I got the cart ahead of the horse on this first one from a second hand store.
I do not have prop balancer, coming Jan 7th, but I went ahead and removed the spring 'dogs' and knocked out the steel pins on the flywheel.
I do not have a reference location for the original balance point.
These things are mass produced and I bet that all the flywheels new, balance within a few degrees of each other.

1) Is my logic correct?

2) If so, does anyone have records that show where your's and your buddies flywheels heavy point were before modifying? (Like maybe with the center between the magnets at a 12:00 clock position, view from front, at what time location was the heavy point.
Or with that location as reference 0 degrees what angle, 360 degree basis, from center of flywheel?

It is my understanding from reading the thread that it is important to balance back to the original heavy spot to offset some internal parts of engine.

Thanks for the assist. (In need of guidance)
mikenlapaz

I balanced mine neutral and the Ryobi runs fine. It doesn't vibrate anymore than my Homelites or McCullough's. I'm away from home but it was heavy dead center on the magnets or 180 out if I remember correctly.

Jim

Some agree & some dont -but- I personally wouldnt recomend balancing your flywheel w/ a prop balancer. These flywheels are not Static balanced from the factory but Dynamic balanced. Think of this just as a car tire being "spin" balanced when you have a new set put on. Your engine will probably spend more time running at operating speed than it will at idle so you will more than likely want it to be balanced for operating speed - just like you would your tires! Even before the engine is removed from the original equipment it has some vibration at idle and smooths out as throttle is applied. I would recomend having the flywheel machined by someone who knows what there doing if you have it machined - again - some do & some dont. They will probably not have the equipment to "spin" balance it either (to expensive for flywheels!) but will have the equipment to indicate it in there lathe & remove the material uniformaly to keep it as close to the factory balance as possible. One more thought, you are right these things are mass produced from nothing else than castings and not every casting will balance exactly the same. If they were balanced AT ALL there would be evidence of material being removed from the heavy side as you dont add anything. I have converted to many of the Ryobis & Homelights to count for myself & others and have yet to run across a flywheel that showed evidence that an attempt to balance it had been made. Sure they are very close as castings but remember they are just that "castings"! If they were balanced perfect from the factory the common weedeater would cost alot more than they do!
My 2 cents worth from an ex Borg Warner Turbo Systems compressor wheel balancer!

I'm back home and I looked at it a moment ago and it was heavy by 2 or 3 oz's on the magnet side.

If the thing was ever dynamically balanced, it had to be while the prototype was mounted on the rest of the engine and the whole assembly spun up to 7,000?

There's no evidence of it having been balanced after being die cast. There was absoluty no tooling to touch it except to touch - up the flashing a little and they didn't do much of that.

The key is even cast into the taper.

But it doesn't vibrate any more than any of my other gas engines after balancing the flywheel to neutral.

I first machined the fins down even with the counter balance, then I decided to check the balance and was amazed at how far off it was. But considering the way the rest of the engine is made..... it figures.

I've had this thing for 17 years and it has always run just fine.

To be heavy on the magnet end doesn't make much sense as far as balancing the engine because this side of the flywheel is almost oposite the counter weight on the crank.

Jim

Thanks for the input. I have two more Ryobis disassembled and getting converted. I will wait till prop balancer arrives before having the other flywheels turned.

At least I will have a static references even if I never use it.

One engine still had some casting alum OVER a large part of the magnets. It also had much more carbon in the exhaust port (over 60% closed off, a frozen ring and a lot of varnish (?) residue in the lower end. Cleaned up OK. (Used oven cleaner on the piston to help loosen the ring, which broke but made a great to fit scraper, once it was dressed on grinder, to clean the ring recess.)

Would the Alum over the magnet reduce the magnetic field enough to have given a reduced spark to the plug over its lifetime to date?

My thought is to have it turned down uniformly till just the magnet is lightly surfaced. The gap had to be wide for its life to date.

Any problem in just facing the magnets while in the lathe?

Mike

I'd be careful around the magnets. They have a crystaline structure and may shatter? The machinist may know? Best to just be careful and get as close as you can without actually touching the magnet.

He may have to come up with a mandrel to turn the OD because they usually chuck the flywheel in a 3 jaw on the OD in order to face the fins off.

The Phelon brand of flywheel and coil are rather weak in the spark department anyway. You have to wait until after dark to see a yellowish spark. The Walbro's will give a blue spark but they are rare on a Ryobi.

The die casting having flashing over the magnets would definetly cause a greater coil spacing and a weaker spark.

The later Ryobi's with the small muffler outlet were bad about getting carboned up. Especially if you set the mixture a little richer and You have to run them wide open throttle all the time to help keep the carbon out.

The early ones with the 1/2" exhaust never seemed to have any trouble.

Jim