QuestionRoy thanks for response...I have shut down at speed,and the ride is perfect. The vibration is between 2500 to 3000 rpm ,in fourt or fifth,at about 55 to 60 mph ,which to me , is normal running in traffic.The dealer soluton was to really and looseen the drive belt,which seemed to loosen the drive belt,but did nothing.and said all DYNA,S have some vibration.BUT WHY NOW AFTER 10 YEARS,AND 10000 MLL. Thanks for your comments and thoughts...DAC
-------------------------------------------
The text above is a follow-up to ...
-----Question-----
I am org. owner of 96 Dyna,with 11000 mils.About 2000 mls.ago,developed a roughness in engine after warmed up or about 12miles of running.Most noticeable in 4th and 5th gear under throttle,almost like running at 1 7/8 capacity.I replaced anddid the following...new rear tire,new front and rear motor mts.,checked and adj. belt to spec.,installed self adjusting primary chain kit,replaced intake manifold gaskets,replaced coil,and module,installed s/e air cleaner and jettd carb slow jet to.45,bike burns clean,runs great to warm up ,uses no oil,gets excell mpg...
Local HD dealer said he is stumped!Recently put on DYNO and can see and feel rear fender shake and vibrate at rpm stated when reaching operating temp...DYNO guy said he can,t figure ...but maybe a clutch or trans bearing,but no noise or looseness evident after taking off outr. primary case ...I am just about out of spit,and any comments or help would be great...thanx DAC
best
-----Answer-----
Dave, I hate to say it but this is one of those problems where I really need to see, hear, and feel the bike. It's not clear from your description whether it's an engine vibration or chassis- related. Have you tried shutting off the engine at speed and coasting to see if it disappears. You didn't say exactly what rpm range it's happening at. I'm sure you are aware that all Dynas experience more vibration due to engine harmonics right around 2000 rpm. The only solution for that is to upshift or downshift and not ride steadily at 2K rpm. Is your VOES working OK? You mentioned front and rear motor mounts but said nothing about the top mount which is the one that frequently causes vibration when the two bracket bolts that go into the cylinder head loosen up. If the primary chain is too TIGHT you will get vibration. I'm as frustrated as you when I get questions like this because it's a "I need to take it for a roadtest" problem. I find it hard to believe your dealer doesn't have someone who can pinpoint it. Sorry I can't be more helpful.
AnswerDave, now that I understand your vibration more I would look at your primary drive setup. Make sure the sprocket shaft nut is tight and the alternator rotor isn't rattling on the shaft. Then I would check the inner primary bearing (on the transmission mainshaft), that's the most common recurring problem. If you replace it, make sure it is a press fit in the inner primary. I've seen them where it appears that the bearing is bad but the outer race is loose in the inner primary. Good Luck.
