Ok fellas, i'm in need of serious help! This is a tough one!

[intrigue175]

Ok here's the problem. I have racked my brain trying to solve this one.

It's a 79 GS425 with roughly 20k on the clock. Upgrades include but are not limited to: Dyna pointless ignition off a GS400 (yes it works perfectly), Dyna coils with coil relay trick, new starter solenoid, new rebuilt starter, newish reg/rec. Those are all the upgrades that matter for the problem.

Now the problem is it won't turn over using the starter button. At the most it barely cranks a 1/4 turn. Here's what i have done so far to trouble shoot: Rebuilt original starter and bench tested as good using a charger set on 2 amps, replaced starter with rebuilt one off ebay also bench tested good at 2 amp setting, replaced solenoid, cleaned all connections between starter/switch/battery and grounds. Have completely bypassed starter switch and solenoid by testing with charger straight to starter positive and grounding on starter directly. No change. Have tested voltage from starter positive (disconnected) to battery negative with less then a .5 drop. Have pulled starter clutch checked and cleaned bearings. No change. (is flywheel only supposed to spin to the right (clockwise)?) Have changed batteries with a known good one that holds 13+ volts all day. Inspected starter gear to see for binding (looks and feels free) Have done a compression test cold (testing maybe internal binding or drag) 150-155, well with-in specs. Used kick start to see if i could feel motor binding up in some way. Feels same as always has.

Bike runs beautifully with kick start, just not starter button. Yes i know just use the kick and ride it... However i am selling it and most people are a bit intimidated by using a kick. Plus it is a smaller bike and more then likely will be sold to a woman or smaller person then i (6'2" 220). So kicking can be very scary to new riders that can barely balance the bike with 2 feet.

Guys i'm really out of ideas and need the communities help here. I tried to list every test i have done and am still at a loss. ANY help is greatly appreciated!!!

Thanks in advance.
Charlie

[tatu]

Are all the earth wires in place? Big heavy one to the engine from the battery, good clean contacts?

[intrigue175]

Yes, i also completely bypassed the electrical on the bike just to be sure by giving power and ground directly to the starter with it in the bike and with the bike positive disconnected just in case the solenoid was shorting.

[tatu]

If you can kick it and away it goes then your problem is not a stiff engine, it has to go back to the starter circuit, you say the starter worked on the bench, was that under working load? I'm only guessing here but a 2a draw doesn't seem much for a starter under load.

[tatu]

The test would be is to run a heavy earth direct to the motor from the battery and another direct to the motor side of the solenoid that should spin the motor, if not its likely a lazy starter.

[intrigue175]

Ill try that, but keep in mind i have tried the starter i took apart and cleaned up and the new refurbished one off ebay. The bench test was not under load. It was just a spin test. I have also tested the starters in the bike straight from the battery while adding a ground directly from the starter case. No change.

[oldrookie]

Sure the starter switch is not grounding out between the handle and the case?

[barnbiketom]

using a charger is NOT LIKE a GOOD battery.

I suspect, with all you have done, is that you have two batteries ( you did try 2) that are bad.
batteries can provide 12 to 14 volts and still not have enough AMPERAGE to be useable.

a LOAD test will prove this,

BUT

Try jumping the starter in the bike, with a car that is not running. black to engine ground and red to the terminal on the solenoid that Goes to the starter.
If the starter works, then your batteries are gone.
I'm not saying there's nothing else wrong in your start button/wiring or elsewhere, you just need to get the starter to turn on it's own first to crank the bike then work the other way back...

[nejeff]

using a charger is NOT LIKE a GOOD battery.

I suspect, with all you have done, is that you have two batteries ( you did try 2) that are bad.
batteries can provide 12 to 14 volts and still not have enough AMPERAGE to be useable.

a LOAD test will prove this,

BUT

Try jumping the starter in the bike, with a car that is not running. black to engine ground and red to the terminal on the solenoid that Goes to the starter.
If the starter works, then your batteries are gone.
I'm not saying there's nothing else wrong in your start button/wiring or elsewhere, you just need to get the starter to turn on it's own first to crank the bike then work the other way back...

Do this, its good advice. This is the obvious way to narrow it down fast

[GreaseMonkey]

Do this, its good advice. This is the obvious way to narrow it down fast

+1 Use a good, fully charged battery and test them on the bike. I don't have a lot of experience with bikes, but I have seen TONS of automotive starters that passed a bench test but didn't have good enough contact on the brushes to actually spin the engine under load.

[pete]

Also, you can try hitting the starter with the spark plugs removed to release the compression a bit.

Better to try with a known good battery but this may help as well.