I have a 1998 Dyna lowrider with 38,000 miles, it has a very annoying vibration right around 2000 rpm accelerating and decelerating. I have replaced both motor mounts, the top link is tight and the wheel alignment is correct. I have done the motor alignment process by loosening the mount bolts, running it for about a minute and retorqueing them. Riding around it's pretty good, on the highway it's real smooth. I have tried it with shims of varying thickness on the motor mount and with out shims, no matter what it doesn't seem to make much difference. It seems the worse when slowing down, almost wants to shake your feet right off the pegs and fillings out of your teeth. The engine is stock with VH straight shots exhaust and screamin eagle air cleaner. I have checked the primary chain adjustment, it's at a point to where if I go one more tooth up on the adjuster it might be too tight so i put it down one now it feels a little loose, maybe on the loose end of the spec, 5/8-7/8 of an inch. The tires are good and belt tension is ok. I really like the bike but this vibration got me at my wits end. My last two bikes were softails and rode like glass all the time. I've read about crankshaft issues, but don't think thats a problem because of the smoothness at high speed. Right now I'm in the process of changing over from the cv to a mikuni 42 because whoever removed the plug covering the mixture screw kind of butchered it up and the screw won't stay adjusted. I've even thought about shimming the rear mount to see what happens. I don't if I've overlooked something or what, but I need you guys HELP!!! I'm not going to the dealer!!! I know there's some excellent home mechanics out there and would really appreciate what ever advice you guys could offer. If anyone knows of a good, reliable independent Harley mechanic in the west Georgia, Villa Rica area, I could use one of those too. Thanks-a-million guys.

 

Did you recent acquire this bike and it's always done this....or was it fine until recently? If it's the first then maybe your just a softail guy. Dynas shake and some can't get used to it. I have a 02 wide glide and sometimes I like the shaker feel and sometimes it bugs me. On the other hand if it's been fine before and this just came up then I dunno because sounds to me like you done a good job troubleshooting on your own.

I tell you now that I think back I had a similar problem. Decelerating was where the problem was for me. When I let off the throttle in 3rd gear it would buck like a mule. I cured it by adjusting the idle to where it was at a smoother running speed so when I decelerated the engine ended at a smooth idle rpm I instead of a lumpy jumpy speed. These old carb bikes will idle low and thump around a lot if you don't raise the idle a little to smooth them out. Some like it that way though and I do to depending on my mood. May or may not help you but you wanted suggestions you haven't covered so there's a thought. Although this really wouldn't factor into accelerating vibrations.

Another thing I learned about my dyna is it is very picky about what tire pressure it likes. Check those and play around and see if that helps.

Lastly....a little more detailed explanation of the symptoms will help other guys chime in. A vibration can be a vast term. Vibration where....you only mentioned pegs. Any wobble in the bars? License plate shaking up and down? Ect

 

Now that you mention it, it is more of a shake than a vibration. I've had the bike about 6 months and did it from the day I rode it home. Don't have no wobble or handlebar shaking problems. Thought about getting the vibra-technics front mount as a last resort.

 

No reason to throw money at the problem just yet! I think you are on the right track with the carb idea! I like the S&S E model as it is so readily adjustable and is so damned cool looking...but that's just me! So far I think you have been given good advice and wish I could add more to them...my cup runuth empty...good luck and keep us posted! Stay real!

 

A couple of things to consider. Its sounds like a resonance. Is it in both the bars and the pegs. If its the bars only consider the possibility of the riser mounts being the cause. Also is its predominantly near the seat or in the foot pegs then check the exhaust fixings. Loosen all the clamps and bolts holding the exhaust in place and sun it through the critical speed. If it solves the problem tighten all the bolts up one at a time and check for vibration each time. Also check clearance between the brake and shifter linkages to make sure they are not trapped by the motor.

 

My brand new Low Rider does it as well (as did the one I had for a test ride). In general is very smooth, except idle of course, but around 2100-2300rpm it shakes like it's about to fall apart. Doesn't really bother me, as most of the time I just avoid this rpm range.

 

Maybe it's because you're LUGGING THE BIKE!

 

+1 drop a gear and get those RPMs up! You're putting undue stress on the rods, bearings, compensator and gawd knows what else.

 

I saw something about, removing some rubber from the motor mount. I don't remember where I saw it. Try a google search.

 

Quote: "I'm not going to the dealer!!! I know there's some excellent home mechanics out there and would really appreciate what ever advice you guys could offer. If anyone knows of a good, reliable independent Harley mechanic in the west Georgia, Villa Rica area, I could use one of those too. Thanks-a-million guys."


I live near you, in Douglasville, and recently saw a posting on craigslist that was titled:
Harley Service (Villa Rica, West Ga)-Guy claims to be a certified Harley Tech- 404-427-8746.
I don't know anything about him or his abilities but saved the posting for possible future use. If you end up using him let me know how it turns out.