Excessive Engine Vibration or Normal?
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Intermediate
Joined: Sep 2024
Posts: 35
Likes: 25
From: Tulsa OK
But with a rigid mount motor, I remember that hot setup was to balance towards 60%. Going lighter pistons will bring the balance factor closer to 60%.
FWIW I wonder if pick up in vibes resulted from the motor having a higher compression ratio and it's making more power. Also since the combustion efficiency has increased, the motor needs less timing.
FWIW I wonder if pick up in vibes resulted from the motor having a higher compression ratio and it's making more power. Also since the combustion efficiency has increased, the motor needs less timing.
Last edited by Lando Evo; Oct 14, 2024 at 12:43 PM.
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From: NC USA
Max, the few I measured were late 80' and early 90's they were 60% All 45 degree engines will vibrate to some degree at some rpm range. 60% gives the tightest range and is smoothest overall, according to the Indian designers who went strictly by trial and error... over and over til they got it. The factor is only relevant to the moving parts - power to the parts has nothing to do with it.
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From: poway
Counter clock-wise retards.
Max, the few I measured were late 80' and early 90's they were 60% All 45 degree engines will vibrate to some degree at some rpm range. 60% gives the tightest range and is smoothest overall, according to the Indian designers who went strictly by trial and error... over and over til they got it. The factor is only relevant to the moving parts - power to the parts has nothing to do with it.
Max, the few I measured were late 80' and early 90's they were 60% All 45 degree engines will vibrate to some degree at some rpm range. 60% gives the tightest range and is smoothest overall, according to the Indian designers who went strictly by trial and error... over and over til they got it. The factor is only relevant to the moving parts - power to the parts has nothing to do with it.
I'll agree that power has nothing to do with balance factor but it has a lot to do with vibration when transmitting power.
Add:
This guy has a good discussion.
http://www.brufnut.de/SS100/ENGINE/C...nk_balance.htm
This a another one but single cylinder..
https://motochassis.com/Articles/Eng...ineBalance.pdf
Last edited by Max Headflow; Oct 14, 2024 at 03:06 PM.
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From: la la land jerzey
We balance everything we do - and racing you lower the number to the short 50s as you want the balance to come in at hi RPMs like road racing that we did with buells
street hot rods the old man at S&S was bolted on street strokers equal weight wheels the most used numbers were 60 percent big twin
doing a military hang and backing it up to what is done up to evo - dont care about Twinkies that’s a cand]adian thing goggling over Twinkies
57 percent was the old ideas but they did not have hi ways we now have even flat side motors were set around 57 percent from the motor company unequal wheels one heavy one lighter and both heavier then the evo set ether side
S&S wheels are equal weight both sides and 60 percent is what is recommended - does it work yea for street manners
the issue i see from what you have answered — you said your timing with a ultima ignition is almost all the way clockwise - that would be are 47 or 48 degrees of timing — hi compression to keep it from SPARK KNOCKING and i believe that is your vibration issue
while it has more power your wallet is not going to trashed by that use of timing - we even if the the day when egos were all the rage let one go like you have
it didn’t work then and wont now - have some one in the know tune it to LAST with what you have and be happy with that
street hot rods the old man at S&S was bolted on street strokers equal weight wheels the most used numbers were 60 percent big twin
doing a military hang and backing it up to what is done up to evo - dont care about Twinkies that’s a cand]adian thing goggling over Twinkies
57 percent was the old ideas but they did not have hi ways we now have even flat side motors were set around 57 percent from the motor company unequal wheels one heavy one lighter and both heavier then the evo set ether side
S&S wheels are equal weight both sides and 60 percent is what is recommended - does it work yea for street manners
the issue i see from what you have answered — you said your timing with a ultima ignition is almost all the way clockwise - that would be are 47 or 48 degrees of timing — hi compression to keep it from SPARK KNOCKING and i believe that is your vibration issue
while it has more power your wallet is not going to trashed by that use of timing - we even if the the day when egos were all the rage let one go like you have
it didn’t work then and wont now - have some one in the know tune it to LAST with what you have and be happy with that
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From: NC USA
Just dawned on reading johns post, if it's turned near all the way clockwise, I wonder if you timed it on the wrong stroke. Yeah, that'll make some serious vibration.
Go back and make sure you're on compression stroke of the front cylinder when you find the line.
Go back and make sure you're on compression stroke of the front cylinder when you find the line.
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From: Cental, MI
BTW all the way clockwise would be alot of Advance if timed on correct cylinder...Me Thinks
Mine would Kick back on the starter if I did that...But...I have Zero dead revs!
FWIW all the way counter clockwise..(severely Retarded) would generate exhaust heat...Fast!!!
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Intermediate
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From: Tulsa OK
Last edited by Lando Evo; Oct 14, 2024 at 06:58 PM.
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Thread Starter
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Intermediate
Joined: Sep 2024
Posts: 35
Likes: 25
From: Tulsa OK
Happens so Very Often!!!
BTW all the way clockwise would be alot of Advance if timed on correct cylinder...Me Thinks
Mine would Kick back on the starter if I did that...But...I have Zero dead revs!
FWIW all the way counter clockwise..(severely Retarded) would generate exhaust heat...Fast!!!
BTW all the way clockwise would be alot of Advance if timed on correct cylinder...Me Thinks
Mine would Kick back on the starter if I did that...But...I have Zero dead revs!
FWIW all the way counter clockwise..(severely Retarded) would generate exhaust heat...Fast!!!
Thread Starter
|
Intermediate
Joined: Sep 2024
Posts: 35
Likes: 25
From: Tulsa OK
We balance everything we do - and racing you lower the number to the short 50s as you want the balance to come in at hi RPMs like road racing that we did with buells
street hot rods the old man at S&S was bolted on street strokers equal weight wheels the most used numbers were 60 percent big twin
doing a military hang and backing it up to what is done up to evo - dont care about Twinkies thats a cand]adian thing goggling over Twinkies
57 percent was the old ideas but they did not have hi ways we now have even flat side motors were set around 57 percent from the motor company unequal wheels one heavy one lighter and both heavier then the evo set ether side
S&S wheels are equal weight both sides and 60 percent is what is recommended - does it work yea for street manners
the issue i see from what you have answered you said your timing with a ultima ignition is almost all the way clockwise - that would be are 47 or 48 degrees of timing hi compression to keep it from SPARK KNOCKING and i believe that is your vibration issue
while it has more power your wallet is not going to trashed by that use of timing - we even if the the day when egos were all the rage let one go like you have
it didnt work then and wont now - have some one in the know tune it to LAST with what you have and be happy with that
street hot rods the old man at S&S was bolted on street strokers equal weight wheels the most used numbers were 60 percent big twin
doing a military hang and backing it up to what is done up to evo - dont care about Twinkies thats a cand]adian thing goggling over Twinkies
57 percent was the old ideas but they did not have hi ways we now have even flat side motors were set around 57 percent from the motor company unequal wheels one heavy one lighter and both heavier then the evo set ether side
S&S wheels are equal weight both sides and 60 percent is what is recommended - does it work yea for street manners
the issue i see from what you have answered you said your timing with a ultima ignition is almost all the way clockwise - that would be are 47 or 48 degrees of timing hi compression to keep it from SPARK KNOCKING and i believe that is your vibration issue
while it has more power your wallet is not going to trashed by that use of timing - we even if the the day when egos were all the rage let one go like you have
it didnt work then and wont now - have some one in the know tune it to LAST with what you have and be happy with that
Last edited by Lando Evo; Oct 14, 2024 at 07:08 PM.