[MikeyC85]

Hi guys -
Working on my daughters Apache Tomahawk 50cc (GY6 engine I believe).
Wouldn’t start, noticed that the stator Magneto wasn’t turning with the engine.
Stripped it down fully expecting the woodruff key to be sheered/moved however this wasn’t the case.

It appears instead that the shaft itself isn’t engaging and/or is engaging intermittently as the engine turns over which is effecting spark timing.

Any ideas on what could be the problem - I’m at a loss!!

 

[Mech]

The crank will be broken.

 

[MikeyC85]

The crank will be broken.

You were exactly right!!! Doh!

 

[Mech]

Bummer.. And can you get parts for those ?

 

[MikeyC85]

Luckily yes - GY6 engine so extremely common in scooters etc. Managed to source one for around $40 and another $15 for the gasket set to build her back up. Fingers crossed it goes back together ok

 

[Mech]

Ok.. good stuff.
It could be that that's a weakness with them.. I'd inspect the new crank real carefully in that spot looking for cracks or different looking texture to the metal. If you tap a cracked component they sound different too. Solid metal rings, things with a crack in them sound dull.. If you have the bearings off and tap both side shafts they should both ring, if one sounds dull it's suspect.

 

[Mech]

Might also be a good idea to check the flywheel is running true when you put it back on there as well.. An out of center or unbalanced flywheel is the only other thing that would crack the crank there I think.. other than being a badly made crank. If the key doesn't sit in it's slot well they can cause the flywheel to not sit right..

 

[MikeyC85]

Will do. Really appreciate the advice Mech!

Always learning 👍🏻

 

[Mech]

My pleasure then..