No power to starter motor

I've been having this issue for awhile. 1982 GPz750. I press the starter button and nothing happens. No clicks, no dimming of the lights, and nothing gets to the starter motor.

I have a full charge on the battery. My wiring from the button, to the battery, to the starter relay, to the starter motor is all sound. In fact, I even got a new starter button and complete new wiring harness.

The weirdest thing about this is, when bridging the posts on my starter relay, the battery will start to hiss and all my lights will shut off.

I placed an ohm meter on the starter relay and, depending on polarity, it would read either -132.7, or -1.

What should my next step be?

Sounds like the battery cable from the solenoid to the positive terminal on battery is losing contact at times. Remove and clean the battery cable from battery to solenoid. You can carefully use a razor knife to scrape and scuff the terminals and check for green corrosion on terminals and clean in baking soda water it, it will safely remove the acid corrosion on the cable (while off the bike of course) do not clean while installed.

How old is the battery?Maybe have it load tested

kzoldschooler wrote: Sounds like the battery cable from the solenoid to the positive terminal on battery is losing contact at times.

My contacts are solid, freshly cleaned an hour ago. Still nothing. I have 0.3ohm reading from the positive contact to the solenoid.

This battery is fresh. Load and voltage tested and it's also solid.

When my bike had about 35,000 miles on it, it got to a point where the starter would not crank. Everything up to the starter was proper. I took the starter itself off; dismantled the starter, and found that 2 of the 4 brushes were worn completely away. The bike had been weakly starting only by the copper wire touching the armature. Not cool. Replaced the brushes and all is well.

Check your - to frame connection thenmaybe use a jump lead from the + direct to starter motor terminal and see if it cranks, then you can narrow it it down to starter motor brushes.

Starters on these seem to last for ever, dismantling them is an easy and quite an interesting job. The brushes are spring loaded and have quite a lot of'meat' on them.

Tyrell Corp wrote: Check your - to frame connection

Where does this connection happen?

sorry I meant: Battery - ve terminal to earth point on engine, rear top end of cranckcase just behind clutch casing. It is good to remove this and clean it up anyway,

Tyrell Corp wrote: sorry I meant: Battery - ve terminal to earth point on engine, rear top end of cranckcase just behind clutch casing. It is good to remove this and clean it up anyway,

I just did this. I also just connected a jumper cable to the positive post of the battery and touched it to the post of the starter motor. I got the same thing again; lights went off and the negative battery terminal started smoking.

Now, I have the starter motor removed and, testing it again with the jumper cables, it functions very smoothly. I replaced the brushes like two months ago, so they're good (I think.. unless they've gone bad already).

If your negative terminal is smoking when you do that You have a short somewhere, especially considering removal from the bike it operates smoothly
What was the last thing you removed/ replaced/ modified?

Although I will test a starter with jump leads it is only a one second burst: the starters are very high tourque but not designed to run fast on no-load, so careful here.

What if you refit, then power up the starter,with jumpers from B- to motor earthpoint and B+ direct to starter terminal, other battery terminals disconnected -does it crank?

If No, assuming your battery and jumpers are good then I guess it is a starter motor problem that new brushes 2 months ago hasn't fixed...maybe cleaning up the commutator is needed. There is a procedure in the Haynes manual using an old hacksaw blade to 'undercut' the segments, Do not use aluminiium oxide or emery paper on it, and solvent clean the commutator afterwards carefully. The commutator grooves can get filled with carbon dust from the brushes, and any abrasive paper residue which acts as a conductor where it shouldn't.

if yes and it cranks ok, but problem persists when battery terminals are re-connected then your fault lies somewhere within the wiring to it.

Re-chcek the starter fitted with the jump leads only: what could be drawing far too high a current when trying to turn the engine might seem to work fine on the bench with no load.

From reading your posts, it appears everything has checked out fine, even the starter. So what does that leave?
How about the motor? are you sure that it's not locked up? Or maybe when you tighten the starter bolts something binds the starter gear?

Take the plugs out, put in in first gear, and see if you can bump the engine over by turning the rear tire. It's probably going to be hard to do, you may have to keep bumping it hard to get it to move. If it moves, then I'd take a hard look at everything between the starter and the secondary shaft.