Are 2 stroke V6 flywheels neutral balanced?

[BQUICK]

Can they be switched from motor to motor?

[99yam40]

I really have never thought about it, but since you can buy the flywheel separately I would think they are not part of a balanced crank.
Just like pistons and rods, they all should be close enough to not need them all together and then balanced.
But if you do it that way it would be smoother I am sure.
Just like automotive motors

[boscoe99]

I really have never thought about it, but since you can buy the flywheel separately I would think they are not part of a balanced crank.
Just like pistons and rods, they all should be close enough to not need them all together and then balanced.
But if you do it that way it would be smoother I am sure.
Just like automotive motors

I second all of the above.

All two strokes I have been involved with vibrate so much I am not sure if I could tell if they were in balance or out of balance. The term "shaky jake" comes to mind. I have not been on a boat with a modern Evinrude G2 two stroke however.

Now given that they (two strokes) fire on every up stroke one might think they would run smoother than a four stroke motor that fires every other up stroke. Just has not been my experience.

[BQUICK]

So if I have a choice probably try to keep parts together. Had a like new flywheel that I was going to use but maybe keep the ugly one with it's crank and rods.

[boscoe99]

So if I have a choice probably try to keep parts together. Had a like new flywheel that I was going to use but maybe keep the ugly one with it's crank and rods.

It should not matter. But it might.

Since the motor was never balanced as an assembly the new flywheel might work better with the old pistons, connecting rods, crank shaft, etc., than the old flywheel did. No why to know for sure without trying it.

Without a vibrometer installed I suspect that an individual will not be able to tell if it is better, worse or the same.

[rodbolt17]

as long as it is the correct part number it works.
only thing I do is lap the two tapers until a pencil mark in 3 spots at 120* is erased when I set the flywheel on the crank and rotate it 90*.
the flywheel key simply indexs the flywheel it will NOT holt the flywheel that is the tapers job.

[99yam40]

good info here, I never thought about making sure the tapers on any flywheel matched up well to the shafts before

[boscoe99]

Then some folks will lubricate the taper thinking it will make the flywheel easier to remove in the future. That is true. It will.

Unfortunately it makes the flywheel "self remove" at unintended inopportune times.

[99yam40]

only keys I have sheared off were on lawn mowers when I hit something that was large enough to stop the motor suddenly.
also bent a shaft or two and blades.
without the kids around leaving tools and other stuff laying in the yard, that is a thing of the past except for up at the farm house.
trying to mow wast high stuff, you can find all sorts of stuff from time to time
I believe if a key is sheared on any motor the taper needs to be done as Rod posted

[robert graham]

as long as it is the correct part number it works.
only thing I do is lap the two tapers until a pencil mark in 3 spots at 120* is erased when I set the flywheel on the crank and rotate it 90*.
the flywheel key simply indexs the flywheel it will NOT holt the flywheel that is the tapers job.

Do you lap the taper with something like valve grinding compound or similar?

[rodbolt17]

medium or fine valve lapping compound.
when doing the final assy both tapers need to be clean and dry.

[boscoe99]

only keys I have sheared off were on lawn mowers when I hit something that was large enough to stop the motor suddenly.
also bent a shaft or two and blades.
without the kids around leaving tools and other stuff laying in the yard, that is a thing of the past except for up at the farm house.
trying to mow wast high stuff, you can find all sorts of stuff from time to time
I believe if a key is sheared on any motor the taper needs to be done as Rod posted

You left your dad's stuff in the yard to be run over by him so your kid(s) leave your stuff in the yard to be run over by you. They will get their just due when they have kids.

Sweet justice.

[boscoe99]

While the taper is very important, here is a time when a calibrated torque wrench might just come in a tad handy. Some flywheel nuts might require a buddy to help pull on the wrench to tighten the nut to its proper value, to ensure the nut does not come loose.

Methinketh I doth like the new style of Yamaha flywheel attach configuration. Even if the damn bolts are torque to yield type. At $26 bucks plus for a set of six.

[walleye1]

Bosco yoe kill me

[rodbolt17]

one version of the F250 torques to something like 205ft lbs. I think the old F225 pulled down to about 175.
not bad when I only weigh about 136.
dang gearcase on a V8 is 133 without oil.