Hello,

I have a 98 dyna wideglide i bought new which has just turned over to 80,000 miles. This is my second summer of a highway daily commute of 100 miles and I'm getting an engine vibration from 70mph to 80mph. i've changed both motor mounts and did the run for a minute with them loose before tightening. I also shimmed the space in the front mount. I checked the top stabilizer..it isn't moving side to side. The vibration was bad from 70 up before I changed Mounts (the first time in 11 yrs) so it's better now...

But, the bike runs perfectly smooth from 0 to 70, then once i've gotten past the 70-80 vibration, it's smooth again from 80-90+ I can either cruze at 65 on the highway or crank it up to 80 plus and run smooth all day.

I had 2 new tires with wheel bearings inspected and repacked from a HD dealership this spring, new lifters last year also.

I'm starting to think maybe the ignition module, Senser, or maybe VOES is acting up to affect the running of the bike or theres some problems with pistons or crankshafts moving at that rpm...

So, any ideas out there?

 

Hmmm.. that's a tough one! But the fact that you have 80,000 miles on your scoot is AWESOME!

 

Are you sure your rims are trued completely and also tires/rims balanced out? That's usually the speed problems surface with unbalanced wheels/tires

 

with 80k I would go thru the engine either way... jmo

 

Yeah... I'm assuming the hd dealership correctly balanced them but you never know... I do plan to redo the motor, but i wanted to hit 100k, first then go BIGGER (bore and headwork)

I'm just gonna keep runnin' it til i figure it out or she blows

 

if the vibration is caused by speed rather than what rpm your running i would be sure and check out everything else before tearing the engine down

 

+1 with ynots!

 

+2 for sure.

 

From what you are saying it doesn't sound like it the motor. I would start looking the bike over for other problems. And 80k isn't that high of miles IMHO. I have seen motors run twice that.

 

Try this. Get in to the speed range that you are having the vibration but do it in a lower gear. This will put your rpm in a higher range. If the vibration is still there you have pretty much just ruled out the motor being the problem and you can start looking elsewhere. If the vibration starts at a slower speed while your in the lower gear then it is more than likely in that same rpm range and it is probably motor related. A tach would be helpful to narrow it down but not absolutely necessary.