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starter slow to spin

Discussion in 'The Garage' started by maia 8cars, Jun 15, 2015.

  1. Since I got my bike the starter has never seemed to want to spin fast enough to fire up the motor but it starts right away with the kicker. Put a meter on the starter terminal and ground and pushed the button. Meter read 7.5 volts. Is that normal? Is that just the starter draw dropping the voltage or is there something haywire here. Thanks in advance. '78 xs 15000 km on the clock, new rings cam chain, valve grind, runs great, charges to spec.
  2. Brassneck

    Brassneck XS650 Guru

    When you say you tested at the starter terminal, do you mean at the starter relay, the starter motor, or at the switch on the bars?

    A slow turning starter could be a few things...here's what I'd look at:

    1) weak power-- check you battery, if fully powered, then test it at the relay, there are two main wires (large black ones with boots)...one comes from your battery (the one on the left, should be able to follow it directly to your positive side on the battery), when you press the button, the relay sends power to the other one (on the right) and down to the starter motor. when you press the button, you should have 12+ volts going to the starter motor. If not, then you will need to see why you're dropping power between the switch/relay, etc.

    2) bad grounds... check all the grounds/connections (the starter motor mounts are it's ground).

    3) Bad starter motor...they do need to be cleaned from time to time. polished/new brushes, etc. Also, the oil seal can leak and oil gets into the starter motor...over time, this will make the motor spin slower and slower and ultimately stop working (I just literally had this happen to mine. I pulled it out, swapped for another from a member on this board and it works great now. The old one I took apart and poured all the oil out of it...cleaned it up, and works great!

    Test the starter motor...Make sure the bike is in nuetral and then simply get a jumper wire from the positive terminal (on a fully charged battery) and touch it to the starter motor terminal (Under the bike..it has a boot on it, and is the only cable going to the starter motor). If the motor is good, it will spin like crazy and then you'll know it isn't the issue. If it spins slowly, it's gonna need to be cleaned.

    Hope one of these helps.
  3. XSLeo

    XSLeo XS650 Guru Top Contributor

    I have a spare car battery that I use for testing things like this.
    If you don't have a spare battery you can use your car battery, just get it close enough to reach the bike with jumper cables. If you use your car DON'T start it. The car alternator has too high an output.
    Now on to the testing. Leave the bike shut off and in neutral. Peal back the rubber boots back to expose the cable lugs on all the starter cable ends.
    Now hook the jumper cables to the battery. Hook the black clamp to a good ground on the bike. I use one of the foot peg mount nuts. In the red clamp put a big screwdriver, Use the screwdriver as a probe. Touch the screwdriver to the cable lug on the starter.
    This should spin the starter and crank the engine. If not then the starter needs work.
    Now move up to the starter relay, touch the screwdriver to the cable lug the cable to the starter hooks too. It should spin the starter as well as touching the lug at the starter. If not the connections on the cable are in need of attention. Clean them up.
    If everything works well so far, then the starter and cable is ok. Now to test the other cable.
    Take the screwdriver out of the red clamp and hook it to the positive on the battery. Now turn the bike on and try starting. If it starts ok then your cables are ok. I would take the cable off at the starter relay and clean it anyway. Same at the battery.
    This checks out the positive side of the circuit. The negative or ground side may still be weak. The starter grounds through the body of the starter to the engine case. The engine case to the frame, frame to negative cable, to battery.
    Pulling the starter to clean that connection can be a bit of work. The rest is easy. At the rear top of the engine case is an engine mount. It has two triangle shaped steel plates that bolt through the frame and engine case.
    Take this mount off, clean the mounts where the touch the frame and engine. Clean the places on the frame and engine the mount touches. Clean means bare metal to bare metal. Reassemble with a thin coat of grease to prevent corrosion.
    This will improve the ground from engine too frame. Do at least this mount. I also do the top mount and front mount. The top mount is more involved, it has 6 pieces as well as many bolts to clean up.
    Now at the frame where the negative cable bolts on you need to remove it and clean there. This will improve the ground half of the starter circuit.
    Cleaning the battery cable to frame connection will help with the rest of the electrical grounds.
  4. Great advice as usual, thanks a lot guys. I'm going at tomorrow will let you know what I find out.
  5. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    No, that is not normal. You may have a bad cable or corrosion on the battery + cable, and/or the same thing on the cable from the starter relay to the starter motor.

    However, I suspect the real cause is your battery is very weak, and cannot deliver the full 75 to 100 amps needed to turn the starter motor. Its considered normal if the voltage drops to 10 volts or more.................that means a healthy battery. 7.5 volts means the battery has failed a load test, and is probably dead. You can try to charge the battery, but I see a new battery in your future.

    What type of battery is it, and how old is it?

    Edit: Measure the voltage at the battery positive terminal as you push the start button to crank the engine. If the voltage drops to 7.5 volts, then that eliminates any cable/connection problems, and means the battery is dying/dead.
    Last edited: Jun 15, 2015
  6. Ziplockbaggie

    Ziplockbaggie XS650 Member

    Thought I would resurrect this thread on Easter. No pun intended. Bike is extremely sluggish to turn over, then finally no turning at all. So I've been through the usual items. Brand new battery, new hot cable from the starter solenoid. When I hit the electric starter, all I get is a click from the starter solenoid region. Is this the failure mode for the solenoid?
  7. Brassneck

    Brassneck XS650 Guru

    Click is normal...get a jumper from the positive terminal of the battery to the starter motor's positive terminal (under the bike)...see if it spins. If it doesn't spin hard, it's the starter itself that's the problem...otherwise, may be the starter switch...or a ground, etc.
    Last edited: Mar 28, 2016
  8. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    Brand new battery means nothing. It could be defective. Some batteries need to be charged for approximately 10 hours before they can be used, while other batteries come fully charged.................which type did you buy?

    Here's a simple test. Connect your digital VOM meter to read voltage from the battery + and - terminals. Watch the meter as you push the start push button, and crank the engine. If the voltage drops to below 10 volts, your battery is very weak and likely needs to be replaced (you could try re-charging it). If the voltage stays up around 12 volts, then there is a problem with cable connections, ground cable, starter solenoid, and maybe the starter motor itself.
  9. XSLeo

    XSLeo XS650 Guru Top Contributor

    See post three.
  10. Brew

    Brew XS650 Addict

    Mine did the same thing. I removed it, opened it up and cleaned the inside with some purple power. Put it back together. re-installed it and BOOM, starter works perfectly. There was a lot of oil residue in there I guess creating the problem.

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