Dyna Engine Balancing
Seasoned HDF Member
Joined: Apr 2014
Posts: 5,809
Likes: 2,549
From: UK
I'll take a shot at this....
Somewhat
Yes
Improvement to a degree
My reasoning is that yes, balancing the moving parts of the motor will help reduce vibration, but it will never eliminate it. Balance and true the crank and flywheels, balance the weight of the con rods, pistons and associated gubbins.
Has it been done before - yes. Many, many times. If you have the bottom end out, you almost owe it to yourself to do this anyway. Plus make sure to have crank welded so it won't "scissor" in later life if you increase the power.
And....difficult to quantify, but a definite improvement, plus a more bulletproof bottom end less likely to shake itself apart under high stress.
It's all good - go for it. Just find a competent professional to do it for you unless you are highly skilled yourself!
Somewhat
Yes
Improvement to a degree
My reasoning is that yes, balancing the moving parts of the motor will help reduce vibration, but it will never eliminate it. Balance and true the crank and flywheels, balance the weight of the con rods, pistons and associated gubbins.
Has it been done before - yes. Many, many times. If you have the bottom end out, you almost owe it to yourself to do this anyway. Plus make sure to have crank welded so it won't "scissor" in later life if you increase the power.
And....difficult to quantify, but a definite improvement, plus a more bulletproof bottom end less likely to shake itself apart under high stress.
It's all good - go for it. Just find a competent professional to do it for you unless you are highly skilled yourself!
Thread Starter
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Cruiser
Joined: Aug 2009
Posts: 115
Likes: 1
From: Portland, Oregon
I had a 2010 Heritage which I traded for a 2015 Street Glide. The snap and immediate response to throttle of the SG is obvious compared to the Heritage. The counter balancer has inertia which limits response. It's smoother but it robs power, torque and throttle response. I have ridden Dynas and the difference in acceleration and response (the "snap") is big. Vibration is shocking, particularly before break in. Same with the Street Glide.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,830
Likes: 7,968
From: poway
You can only balance a V twin to about 50% on the reciprocating mass. It will always vibrate.. If you balance an HD to 100% you won't get any vibrations in the vertical axis but will get 100% in the horizontal axis. Many have what the call secret balance factors that the claim reduce vibes but really what they've found was a certain chassis that seems to reduce vibrations.. It may not apply to another setup. One thing that does help with balancing is to make sure that the rod end / piston assembly weights are the same. HD finally caved in on the M8 and added a counter rotating balancer to the rubber mounted touring models. Wonder why it's counter rotating? Well the imbalance of the crankshaft actually rotates in the opposite direction of the crankshaft.
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Cruiser
Joined: Aug 2009
Posts: 115
Likes: 1
From: Portland, Oregon
I expect a 45 degree to vibrate, just wondering how much can the vibration be controlled by balancing the weights of the pistons, connecting rods, static and dynamic balancing of the flywheel, etc. Baisley Hi Performance claims to have one of those secret balancing factors:
http://www.baisley.com/
I wonder if any of the forum members have any experience with them.
http://www.baisley.com/
I wonder if any of the forum members have any experience with them.
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Seasoned HDF Member
Joined: Apr 2014
Posts: 5,809
Likes: 2,549
From: UK
Can't tell you yet, but I am currently having my Shovelhead engine balanced, trued and blueprinted to metric bike tolerances.
I'll let you know what my feeling is on the vibration after it's done.
But i still expect it will vibrate quite a lot - it's a 45 degree V-twin hard mounted to the frame :-)
And i like the vibes!
I'll let you know what my feeling is on the vibration after it's done.
But i still expect it will vibrate quite a lot - it's a 45 degree V-twin hard mounted to the frame :-)
And i like the vibes!
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Thread Starter
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Cruiser
Joined: Aug 2009
Posts: 115
Likes: 1
From: Portland, Oregon
Can't tell you yet, but I am currently having my Shovelhead engine balanced, trued and blueprinted to metric bike tolerances.
I'll let you know what my feeling is on the vibration after it's done.
But i still expect it will vibrate quite a lot - it's a 45 degree V-twin hard mounted to the frame :-)
And i like the vibes!
I'll let you know what my feeling is on the vibration after it's done.
But i still expect it will vibrate quite a lot - it's a 45 degree V-twin hard mounted to the frame :-)
And i like the vibes!
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