Vibration
Road Master
Joined: Jun 2011
Posts: 836
Likes: 230
From: Deep South
Not normal....
it's not normal for an engine to vibrate to the point which you are talking about ...if it was "normal" it would vibrate at all rpm's and any speed ....the problem you have is the timing is too advance at that rpm ...if you were to retard the timing 2-3 degrees at that spot (depending on just how bad the vibration is)...it would be as smooth as the rest of the rpm scale .....you need a tuner to be able to make adjustments in the problem area's !!!
what is happening is you are trying to drive the crank back the other way (wrong way) when the timing is too advanced ...which causes the vibration ...when correct , the motor will even accelerate better and faster and very smoothly !!!
you can ride it a 100,000 miles ...and it's not going to "run in" either !!!
everyone has "accepted " this vibration as normal operation ...when it is NOT...harley does not spend alot of time dialing in the tune for these bikes ...a one tune fits all approach is the only "normal" thing here ..!!!
how many times have you also heard that "no two bikes or motors are the same " ...yet they load the same tune in every ECM ..!!!
when the timing and AFR's are set correctly ...any motor will run smoothly !! get a tuner of some kind ...learn how to use it ...fix the problem areas ...then ENJOY THE RIDE !!
what is happening is you are trying to drive the crank back the other way (wrong way) when the timing is too advanced ...which causes the vibration ...when correct , the motor will even accelerate better and faster and very smoothly !!!
you can ride it a 100,000 miles ...and it's not going to "run in" either !!!
everyone has "accepted " this vibration as normal operation ...when it is NOT...harley does not spend alot of time dialing in the tune for these bikes ...a one tune fits all approach is the only "normal" thing here ..!!!
how many times have you also heard that "no two bikes or motors are the same " ...yet they load the same tune in every ECM ..!!!
when the timing and AFR's are set correctly ...any motor will run smoothly !! get a tuner of some kind ...learn how to use it ...fix the problem areas ...then ENJOY THE RIDE !!
Last edited by springers4ever; Dec 15, 2017 at 11:08 AM.
Stellar HDF Member
Joined: Oct 2010
Posts: 2,601
Likes: 189
From: east texas
everyone has "accepted " this vibration as normal operation ...when it is NOT...harley does not spend alot of time dialing in the tune for these bikes ...a one tune fits all approach is the only "normal" thing here ..!!!
how many times have you also heard that "no two bikes or motors are the same " ...yet they load the same tune in every ECM ..!!!
when the timing and AFR's are set correctly ...any motor will run smoothly !! get a tuner of some kind ...learn how to use it ...fix the problem areas ...then ENJOY THE RIDE !![/QUOTE]
I guess my 91 aint "any motor", It vibrates, but it is predictable.
I/E at 50 the grips shake, at 60 it transfers to the seat, at 70 the footpegs do it .
at 80 , the seat vibrates again, at 90 it blows your feet off the forwards.
btw mirrors are useless above 50.
my carb wont accept a tuner, but the timing and jetting has been moved around with no reduction in vibration.
wish I had one of those "any motors that will run smooth "
how many times have you also heard that "no two bikes or motors are the same " ...yet they load the same tune in every ECM ..!!!
when the timing and AFR's are set correctly ...any motor will run smoothly !! get a tuner of some kind ...learn how to use it ...fix the problem areas ...then ENJOY THE RIDE !![/QUOTE]
I guess my 91 aint "any motor", It vibrates, but it is predictable.
I/E at 50 the grips shake, at 60 it transfers to the seat, at 70 the footpegs do it .
at 80 , the seat vibrates again, at 90 it blows your feet off the forwards.
btw mirrors are useless above 50.
my carb wont accept a tuner, but the timing and jetting has been moved around with no reduction in vibration.
wish I had one of those "any motors that will run smooth "
Road Master
Joined: Jun 2011
Posts: 836
Likes: 230
From: Deep South
again ..you have accepted it as normal operation...
what type of ignition are you running on this carb bike ...is it even adjustable ??
can you even tell if it adjustable or not ...???
just another TROLL ....not offering any help of any kind , but seems to have an opinion about everything ...
Last edited by springers4ever; Dec 17, 2017 at 09:29 AM.
Road Warrior
Joined: Sep 2017
Posts: 1,609
Likes: 694
From: over the mountain
From Hammer performance.
Why Do Harleys Vibrate So Much? There's a physics reason behind it. With pure rotating weight only (absent any reciprocating weight) a flywheel assembly could be balanced perfectly for all rpms, i.e. it wouldn't matter how fast you spin it, it would always be in perfect balance. But connecting rods and pistons contribute reciprocating weight, and worse, the loads imparted onto the crank by reciprocating weight go up as the square of the speed increase, rather than linearly. The classic way to balance when you have reciprocating weight is to design the motor such that the loads from one rod & piston assembly offset the loads from another rod & piston assembly. However, the 45 degree common crankpin and knife & fork rod assembly make this impossible. So sans a counter balancer, we're stuck with achieving proper balance at one rpm only, with vibrations increasing as the rpm is moved further and further away from that point. Therefore, the most effective thing you can do to improve the balance on an HD motor is to minimize reciprocating weight, i.e. run lightweight connecting rods and pistons. Not only will this reduce vibration, but it will also reduce the wear and tear on the lower end, make a failure less likely, and add power. At HAMMER PERFORMANCE, we offer the lightest connecting rods and pistons in the business for exactly this reason.
In my experience...
Always check your motor mounts. Loose motor mounts will cause excessive vibration.
As will flywheel run out that is not in spec. Every now and again a bike gets out from the factory that is not in spec.
They do improve with break in. Some times as much as 2 to 3 thousand miles before every thing settles in.
Why Do Harleys Vibrate So Much? There's a physics reason behind it. With pure rotating weight only (absent any reciprocating weight) a flywheel assembly could be balanced perfectly for all rpms, i.e. it wouldn't matter how fast you spin it, it would always be in perfect balance. But connecting rods and pistons contribute reciprocating weight, and worse, the loads imparted onto the crank by reciprocating weight go up as the square of the speed increase, rather than linearly. The classic way to balance when you have reciprocating weight is to design the motor such that the loads from one rod & piston assembly offset the loads from another rod & piston assembly. However, the 45 degree common crankpin and knife & fork rod assembly make this impossible. So sans a counter balancer, we're stuck with achieving proper balance at one rpm only, with vibrations increasing as the rpm is moved further and further away from that point. Therefore, the most effective thing you can do to improve the balance on an HD motor is to minimize reciprocating weight, i.e. run lightweight connecting rods and pistons. Not only will this reduce vibration, but it will also reduce the wear and tear on the lower end, make a failure less likely, and add power. At HAMMER PERFORMANCE, we offer the lightest connecting rods and pistons in the business for exactly this reason.
In my experience...
Always check your motor mounts. Loose motor mounts will cause excessive vibration.
As will flywheel run out that is not in spec. Every now and again a bike gets out from the factory that is not in spec.
They do improve with break in. Some times as much as 2 to 3 thousand miles before every thing settles in.
Last edited by apache snow; Dec 18, 2017 at 08:11 PM.
Stellar HDF Member
Joined: Oct 2010
Posts: 2,601
Likes: 189
From: east texas
again ..you have accepted it as normal operation...
what type of ignition are you running on this carb bike ...is it even adjustable ??
can you even tell if it adjustable or not ...???
just another TROLL ....not offering any help of any kind , but seems to have an opinion about everything ...
what type of ignition are you running on this carb bike ...is it even adjustable ??
can you even tell if it adjustable or not ...???
just another TROLL ....not offering any help of any kind , but seems to have an opinion about everything ...
wow ! yes it is adjustable, be sure to put a clear plug in the timing hole,
but obviously you are the expert on everything.
you probably could have saved HD millions of $$$$ not having to design "rubber mounted " motors, and don't forget the millions spent on the 'B' motor.
BTW I have your "troll"
Road Warrior
Joined: Mar 2016
Posts: 1,713
Likes: 299
From: SC
wow ! yes it is adjustable, be sure to put a clear plug in the timing hole,
but obviously you are the expert on everything.
you probably could have saved HD millions of $$$$ not having to design "rubber mounted " motors, and don't forget the millions spent on the 'B' motor.
BTW I have your "troll"
but obviously you are the expert on everything.
you probably could have saved HD millions of $$$$ not having to design "rubber mounted " motors, and don't forget the millions spent on the 'B' motor.
BTW I have your "troll"
I never could see through those damn plastic plugs so I just get messy.
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Stellar HDF Member
Joined: Oct 2010
Posts: 2,601
Likes: 189
From: east texas
lol, yeppers, it will spit on ya
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