Kawasaki G3SS Wont Kick Start

[Milan]

Headed up to Barbers this past week.
Picked up a little 90 cc Kaw.

Owner then told me it runs if you bump start it in first, but will not start by kicking.
Runs fine after bump start. Shut it off, will not kick start

He said others told him it may be the points.

Took carb apart & cleaned. Put back in same thing.

Any thoughts of where else to start?

M

[m in sc]

if it runs bump-starting, it isn't the points. does the Kickstarter spin the motor after warm or is it slipping?

you didn't buy that yellow 71 for 3 k did you?

[scully]

more than likely a mag coil, kicker can't spin it fast enough to create voltage.

[Milan]

Kickstarter spins motor fine.

I was able to start it a couple times with the kick starter.
Bike came with a NOS flywheel & points plate with the coils.
Getting a puller & going to put that on & see.

Hard to believe the mag coil would be bad, bike has less that 2K on it.
Must have been an ongoing problem with the bike tho, as it also came with a used ignition coil, and a used ignition switch, and some points

I did not get the yellow bike.

[m in sc]

yeah, good point.. (pun intended).

that ign winding can get weak.

fyi, early kh100/ke100 stuff swaps right in.

https://www.ebay.com/itm/325109223902?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=dH0rbNM2RSO&sssrc=2047675&ssuid=9DXeqLNdSLW&widget_ver=artemis&media=COPY

[Milan]

https://www.partzilla.com/catalog/kawasaki/motorcycle/1972/g3ss-b/ignition-generator-74-75

Mine has the 3 coils on it.

In the diagram the bike came with parts 6 & 7.

M

[m in sc]

it varied from year to year. only 1 winding is for the ignition. . also ,make sure the coil wire is ok, cap, etc.  Mileage doesnt mean everything, its 50 yrs old elec components can and do break down over time

it runs well after its started?

[Milan]

Runs good after bump start.

The PO rode it out of where he was at, at the show to me.

M

[m in sc]

My opinion.. id start with the coil and plug cap. a corroded inner plug wire can cause initial firing issues as well. once running, the magneto coil will produce enough voltage tp push the power through high resistance that may be present due to corrosion. .02

[Milan]

PO gave me the parts list & workshop manual.

So I will test the coil & plug wire resistance to spec

May have some spare wire & cap in my parts cabinet.

First Rotary Valve 2 stroke I have seen as well

M

[m in sc]

they run well. my 67 is a rotary earlier version of the same motor, they run well. my old 71 G3 ran ok but the transmission was just garbage.

[Milan]

Hope the 74 has an updated transmission fix then.

M

[Striker1423]

I had a 72 G3SS. I ran the shit out of it, then it started kicking out of 5th gear. Same as Mark's comment above haha. Was a sweet bike though. Had a 7 tooth larger rear sprocket on it, so it topped out at like 55, 60, but got there in a hurry.

[Dvsrd]

It may even be the flywheel magnets that have weakened over time. I experienced that on a Villiers 12D engine (50s vintage125 cc 2 stroke)
I had a guy re-magnetize the flywheel, and it became a one kick starter.

[Milan]

Had not spent much time troubleshooting.

So last nite I tool the spark plug off, and set it on the fins.
Kicked & no spark.

Re-gapped at 0.028 was a little large

Tested the ignition coil:
     Primary = 2.6
     Secondary = 10.7K

Was looking through my cabinet & came across a flywheel puller I did not know I had.

So pulled the flywheel and coil plate.
Installed the new coil plate & flywheel.
Checked the timing per manual = all OK.

Kicked it over.

Still no spark.

The main wire running to the ignition coil. also splits off to the ignition switch.
Per the wiring diagram, in off, it is grounded.
So I pulled that wire.

Still no spark.

It was getting late and dark, so I did not try to bump start it.

So what to test next.
The ignition coil is grounded tot he bike via a spacer, so I will check that ground loop.

M