After owning two 1200 Sportsters, I moved up to a 2006 Dyna Lowrider with only 3500 miles on it. My Sportsters were as smooth on deceleration as they were on acceleration. The Dyna vibrates, shakes, and shudders on deceleration in every gear from 2500 RPM to idle. It's not the normal Harley shake or vibration at idle which I love. It actually reverberates the fuel pump, sender unit, and other parts inside the tank!!!

I replaced the motor mounts, did the alignment with a digital inclino-meter, tuned the motor with a PCIII, and replaced the automatic chain tensioner. Nothing helped, so I disassembled the entire primary and checked the inner primary bearing, clutch bearing, compensator bolt, sprocket alignment, and sprocket shaft/mainshaft runout. The crank has .004 runout and the mainshaft has .003 runout. While not great, this is as good as it gets from MOCO.

While examining the compensator assembly, I noticed that the sprocket wobbles on the extension. The spring pack feels weak and has almost no preload. Since the Sportster does not use a compensator, I've concluded that this is the culprit. I've considered going to an enclosed belt drive to eliminate the compensator, heavy chain assembly, and adjuster, but there are none available yet for 2006 and up. BDL says maybe next year?

I won't even ride this bike the way it is, it's beautiful, but rides like sh*t! I can easily remove the spring pack and the compensator cam and TIG weld the extension to the sprocket to create my own 34 tooth sprocket and lose the compensator. I don't know why Harley feels that the 1200 Sportster doesn't need any compensation and the 1450 does. I don't beat on my bikes at all. I don't want to wait for someone to make an enclosed belt drive and don't want a noisy, chattering dry clutch either. (Picky aren't I?)

Does anyone know if the new SE Compensator will work on the 2006 Dyna? The book says 2007 and up only, but unless the sprocket shaft on the 96" is different, it should work. But, I don't even know if that will cure the problem. So, I'm asking for some knowledgeable opinions. Should I compensate or not compensate?

 

WOW is all I can say, good luck in whatever you decide but it sounds like you should just go back to the Sporty's. This was not meant in a bad way but that is why there are so many models, different strokes for different folks.

 

I'm trying to decide the same thing but for a different reason. Looking to go down to a 30T engine sprocket from a 34T on an '07 Dyna. The Evo industries 30T that i'm considering has no compensator. I don't know if this is bad for the crank and bearings or if it adversely effects the vibration level. I'd really like to use this 30T engine sprocket as it is the easiest way to get around the lousy 2.79 gearing that my '07 Dyna has. 2.79 sucks even with the 103 installed.

 

There's someone else on here who welded up one of the new BDL Compensators. It's under another thread. There would have to be less vibration with no compensator over a worn out wobbly one!

 

I'm looking for opinions of a techical nature from other experienced technicians on an abnormal condition. It has nothing to do with model selection.

 

Don't think the comp is your problem. If the spring pack is weak there would be no effect at idle, unless it's ready to fall off. The only time the stock comps actually do anything is in cruise, and that's only with a good spring pack. This is to smooth the ride out and tame the pulses somewhat. Add reasonable power they go solid. The small amount of wobble is there because of clearance on the parts and unless they are totally waisted there will always be some play here. On a 34 tooth dia that could be close to 1/16" at the rim. That in itself should not create much vibration. I'd be checking engine mounting and links and possibly the engine tune itself.
Ron

 

Appreciate the reply. I don't care about smoothness or any of that stuff. Do you think that running an engine sprocket without the compensator is dangerous or hard on the bearings, crank assembly or anything else?

 

Hi Ron,

The mounts have all been changed, links aligned, adjusted, and tight as noted in my original post. I have a PCIII and have tried all the maps I could find for my setup, (Vance and Hines Big Shots, Quiet Baffles, SE Air Cleaner) including a zero map to see how it ran on the stage I flash. The PCIII cures some popping on deceleration and surging/hesitation, but nothing on the vibration. I've seen a dozen other complaints on the various hd forums, all exactly the same as mine, but no one has an answer. My Sportster were carbureted, so I'm not used to the EFI, but if this is how Dynas run normally, Harley coudn't sell one of them!

 

Evolution Industries sells a 30 tooth sprocket and chain to eliminate the compensator and lower the gear ratio. They claim it's their biggest seller....

 

Let's go back to the crank runout. Where did you measure it, as in at the end of the shaft, or in the middle? In order to really see what's happening fast is to run the engine with the outer primary off. Watch the sprocket. In order to have that kind of monterous vibration that thing would have to be seriously visible in shake. If it is, your crank has shifted. To me, the crank is the only thing in there with enough mass to cause serious shaking. Sounds like you did everything else that could be done.
Ron