Anybody running a complete shovelhead engine from S&S? Curious if they vibrate and shake as bad as the factory shovelheads.
depends on the bore and stroke and lift and duration of the cam. All stock shovel heads vibrate because of the torque of a 45 degree crank configuration. dirty
Since they are essentially the same thing, why would it vibrate any differently? I had my 74" balanced (as best you can a V twin), and it does not vibrate that bad until you get north of 4500 or so. But in it's "happy zone", is actually quite smooth. For a rigid mount that is...
-JW
Got to find that zone as JW said. 74 inch is the smoothest running in my opinion.
Right around 3000 on my 80"
I feel my 03 S&S 93" mill vibrates much less than the 74 I pulled out of it but I never had the original apart. Who knows who was in it before I bought it and what kind of havoc has be wreaked ?
There are also other factors. I ditched the compensator and stock clutch, added a Hayden primary tensioner and a spring loaded rear chain tensioner the same time the S&S mill went in. I might as well admit my factory 4 speed is on a basement shelf as well, replaced with a RT 5 inna 4 unit.
Mark, my experience the same, any bike I had that had a custom balanced S&S lower end was smoother than the stock motor before hand. They all vibrate, just that some have very deep harmonics and shudder the bike. Better balanced lower ends stay pretty smooth till upper RPM's. Mostly because they're balanced for mid ROM.
A 74" is smoother because it has a short stroke and extremely heavy flywheels.
I had ridden Hondas and Yamahas quite a bit before I rode my first Shovel. I couldn't believe anyone would ride one of those paint shakers without trying to figure out the problem and get that fixed. Turned out, just business as usual.
Quote from: Burnout on September 02, 2019, 07:16:24 PM
A 74" is smoother because it has a short stroke and extremely heavy flywheels.
makes complete sense
Don't forget, shovelheads were most a 70's AMF thing. Vast tomes written about quantity over quality from those days. Did they even bother balancing them at the factory? How good was the balance job? I think the comments about 74s stock vs. balanced by a competent engine builder speak to that.
-JW
Late 78 the factory got a new Borg Warner balance machine, that was programmed 90° off from where it was supposed to be. Took em a couple months of production to find it. The factory paid the dealers almost two hundred dollars apiece, to put new flywheels in each affected bike. My old boss would balance each original flywheel to specs using the S&S balance setup, and throw the new flywheels into inventory. Ran smoother than the new flywheels, and free inventory to boot!
You will never get a HD to be vibration free from low rpm to peak rpm.
Best that can be done it to put the vibration point where you are not normally riding.
We use S&S Master Balance Tooling to perform that work, and strictly adhere to S&S's guidelines when doing so, with great results.
Most S&S Shovel engines we have experienced are smooth, with the exception of 5" strokes, which have a pulsation, not vibration.