bad vibeation when down shifting after about 50 mile of riding

[hardcorejamie]

I have a 1985 flht with a five speed after i ride about 50-60 miles i get a bad viberation when down shifting if i pull the clutch its go away. very confused any ideas would help thanks

[guido4198]

Pull the Derby Cover and check the tension on the primary chain. If it is within Spec., you'll most likely need to pull the outer primary and check EVERYTHING in the drive system. 

[Porkchop]

Make sure you check the clutch hub, the originals are known to crack  and when they go it'll take out the tapered mainshaft.  My clutch was acting funny just before mine went.

[guido4198]

Like Porkchop said....That's one of the "drive system" parts I was referring to.
That clutch hub drum in the mid-80's was a sort of weak spot. Mine lasted into the late 90's, and something like 125,000 mi. give or take a few before I found a couple of the studs broke at their bases. Fortunately, no other damage was done. 

[hardcorejamie]

Thanks I found the primary chain lose and the final drive worn out going on a trip with it tomorrow hopefully its fixed

[Flat Dog]

Hope you checked the mounts as well-that was the 1st thing I would have looked into.