Bad solenoid, starter relay or something else?

Hi Guys,
I'm continuing to peck away at getting my recently acquired '86 VF500 F running and have run into an odd problem. After installing a new, fully charged battery, a $13.00 E Bay solenoid (with an attached relay) and removing all the spark plugs to do a compression test, I hit the starter button and the engine spun over very quickly. "Cool eh, my starter system is working!" , well cool except for the fact that when I released the starter button the starter kept on spinning, cranking the motor over rapidly because of no plugs being in it. So, I turn off the ignition switch. Yikes, it kept cranking until I quickly disconnected the battery. Once my breathing was back to normal, I set up a quick disconnect for the battery ground and tried to crank it again. Nothing happened, no click no crank, nothing except that when I hit the starter button the lights dim. Emboldened, I fully reconnected the main battery ground cable and tried again. Again , nothing except dimming of the headlight when hitting the start button.
Tomorrow I plan to see if it will crank when I very briefly connect the thick copper posts on the solenoid with a heavy jumper cable, but I'm not sure what it cranking or not cranking would tell me about my problem.
My intuition says the continuous cranking was because the components that handle the heavy current inside the solenoid were not breaking the circuit as they should, and that I'm getting nothing now because any solenoid that sells for $13.00 can be expected to fail with less than a minutes use. But basically I'm stumped.
So, what do you suggest I try next to identify and correct the problem?
Thanks in advance,
Jay

 

I am not familiar with an '86 what so ever But.... I would hook everything up as it should be. Turn key on, make sure kill switch is on, hit start button. If it doesn't crank then you need a meter to test to see if you get 12volts to the smaller wire at the solenoid. If you don't have power there then you need to work your way back to the start button and kill switch to see where you are losing power. If you have power there then see if you have power on the big wire going to the starter, if you have power at the smaller wire but don't have power going to the starter wire then the solenoid is bad. If you have power going to the starter but it doesn't crank then the starter is bad or in small cases the solenoid will allow voltage to go thru but not in enough amperage to turn the starter but you can jumper the two large terminals to see if it's bad contacts in solenoid. When the bike kept cranking, it sounds like either the start button got stuck or the solenoid contacts stuck together.

 

Skip the short test. Hold the start switch in and tap on the starter motor with a wooden hammer (hammer handles work great) first. Just a few quick taps. Not hard but not soft either. Then tap on the starter relay(solenoid is just another name for relay in automotive speak) and check that your start switch is sending power to the start relay.

what the tap test tells you is if you have a stuck contact. Solenoid relays pull an armature in to the center, a contact disk is attached to the armature and this contacts two poles and bridges them. This can get arc welded to a pole and hold the solenoid in, when you disconnect the power it relaxes a bit and jams. If you need to prove the starter motor use jumper cables and run from positive battery pole to the motor positive lead. The motor should turn as soon as power is given. If it doesnt, a brush inside could be stuck, worn out or worse a winding is blown.

Be methodical, start from the starter motor and use a multi meter to check for voltage at every point in the circuit you are tracing. You have two, the high current circuit from battery to solenoid to motor. And a control circuit: batter, keyswitch, kill switch, start button and solenoid control connection. Solenoid must have its ground attached to frame to work correctly. Also check fuses, everything has a fuse, make sure it hasnt blown. Starter motor fuse should be 30 to 60 amps. Never replace with a higher fuse for any reason. Always use the fuse as per the owners manual (if you dont have one im sure someone on here does.

If you let the smoke out of electronics and electrical then it wont work anymore.

 

+1^ on what Zen says, except that there is no fuse--power goes thru a big fat red wire from the battery positive to the starter relay to the starter motor, and the return is thru the engine case into the big fat black wire to the battery negative.

From what you described the starter relay contacts welded closed and could not release. The starter button sheds the headlight load to put all the energy into the start function--that is why the lights dimmed and is normal.

Probably need a different starter relay--wouldn't want to trust that one.

 

Different years have different fusing policy. If you want to make the mod, pico makes a great 50a and 100a starter breaker. Pops and is push button reset. If you cant get one pm me. Last thing you want is a 8awg wire and no protection going to frame! If you want to measure the current to the motor, you will need a 0.01ohm 500w resistor in series with the motor, then measure the voltage across the resistor and that will be amps after a little calculation. To give you an idea of how many amps it should draw, my 07 vfr uses a 60a fuse for the starter motor.

 

I've seen cases where the START pushbutton was sticky and wouldn'
t return to its OFF position due to dirt or a weak return spring.

 

Thanks for all the help Guys,
The exact cause of the problem with the continuous cranking remains a mystery but seems to be fixed at least for now. I cleaned up all the connections, removed and cleaned up the starter button and the starter is working perfectly now. Now that I can crank it over fine, I'll be moving on to the next problem, which is no spark on the front 2 cylinders...
Jay

 

Post details. Also make sure you have power to the coils. Everything is backwards from common understanding. We remove the power to make the spark.

 

That's SO Zen !!

 

Would you have him test and say its fine only to discover that the power never goes away? If you have an understanding of how the system actually works and what to measure for then diagnostics can be as short and sweet and you will have an answer to the issue. 99% of the time its something stupidly simple that screws up and kills the system. That last 1% we reserve for the modder who doesnt know enough but is dangerous.