Hello,

I have a Dyna 2006 which has got some bad vibrations. When the engine is cold, bike runs smooth. But as soon as it has warmed up a bit, there is a harsh vibration, noticeable when I let go of the throttle and the rpm is falling during shifting.

The bike has the Predator front motor mount, which I mounted last winter. It also has the PCV with Autotune and the Hayden transmission chain tensioner.

After mounting the Predator I did not do the alignment adjustment by losening and adjusting the top motor mount, (described in the Harley manual). Perhaps I will try it, although I did it a few years ago.

I have checked the belt tension with a gauge and it is fine.

So, does anyone have a clue what it could be which creates this temperature related vibration?

Best Regards to you all

 

I want to add that this vibration is also noticable standing still and that it exists within 2000-2500 rpm. I have checked the exhaust, and it does not seem to be lose. I read something about that the rear mount can be affected when the front mount collapses. There is something moving and creating unbalance in the bends. Perhaps the rear mount.

 

Another thought. The bike runs better when cold and has a more crispy throttle response. When warm it is a bit dull and it then has the vibration as mentioned above. This dullness when warm has followed the bike since I bought it. But before the breakdown of the front mount some years ago, it had no noticeable bad vibration added to it. Maybe there was, but the stock mount swallowed it.

Anyway from this I suspect that there is an internal engine problem, like a bearing or something with the compensator. I just do not know, but hope someone would give me a clue here. The former owner had it in a shed for 10 years and hardly never used it. Perhaps this has caused the problem.

 

Hello there!

Just reading your thread here, and since no one has weighed in yet, I'll take a swing.

My initial thought is that the last part of your story so far is the part that I would chase down first--I get a lot of machines brought to me to fix, or just plain given to me because "It ran fine when I put it away"...ten years ago. If it runs well when cold, then poorly when warmed up, it might be something as simple as a fuel delivery issue--perhaps dirty injectors, rust from the tank, or a degraded fuel line in the pressurized system inside the tank.

Those kinds of problems are common after having sat for extended periods of time, and can cause the symptoms you describe. Fuel injection tends to start up after storage much easier than a carbureted system, but ten years is a loooooooooong time to sit, and all kinds of things can still go bad.

All the best,

Shane

 

Thanks Shane for the input. Yes, the fuel delivery has been (or still is?) a problem. When I bought this bike in 2016 it ran like crap. Dealer replaced the 8 degrees injectors with 25 degrees and remapped the ECU. That made a big difference, although it did not give a complete cure. From then I have done things like checking the fuel pressure (which was good) and done a lot of tuning attempts with PCV/Autotune. It now runs fair, except for this remaining slight lack of throttle response at low rpm and warm engine, (nowadays accompanied with the mentioned vibration.) I have read ideas about that the PCV may not match the ECU during the warm up phase and that this may cause problems of this kind. Perhaps I will throw the PCV out and replace it with Powervision.

 

A few days ago I did the top engine mount alignment procedure, with good results in the handling. And today I pulled out the PCV (been there for 5 years), just to see if the dullness and the uncrispiness in the throttle response at warm engine would disappear. (I also had trouble with an intermittent 1500-2000 rpm idle when engine is warm.) Although the engine is out of tune with surging and decel popping, I would say the problem with dullness in throttle response at around 5-10% throttle was caused by the PCV. Next step is probably a Power Vision, to get the bike in tune.

About the vibrations: Bike still vibrates at 2200 rpm, but perhaps a little less. Maybe one can adjust the stabiliser link on the Predator mount. I do not know. I have written to Vibratech to get an advice.

 

Vibratech has answered and recommended checking that there are no contacts between the frame and the engine/transmission/ exhaust. Then they recommended supporting the rear part of the frame, loosening the center bolt in the Predator a couple of turns, running the motor for a while and the torquing the center bolt. I have done this. Still there are vibrations around 2200 rpm.

​​​​​As mentioned earlier in the thread I have already done the adjustment bringing tension out of the top stabiliser. What then can remain contacting the engine to the frame? Well, thinking of the Predator stabiliser link which actually makes this connection, and remembering someone here at the forum writing that this link should be loose and easy to turn, I have checked it by hand and discovered I cannot turn it. So next step will be to adjust it just like I adjusted the top stabiliser. (I have neither read anywhere in this forum nor in the Predator manual about adjustment of this link. But very obviously it is adjustable.) I have no idea if this will reveal any tension which could cause the vibration I have, but we will see.