground but check the harness to see where they ground. So the flasher unit should be powered all the time when the key is on, and it passes power through the turn signal switch when you select left, or right turn signals. You can check that the flasher unit is getting power when you turn on the key. Then you can check the grounds. An ohmmeter can verify that the ground leads at the turn signal LEDs are grounded (or they won't work).

For the headlight, it is a similar story, but the headlight switch on the left controls should be powered when the key is on. And, the power passes through the on/off switch to the hi/lo beam selector. From the hi/lo selector, it powers the headlamp directly (hi or lo input, usually through an H4 connector). The headlight has a ground lead that you can test for proper grounding with an ohmmeter. That would be the third pole on the H4 connector.

I think you probably have a bad ground on the lighting system (or loose ground connector), but you can check for input power (key on) at the flasher unit and in the multiwire plug that goes to the lighting control unit (handlebar lighting switch cluster). The turn signal switch (input) and the headlight switch should BOTH have 12V when the key is on.

[zero_dgz]

Originally Posted by Thumper

For the headlight, it is a similar story, but the headlight switch on the left controls should be powered when the key is on. And, the power passes through the on/off switch to the hi/lo beam selector. From the hi/lo selector, it powers the headlamp directly (hi or lo input, usually an H4 connector). The headlight has a ground lead that you can test for proper grounding with an ohmmeter. That would be the third pole on the H4 connector.

I will never pass up an opportunity to trot out my interactive motorcycle turn signal circuit diagram. You're 100% correct with all of the above.


I second the notion that something is disconnected or -- given the state of the battery as described -- possibly melted. Anything we say here is by nature just going to be spitballing; the only way to actually figure out these types of electrical issues is to grab your multimeter and start checking for voltage at the appropriate connectors or continuity in the wires in the harness, starting at the bulb sockets and working backwards until the break is found. IIRC the Hawk and Hawk-alikes do not have any relays in the electrical system except the turn signal flasher, if you want to call that a relay. Everything else is a mechanical switch, and main 12v power to all the accessories is simply switched at the ignition cylinder without any intervening componentry. So I would start there, if it were me.

[TarMack]

Thanks Thumper and Zero. Keep in mind problems started with a swollen battery. I fear the regulator / rectifier was feeding too much volage to the battery and fried something or everything. I will use info provided and dig in soon.

[Thumper]

I came from automotive electrical systems where relays include the horn, headlights, and of course the starter solenoid. The flasher unit is a relay of sorts

But these Chinese bikes don't bother with a headlight relay or horn relay (might be an exception here or there). Another diversion is that a replacement horn I recently installed wasn't polar-no designated ground. Low wattage "meeper".

Well, that certainly simplifies wiring. And YES zero_dgz you are absolutely right, all you have to do is chase these circuits down with a voltmeter and you WILL find the problem.

Your turn signal relay diagram is amazing, but for the user, the simplified version of the story is that the flasher unit (relay!) is powered when you turn on the ignition, and that (and this is the really important part) the CDI, headlights, horn, and the STARTER button, are also lit up when you turn on the ignition.

The gear position indicator is a whole different story. It relies on the head unit (speedo assembly), and the 6x connector from the gear position indicator sender. It is remarkably simple in design (grounding changes). Patience and a multimeter reveals all...