hey guys,just finished a top end rebuild on my 86 FLT and decided to upgrade to an ev27 .now i've noticed more vibes from 2200 -2800 rpms,,it starts and idles great, but no longer can I ride it below 3000.Is it the cam or something else to look at? I've got true duals,10-1 wisecos ,s&s super E and an ultima ignition set at curve #1.Any thoughts ?Thanks

 

You need to pull that module back to #3 with 10-1 and EV27 for now, it is detonating right now for sure on #1, doubt if that is your problem but it needs to be done or going to damage a piston.

I believe you have a ignition problem unable to fire the cylinders in the full load area and less of a load in the 3000 range runs ok, those Ultima coils are a crap shoot if you used it with a kit. Would target a coil, plug wires or wire connections because low voltage can do it to. Other than that a compression test is always a good thing, 15 minutes can save days of head scratching.

 

I agree with Bagger. Curve 2 at best... What jetting do you have in the S&S?

 

ok, what do you mean.. "Can no longer ride it below 3000" ? when you went to the Weiscos, you move the balance factor a little, and that will also determine where the Foot feel*( floorboard/foot pegs etc ) of the vibrations are at in a certain givin rpm range.

Is the vibration in the seat area? real fast ?

make damn sure you have the motor mounts tight.

rpm range vibrations can move according to balance percentages.
that range separation can be anywhere from 1200 rpm to around 1500 rpm...example. ( every 1200 rpm 12/24/3600 rpm or 13/14/1500 rpm x's 2 ) it varies and not always an exact science cause of balance factor in the flywheels..

is it so bad that the really numbing fast vibration is what you are feeling... ?

that range of harmonic balance vibrations/static balance vibrations can move around 200-400 rpm and depending on how well the flywheels were balanced and trued to begin with makes a difference too.

 

72 and 28 int.

 

More in the bars,I've got 900 miles since top end is done

 

That changes things, when said you can't ride in that range thinking engine misfire.

Need to go back over things you touched, the engine should actually run smoother being more efficient. Check top engine mount, check for the exhaust for floating, check lower mount for a failure even tho you didn't touch it.

 

Ok, let me be more specific,
Top end rebuild included new rings on existing 10-1 wisecos
Added an EV27 from stock cam
replaced Crane Hi 4 with ultima ignition
Added true duals after finding cracked Y pipe
new s&s hydraulic lifters
had heads cleaned up w/new seals

Vibration isn't terrible just more noticeable between 2000-2800rpms than it was before rebuild
I guess i'll try #2 on the ignition to start,just wondering if this is inherent due to the new cam

 

One other note :engine no longer pings as it did at times before the rebuild

 

Several of us run or have ran a engine at 10-1 with a 40 intake closing cam and a 2000I ignition, EV27 is a 38 intake closing and #2 is the fastest advance usable, I ran a #3 loaded in hot weather. Your stock cam was a 38 but duration was itty bitty restricting cylinder fill with fuel to fill a 10-1 compression, really surprised it worked.

Check those TD's for floating at the rear supports, the vibration will go to the engine, top engine mount, frame, handlebars.