Starter Motor.

[Tango]

Ok my bike needs the starter motor looking at.

If you press the start button sometimes it spins …Sometimes Nothing happens at all.

It never turns the motor over but I think it needs a new roller kit?

What else should I look for?

This is what is behind the cover.

[Michael]

Hi Tango,

first you have to find out if there is a failure in the electric starter circuit (switch, relais, motor) or the “one way” clutch itself. Maybe both things are not working properly?

You may do a test of the electric start in that condition as your photo shows it. That’s a good possibility to check what happens when you push the “Start” button.
Pay attention to turn of the motor immediately if it fires up !
… or you may remove the spark plugs before 😉

Here you can see how to repair the starter clutch:
http://www.z750twin.de/anlasserfreilauf.htm
Google Chrome will offer you the translation option 😉

After the starter clutch is swapped it is very important to get the LH screw fixed very firmly and Loctite (medium) has to be used.

I use a pneumatic screwdriver (as known from professional car tire changing stations)/ air-hydraulic impact wrench.
My compressor has 6 bar air pressure and I turn the screw in until the tool doesn’t fix it any firmer. No idea what the torque is in the end 🙁

You will need a new gasket for the alternator cover as well.

Maybe KK can help you. He has some experience with that and probably the right tools :-)))

Cheers, Michael

[dougyt]

On My Twin firstly the starter was spinning internally as it wasn’t clamping the outer gear part. Then I had a dodgy solenoid. As Michael said look at the electrics first and ensure the voltage is getting to the starter.

[Tango]

Sorry I did mean that when you push the start it sometimes spins the starter motor but not always?. But it never turns the engine over.

[dougyt]

If it only sometimes spins the starter then the solenoid or main cabling may need attention. It also could be brush gear in the motor. If the motor spins but the engine isn’t turning then it could be inside the starter motor the gear race is spinning. I stopped mine spinning with a little packing to clamp it tighter between the two ends of the motor.

[Michael]

Hi Tango,

sounds like you are facing at least two issues.

Issue 1: As dougyt said, check if electrical power comes down to the starter motor.
Possible errors are bad contact in the starter switch (at handlebar) itself.
Maybe the starter relais (solenoid?) is not working correctly or the small cables from starter switch to relais are in bad condition.
Finally the contacts / coals inside the starter motor are worn and need replacement.
Just as an example:
Starter KIT Kawasaki Motorcycle KZ750 KZ 750 76-83
http://www.ebay.de/itm/270516508179?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_1432wt_1192

Issue 2: If the starter motor turns but can’t turn the motor it is very likely that the one-way-clutch is defective and needs replacement as described before. You can see in the picture a small gear inside the motor. I understand that dougyt had trouble with that.

If you plan to disassamble the starter motor, first disconnect the battery !!!
Please be very careful when removing the nut that holds the “power cable”. The bolt that sits at the side in the motor must be hindered to turn. If it turns with the nut, stop immediately and think about a mean to hold it in position. If that bolt turns, the small cable inside the motor will be damaged (ruptured?) and that is hard to repair.

Cheers, Michael

[Michael]

Tango,

there is a simple trick you can use to test at least the starter motor and if it turns, especially with the alternator cover removed.

This trick is some kind of dangerous, so don’t do it if you are not sure what you are doing !!!

The starter relay has two M6 bolts with the large power cables connected to it. Both are PLUS. One is connected to the plus of the battery, the other cable goes down to the starter motor. You may use a large ring spanner and push it firmly onto the two bolts. As long as you are contacting both pins the starter motor should turn immediately !

ATTENTION: Please cover any other metal pieces around that area, especially the frame, with tape, clean clothes, etc. to avoid any contact of the spanner to the frame. That would be a heavy short circuit of the battery and there is no fuse in between !!!
RISK OF FIRE !!!

ATTENTION: For sure there will be some sparks when the spanner hits the bolts. You must be determined to press the spanner firmly to the bolts and hold it there. Do not reduce the pressure until you remove the spanner completely.

You should do this test with the ignition switch in OFF position.
That ensures that the Twin-motor will not start.

Cheers, Michael

[Kaptainkwak]

You are exactly right there Michael and so are you Dougyt. I am in discussion with Tango about these 2 issues. He is wanting to understand this himself so it is difficult for me to discuss and not fix the problem which is why he is asking on here.

Thank you guys and please keep the help and advice coming.

[Michael]

I appreciate that Tango wants to understand the things 😉

It is not always needed to learn from own failures, one can learn from other’s failures as well ;-)))

It is a learning curve !

I have shown my son some of the things related to bikes and he now knows what to do with spark plugs, carbs and some things more 🙂

Keep it going !

Cheers, Michael

[Tango]

It’s no fun trying to learn this stuff Blind.

Its so much nicer being part of a specific Family and getting a helping hand from those who have earned the knowledge and sometimes it was earned the hard way!

I will take experience over expense any day!

Thanks for your Help Guys.

The other side of it is, I’m a self confessed Newby at all of this! And there is no such thing as a stupid question if you don’t know the answer!

So I just hope all my questions on the problems I run into, Are common problems and I hope that the Questions and Answers are for other New Members coming across the same things as me.

[Michael]

Hi Tango,

there are no stupid questions existing, only answers may be stupid !

(Tried to translate a german saying)

Go on and ask your questions 😉
I highly appreciate it.

Cheers, Michael

[Kaptainkwak]

That is a great statement Michael.

Tango you are correct to ask anything you wish and if anyone bullies you tell me and we’ll get em

[Tango]

LoL

I dont think I have a problem with being bullied

I may get a few cheeky comments now and then! But thats only to be expected! Ha Ha 🙂

[Michael]

The ordered M18x1.5, 50mm long, 8.8 quality screws arrived.
Will give them a test this weekend and post if that is the matching thread size for use as rotor puller.
Michael

[Kaptainkwak]

Thank You Michael. Sorry I have not had a chance to check it out yet what with my contract ending and everything else that has been going on. Can you also make a judgement on a 40 long screw as well please. I will work with your findings here.

Cheers buddy

[Author]

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