I never really noticed it before but what’s up with the two different types of balancing gears for the FL350. Specifically the one that goes on the crank.

Well there appears to be several different styles then.
The pic below is the gears on my brothers Engine.
Obviously a lot different than yours.
Unfortunately I don't have any pics of my other 4 engines.
CO

I wonder if each counter balancer and gear set are matched ??
CO

I am also curious. I have a few with the 2 holes drilled and also the solid ones....

You think I should try weighing the balancer weight itself and see if the are all the same? Could this be part of the recall on the engines as they went with a smaller piston?

You could weigh them but how do we interpret those results ??
What were the piston weights at the time of install ??
Next we have evidence that there are at least 3 different gear sets (Mine in the pic and the two different sets you have).

Quote: "Could this be part of the recall on the engines as they went with a smaller piston?"
That sure makes sense to me. But we have 3 different sets here .
CO

If you don't get the balance factor correct on an Engine it will vibrate itself to death.
I know that in the late 1970's the CR500 didn't have a counter balancer and it was known as a vibrator. Also rppjr showed pics of an oddy Engine that had the counter balancer completely removed (for racing) and it also had a busted case right at the Engine mount. I bet my rent money they got the balance factor wrong. Who knows what Honda did here.
CO

So... would it be safe to say that the correct gear should be the one with 2 holes drilled though it? Like the one you shared a photo of?

I want to put this Engine together once, the correct way.

The service manual shows the one with 2 holes.... ?!?

I have the one with 2 holes, and since I have an Engine currently disassembled on the bench, I put the balancer on a scale weighs 830g.
This was a post-recall Engine, Maybe that does have something to do with it as you suggested?
But I also don't see why it would matter unless the timing marks are in different spots?

Looks like the service manual wants us to use those holes to hold the crank in place while removing the nut on the driven gear.


CO,
I don't see how yours is different than the right one in Curtis' picture. It has the same 2 holes, no?

I think I may have misinterpreted what Curtis was showing and saying there.
His pic shows both styles of CRANK gear. I thought he was showing the complete set (counter and crank gears).
Yes you are right. In the pic Curtis posted the left gear is the correct CRANK gear as the rest of us have. The right gear is obviously different and I don't know why.
You are also correct in the two holes for holding the gear while tightening the nut.
Either way that gear on the right is different and not sure why. As long as it is balanced I can't see why it would be a problem other than that you can't hold it while tightening the crank nut. It's possible Honda figured out that boo boo and fixed it during the recall. That solid gear might be pre-recall.
CO

Yes... the photo I posted is the same gear to show the difference between them. I’m going to go ahead with the drilled gear.

With the un-drilled gear... As long as you remove the crank nut first... You can remove the crank nut by holding the weight gear.

Up until a few years ago I was a CR500 guy (age comes the cage) ya they vibrate but you get used to it, you learn not to hold on too tight or your hands will go to sleep.
I also put a CR Engine into a quad, lots say it won't work because of the vibration but I didn't notice any more vibration in the quad than the bike, the quad was a Cannondale aluminum frame, I think that helped some. that was a project I had wanted to do and by the time I had finished my knees were too bad to be able to use it much and had to sell.
as for the gears, I don't think it would hurt to use either, the one with holes is just more race with lightening holes and as CO stated easier to hold while tightening the crank nut.