Billet flywheel with electric start

[AdamGar]

I’m planning a build on my first kart. I have a lightly used Honda GX270 (free) that I’d like to stage 2. I’d like to add electric start however ARC not anyone else makes a billet flywheel with that purpose. So my questions are:
1) Is an ARC billet flywheel flat enough and have enough meat that it could have a starter gear ring be added to the back by tapping threaded holes? I’ve been told that OEM electric start flywheels may grenade if mods are made to the engine.

 

[madprofessor]

OEM electric start flywheels may grenade if mods are made to the engine.

That's a fact, if you remove the 3,600 rpm governor and put in stronger valve springs. Without the stronger springs, the valves will start to float somewhere above the low5K rpm range, and you can't spin it any faster, and should be safe. I'd be more concerned about getting a billet connecting rod to save the engine.

billet flywheel flat enough and have enough meat that it could have a starter gear ring be added to the back by tapping threaded holes

No matter how well balanced and proven a flywheel is, when you start drilling out metal for bolts, add bolts, and add a ring gear, it's no longer safe at all.

 

[Kartorbust]

Only the GX390, its clones have billed flywheels with starter ring gears, as well as the GX200. Any modifications made to fit a ring gear, the flywheel would have to be re-balanced.

 

[madprofessor]

Only the GX390, its clones have billed flywheels with starter ring gears

I'm ordering a Predator 420 soon, keeping it pretty much stock, at least internally. Any idea what the stock ring geared flywheel is rated for rpm?

 

[Kartorbust]

I'd keep it no higher than 3800rpm. Chinese quality control is sketchy at best. Anything higher and the harmonics could end up breaking it and/or send the ignition magnet on the fly wheel to come off.

 

[madprofessor]

I'd keep it no higher than 3800rpm.

Reliability being the thing I'll care most about on that motor, I'll take that advice as good enough for gospel. Governor will stay in place, only an external adjustment to raise up to 3800 rpm will be done.