Big time vibration

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Posts: 39
Joined: Thu Jun 10, 2004 4:01 pm
Location: Boca Raton, FL

Big time vibration


Post by PhilB » Mon Jan 19, 2009 1:16 pm

Author: PhilB

I just got a ridgid frame bike with a new (1999) 88" S & S Pan motor. It runs great and puts out lots of power but the motor puts out some intense vibration! I have to work to hang on to the bars! This is my first pan and I love the d**n thing but is the vibration typical? It starts right up, ildles well and runs through the whole power band like a monster but I just don't know about that vibration. It I had a '99 evo before and I have a 2002 Road King now so I am a used to the new bikes. Is this the nature of the pans?

Post by Cotten

First off, let's hope that whomever assembled the motor did it reasonably right. (There's BIG differences between S&S motors assembled AT S&S, compared to the zillions of others putting out their own assemblies using S&S parts. If it's a CCI unit, might want to just burn it.)
Past that aspect, vibrations that you feel are usually magnified by your chassis. When you hit a particular rpm that resonates with your chassis, it gets smooth. When it gets dissonant (like an out of tune musical instrument) it will get your attention.
The V-twin motor design will alway have vibes, but ideally they are as acceptable as riding a horse. The gait and hoofstomp correspond to your sprockets and balance factor. When in "tune", they can be pleasureable. (Particularly for the ladies, I'm told!)
Any unbearable harmonics are a signal of a loose motormount, stressed powertrain member (chains and sprockets), or ultimately, something about to frag in the motor.

Not very reassuring, am I?

Do a full-chassis tighten-up and inspection. Re-time and tune the motor. I have even encountered minor intake manifold leaks that would make the motor "ratchet" if not accellerating or deaccellerating: it could not hold a constant city-street speed without agony. Curing the minor leak made her 'normal'.

Post by PhilB

Your advice sounds logical and I will go over the bike from end to end. The motor is from the Panzer factory in Colorado. I had thought they built a good bike but I dont know. It starts and runs very well but in the mid and upper rpm range, it vibrates hard. I ran 150 miles this sunday at varing speeds but about 75 miles were at highway speeds 60-70 mph and the chain guard broke off at the trans and the left front fuel tank mount cracked! The bike has about 5400 miles on since new in 1999 so I hope the motor is tight but I know the previous owner had a manifold leak problem but he thought he fixed it.
I will see what the shop has to say as they are old school bikers and do a lot of work on pans and shovel heads. I am worried!

Post by 57stroker

A couple of weekends ago, I did about 500 miles on my Pan. The majority of it was on back roads at about 60 - 65 mph. The return trip was on the freeway, cruising 75 to 80 with short bursts up to 95 mph. (It's just too much fun! - can't help myself!) Over the next 2 days, I discovered the price for my foolishness. My 5 gallon fatbob tanks were cracked in 3 places, it rattled my motor sprocket shaft seal until it started leaking and cracked one of the top end oil lines coming out of the oil pump. Is this the nature of stroker Pans? Does going to a smaller rear sprocket help this? An old Panhead rider I know says that gearing the bike up may make it un-ridable in town. I don't remember the motor buzzing this bad last summer before I went to the stoker flywheels. On a positive note, the motor has unbelievable torque. At 75 mph, a car doing 80 to 85 can start to pass you and if you roll on the throttle, the car CAN'T get past you. In other words, in less than a car length, you can accelerate form 75 to 95 mph! And I thought my Sportster was fast! Did the shop find out anything on your bike PhilB? I'm going to do some checking on it today as Cotten suggested. My new tanks should be here tomorrow, I think the new tanks that came in the basket were el cheapo's, as I can't find anyone's name on them. It's just real discouraging to dump thousands into this bike and then not be able to cruise at freeway speeds without these kind of problems.

Post by panomania

hey phil, just wandering if you vibration was the nature of your bike or if you ever found a problem?

Post by Jack Hester

PhilB and All -

Remove the top motormount bolt completely. Make sure that the bottom mount bolts are snug. Inspect the top motor mount for cracks, and check to see if there is a gap between it and the frame. If there is a gap, put the appropriate sized shims in to make up the clearance, and tighten. Never pull the gap closed with tightening, alone. You will vibrate your eyeballs out of their sockets, and many things will fall from your bike in a short while. If no cracks or gaps found, you will have to check the entire setup for alignment. Check the primary chain. I have personally experienced a stretched primary chain that would not smooth out until above 70 mph. It happened at the Grand Canyon. Hit a huge pothole, at night, that should have killed me. Ruined the rear chain, too. I was headed for N. Carolina. Replaced the rear chain first. Vibration would not go away. Pulled the primary, and rolled the engine, with bike in gear (76 FLH). Found the bad spot. Very bad, too. A Diamond chain, and not a cheap one. Anyway, just a couple more things to look at, along with the good suggestions from the others.


Post by Philb

Found the problem! Who ever put this together last time had the top motor mount assembled upside down! They put the top mount on first (with the bracket assembled wrong) and then tightend the front mount and then the rear! The top mount was pulling on the frame so hard, when we loosend the top mount bolt and the frame sprung so hard the mounting bolt jammed at a 45' angle and we had to drive it out with a punch! After we loosend the other mount bolts and realized the top mount was assembled wrong (the L shaped bracket was bolted to the bottom of the motor bracket-so to get it to line up with the frame mount, it could only be attached first). The whole frame was sprung! Now when we reassembled the mounts with the rear, front and then top, it fits like a glove (not an O.J. Simpson Glove, either)! All the mounts line up and no stress on any of the bolts! Smooth as silk, now!

Post by panomania


Post by PhilB

Hey! Every thing is now smooth as silk! I did go to a belt drive in an enclosed primary so it is really nice-Now when I get to 55 mph I can still hang on to the bars and see the road! My last trip before I took it apart the chain guard broke off as well as two tank mounts cracking! The speedo was turning around inside the dash from the vibration! Now, it is very well mannered! What an inprovement!

Post by billy

Sounds like Happy Days are here again!!! ;D ;D

JACK, Excellent advice!!!

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Re: Big time vibration


Post by 58flh » Wed Dec 14, 2011 2:09 pm

Hey guys---Now I know you guys know that when dealing with a RIGID its whole other set of rules!. I have a 58flh in a RIGID frame! I can pick-up instantly if its a chain or loose valve adj. just from the vibration! All I ride is my pan yearound,-I lay it up every 2yrs. for a complete teardown! & when theres Ice on the roads she dont roll until the salt & ploes do thier thing. Any way If you are new to a rigid framed bike-You will see how fast your preventive maintenance routine developes! It could be 300 to 500 miles before you have to go over entire machine! Both chains tranny any bolts you can see! Will need tending to! Now this is also depends how hard you push-it & the stage of condition your bike is in! I usually go-over at 500miles, I know my bike!--If im heading south on I-95 to daytona thats a 1100 mile run for me! The Hiway is smooth asphalt, nice on a RIGID.I will only stop for fuel-ups & a rear chain-adj. 1time!-& ofcoarse the normal oil-level-clutch ,check for leaks & tire pressure!Off I go, When Im there thats when the all the ADJ. starts. If your rodes are crude as mine are in N.J. THen you have to know your bike & routine adj. for a NICE-ROLLIN MACHINE! I wrote this for the new guys with thier first RIGID FRAME bikes only! EVERYONE ELSE KNOWS the DEAL!--(GOOD-LUCK TO ALL)-58flh 8)

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