Bike not cranking-check my thinking

[MAC10]

My 78 gs1000 won't crank.
Last season I put in a new stator, and that is when this began. I removed the stator cover and rechecked assembly, thinking the starter clutch was jammed-I am sure it is not. I think the new stator is coincidental.

Here are the measurements
Battery is new last season, kept on trickle charger over the winter.

Across the battery terminals-12.25 volts
Across the starter solenoid-12.25 volts
From the starter button to solenoid- 11.03 volts

Bridging the solenoid, starter button on or off, does nothing. Solenoid does not click. Original starter motor.

I am electrically green. What is happening here?

 

[Guest]

Find your wiring diagram in one of these 1K service manuals from Cliff's site - always good to have a map in case you get confused...

http://members.dslextreme.com/users/bikecliff/

Find the hot wire and use your multi-meter to trace it to the point it goes dead. I know that kill switch/starter button handlebar control is the source of many dead bikes. Take it apart & clean everything well, make sure the contacts are bright & shiny, and put it back together with some dielectric grease.

Be mindful when you take it apart though - several small bits & things can easily pass into the great unknown, never to be seen again. Pay attention to how its assembled as you take it apart - those little screws that hold the stays and brackets are all different lengths and go to specific holes... it ain't rocket surgery, just take a good look before ripping it apart.

Tip - When I'm chasing electrical stuff, I pull the headlight fuse to kill that big drain on the battery while I have the key on.

 

[Big T]

If your solenoid doesn't click, it's stuck

pull it from the panel and gently remove the screws holding the top on pull the top up a bit, Do this carefully so you don't break the internal wire. Spray some contact cleaner in there and allow to dry. Reassemble. Remount

Test the battery voltage with the starter button pushed and tell us what that is

Take the starter cover off and measure the voltage at the starter terminal

If you're getting about 12V at the starter terminal and no starter spin, pull out the starter and take it apart

 

[tom203]

"Bridging the solenoid, " jumping the big terminals? this bypasses solenoid, so if starter doesn't turn, then problem lies with connections to starter or starter itself.

 

[barnbiketom]

Does your headlight light up properly?? if not then you batt is crap or dead.

does the solenoid 'click" when you press the starter button?
if not there is a problem there..either with button/wiring/battery..

THEN if you 'bridge' the two BIG terminals and nothing happens, THAT IS ANOTHER PROBLEM.. the starter should engage.

Try checking the BATTERY VOLTAGE while pressing the starter button.. it should remain close to battery voltage.

 

[AJ]

"Bridging the solenoid, " jumping the big terminals? this bypasses solenoid, so if starter doesn't turn, then problem lies with connections to starter or starter itself.

Agree with Tom above.

In addition, 12.25V at the battery terminals indicates that battery is not charged. A lead acid battery should be at 12.6 V when fully charged. Still, s battery showing 12.25V should click the solenoid and make the starter motor umphh, even if it won't crank the engine.

 

[bmuscoty3790]

Check you "starter disconnect switch" which is right under the clutch handle. It should have two black wires with stripes going to it. I took mine apart and it was not getting a good connection. If that is the issue...you can bypass this switch if you are brave enough to ensure you have it in neutral every time.

 

[MAC10]

Thanks everyone. I left the bike on the charger until I had time. Across the battery terminals I had 13.5 volts after charging.

I replaced the solenoid, and with the new one am now getting the bike to crank using the screwdriver across the posts method. I am only getting 11.25 volts from the start button to the solenoid, not enough to get it to work. Somewhere I am losing 1.5 volts. Next task is to trace the wiring to find the fault. Should this kind of voltage loss be enough to stop the solenoid from working?

I have inspected and cleaned the handle bar kill switch and start button. They look good. This bike doesn't have a clutch switch.

Good news is the starter itself works fine.

 

[ThrottleBack]

FYI i was fixing a no crank issue on my 81 GS450TX today. In doing so I noted that my power from starter button 11.00-11.25 so i'm in your range. My point being a new solenoid fixed mine so your 11.25 should be plenty for the starter button to function because it is for me. I suspect this range is "normal" given the age of the machine. Also if you have power from the starter switch the kill is working.

I suspect the issue is the ground for the solenoid.

 

[MAC10]

Thanks Throttleback,

How does the solenoid ground? I have it bolted to the electrical panel/frame on an alumuminum plate to drop it a bit to fit an aftermarket RR. The solenoid I have is the type with the single wire going to the switch, just like the original. I thought it grounded throught the body.

 

[ThrottleBack]

I'm no expert in fact i'm extremely green i just happen to have gone through this. my factory one appeared to ground through the plate it bolts too and I have the same setup you do. My new one is a solenoid from a mower that grounds when bolted up to the factory location, which supports my theory.

You can use a jumper cable or a wire to run a temp ground from the solenoid body to the frame. If it functions you know the ground is your problem.

 

[MAC10]

Thanks Throttleback-I'll try that. I am working hard to get knowledgable about the electrical stuff-my weak point.

 

[ThrottleBack]

It's mine too. I "get" most of it but I almost never have the ability to properly use my voltmeter. It's a mission to rectify that as many roadside issues are electrical.

I got the jumper cable trick from my dad long ago testing Jeep issues in the woods.

 

[MAC10]

Cranking issue solved

Cranking issue solved

I added a ground wire from the solenoid mounting bolt to the battery negative. Problem solved.

The new solenoid switch I used has a plastic body, and would not ground as it was. I had to add a mounting plate to lower it half and inch to fit the new Shindengen SH775BA RR I added. I also had to cut the fin a bit between the solenoid posts, and shorten the positive solenoid post to make room.

I noticed on my 78 GS1000C, the stock plate on which the rr, solenoid, fuse box and flasher all mount, has rubber grommets between the plate and frame.( I guess to stop vibration?) That means grounds must go to the battery or the frame, not the stock mounting plate, to be reliable. I have added a short ground wire from a leftover tab that used to hold the separate regulator, to the frame, just in case.

Thanks to everyone for your help. I am learning fast.

 

[ThrottleBack]

I'm glad I had it pegged, going through this gave me some insight to my bike and i'm glad to have suffered it. some advice i got that I love. Make a couple ground wires with loop connectors:

R/R to Solenoid bolt
Solenoid bolt to frame by battery
Frame to Battery -
Engine Block to battery -

Also worth taking the time to make all the old butt connector new spades. All this took me three hours with one hand.

 

[MAC10]

I am going to add grounds as you suggest. Seems a simple fix, and a good precaution. Thanks for the help.

The next task is to ensure the new rr is charging correctly, and then to install a dyna s electronic ignition. Then , time to ride the thing and stop working on it so much, touch wood.

 

[ThrottleBack]

NP. if you open my thread a few down from this one there are pictures posted by the member who filled me in