Topic: Please Help Identify This Fuse???

[no718.com]

Having electrical issues. I tested the main/tail light/headlight fuse with multi-meter and all are good. Starter won't turn over.

Tested this fuse and there is no continuity must be blown. Is this the starter/solenoid fuse? Where can I buy a new one? How many amps is it? Any help would be appreciated. Thanks all.

[scottly]

That's not a fuse, it's diode; see the "arrow" symbol?

[no718.com]

Forgive my lack of knowledge . . . I pretty much know nothing about electrical. What's a diode? Should it have continuity? Do diodes blow? did I test it right?

[scottly]

Will the starter turn when you pull in the clutch lever?

[no718.com]

Nope. I get nothing. I was getting a click when I'd push the start button but now nothing.

[scottly]

OK, how about a little history. First of all, what bike do you have? K8? Did it work at one time?

[333]

A diode should have continuity in one direction only.  Check it one way, and then reverse the tester leads.

[TwoTired]

A diode should have continuity in one direction only.  Check it one way, and then reverse the tester leads.

That's correct.  But you have to use a meter capable of checking diodes.  An an old analog type or a digital type with the diode symbol on the scale selector.

However, if the bike is in neutral, the starter should engage regardless of clutch position.  The diode just keeps the neutral light from coming on when the clutch is pulled in.

[scottly]

A diode should have continuity in one direction only.  Check it one way, and then reverse the tester leads.

That's correct.  But you have to use a meter capable of checking diodes.  An an old analog type or a digital type with the diode symbol on the scale selector.

However, if the bike is in neutral, the starter should engage regardless of clutch position.  The diode just keeps the neutral light from coming on when the clutch is pulled in.

The ground from the neutral switch is supplied via the diode to the solenoid, whereas the ground from the clutch switch goes directly to the solenoid. If it won't crank with either the clutch lever in, or the trans in neutral, then I would suspect that 12V is not being supplied to the other end of the solenoid coil via the start sw, or the solenoid itself. Of course, this assumes a fully charged, good battery, but without any history, it's all we have to work with for now.   

[Spanner 1]

And the bike is??.... and describe your fuse testing, por favor... ?

[no718.com]

So sorry guys. Its a 1978 750K. I do have a fully charged battery and the bike is in neutral. Also the bike was running great a few days ago fired up like a champ, until I took apart the front end to install clipons.

I am using a digital multimeter which can test for diodes according the instructions manual.

[scottly]

Just put the diode back in, you have something wired wrong in the handle bar controls!!!!

[no718.com]

As for testing I just put the multimeter on the continuity setting and touched the probes to each tooth on the diode . . . I'm guessing thats not right? Another thing I failed t o mention is that I literally cut the wires to my front blinkers because I was going to install new ones, never did, and just tucked them into the headlight. Could that have shorted something out???

Again, my first bike, please bare with me.

[Spanner 1]

O.K. then... with ign. 'on' all black wires should be + 12v ( or whatever battery voltage is ).... yes?, no?... does the h/l come on with the switch ?...

[no718.com]

Yes, with ign 'on' the headlight comes on bright and dims every time I press the start button and yes kill switch is on as well. also neutral light and oil light are on.

[Spanner 1]

O.K.... the 'N' light comes on and the h/l comes on but dims when the srart button is pressed... then either the battery is bad or the starter motor is 'stuck' or seized..... a good battery should spin the starter no problem, pretty fast.

[no718.com]

Hmmm . . . I have a brand new battery in it and its fully charged. So if it is the starter motor being seized or stuck what would next steps be?

[scottly]

Go back to the last thing you changed before the problem started: the handle bars and wiring up front!

[Spanner 1]

I'd do this... undo the 2 bolts on the starter cover, remove and then undo the 2 starter bolts ( backend  of the starter ) and remove it. Is it free to turn?... prolly just needs to be freed-up by hand.... work the start button lots to spin it.... re-install.... good, yes/no ?? OR the start solenoid contacts are ' blackened' and not able to pass the current to spin the starter..... search for 'solenoid' , info on take apart and fix.....

[scottly]

The started worked before he messed with the switch wiring. The headlight is dimming because the starter switch shuts it off when depressed. At least, that's my best guess.

[Spanner 1]

He never said the starter worked at all....!!! ( different thread !).... has to be solenoid or start motor,,, more likely solenoid... poster needs to 'read-up' on solenoids, yes?... info is on this Forum.

[no718.com]

Yeah prior to disassembling front end she fired up like a champ no issues. I'll have to look at the solenoid/starter tomorrow.

[scottly]

He never said the starter worked at all....!!!

So sorry guys. Its a 1978 750K. I do have a fully charged battery and the bike is in neutral. Also the bike was running great a few days ago fired up like a champ, until I took apart the front end to install clipons.

I am using a digital multimeter which can test for diodes according the instructions manual.

[Spanner 1]

My bad..... yep serious voltage drop when start button pressed, moden litely.... diode thingy is co-neccted across the clutch switch so as the starter wont engage with the bike in gear ( in gear and clutch pulled = O.K. for start )... Diode is programmed with intelligence to pass voltage only when clutch is pulled or bike is in 'N', or both...



Just kidding about the 'programmed' thing....

[scottly]

Spanner, I know you know what you're talking about. You have taught me a thing or two. You just missed a slight detail on this one.