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Cant figure it out? Can you guys help??

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SLICKSALZ

Member
Hi guys, new here and glad to be here. Hopefully someone can help. I have a vibration problem that doesn't seem to be like anyone else's. I have a 98 Dyna (12,000 kmi), it's been raked 4 degrees, cammed, screaming eagle ignition, piped with power cones, carb re-jeted, m6 primary chain tensor. All work done by HD mechanics. Here's the prob. Bought the bike last Spring from the orig. owner. We noticed an excessive vibration during acceleration and deceleration but only around a 2000rpm window. Bike is smooth otherwise. Bike doesn't have to be in motion for vib. to happen. Had two other harley shops plus a few other dyna riders take it for a spin and all say their definitely is a problem but no one seems to know what it is. We have replaced front and rear motor mounts (after front mount was replaced the problem went away but came back after about 30 miles of riding - I have inspected the mount and can't see anything wrong with it). Replaced the trani output main shaft bearing, verified that the primary chain was at the proper tension, did a vehicle alignment (top stabilizer link), checked engine timing, all nuts and bolts on the bike are tight. Even tried shimming the front motor mount. Nothing changed. Engine runs very well, no pinging. Where's the vib coming from???? Dyna riders have told me it's normal to have vib on the decel. but not on accel. We've lost foot pegs and mirrors it shakes so bad. Not enjoyable to ride at all. We're racking our brains. Do you think I could have gotten a bad motor mount??? Any ideas would be helpful and greatly appreciated. Sucks having a new bike that you can't even enjoy riding.
 
Have you checked the pipes to see if one of them is laying against something. See if you can determine what pert of the bike the vibes are coming from as long as you can reproduce them standing still with just the motor running.

I've heard of a few problems with the compensator sprocket causing a vibration too.
 
Its definitely in the motor / primary . It seems that when the motor reaches a certain harmonics the vibration starts. One would think that after the new front mount was installed and the problem went away that it was mount relighted . But to have it come back in 30 miles makes you wonder if I got a defective mount? When a mount goes bad can you always see a torn spot in the rubber? Dose a crank out of balance give you a content vibration or only at specific rpm ranges? I wonder what actually goes bad with the compensator sprocket?
 
The cranks in that era were pretty good and I would doubt that is where the problem is. With the compensator, there has been quite a few cases where the nut has come loose but that usually manifests itself as a knock in the engine eventually similar to a rod knock.

The mounts have also gone bad depending on engine alignment, yours could have gone bad after replacement. You can usually see the damage to the mount, recheck the mount bolts to see if they are torqued properly.
 
glider said:
The mounts have also gone bad depending on engine alignment, yours could have gone bad after replacement. You can usually see the damage to the mount, recheck the mount bolts to see if they are torqued properly.
Click to expand...

Maybe the bolt itself to small in dia. allowing just a little "slop" ??
 
glider said:
With the compensator, there has been quite a few cases where the nut has come loose but that usually manifests itself as a knock in the engine eventually similar to a rod knock.
Click to expand...

compensator nut "bottomed-out" before proper torque was established?
 
Zaakkly, you may need a shim then and are available at the dealers or mill the nut .060 and reinstall for a better torque clamp. PN [FONT=Arial,Helvetica,Sans Serif]24032-70.[/FONT]
 
The bolts in the mount are good. I even tried the whole loosen all bolts in mount and run the motor for 5 sec then re tighten trick. No luck. Im guessing its not the nut on the compensator sprocket because when I pulled the primary apart the first time to replace the trani main shaft baring (thinking this was the problem) the nut was tight and I had the vibe.
 
SLICKSALZ said:
The bolts in the mount are good. I even tried the whole loosen all bolts in mount and run the motor for 5 sec then re tighten trick. No luck. Im guessing its not the nut on the compensator sprocket because when I pulled the primary apart the first time to replace the trani main shaft baring (thinking this was the problem) the nut was tight and I had the vibe.
Click to expand...

So the vib. is at 2k rpm's sittin still and out on the road?
 
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