I've recently seen a bike advertised as fitted with a "Race Brace" . This doesn't turn up anything on ebay but I DID find something described as a "Torque Arm"

So, I'm guessing that the Screaming Eagle range includes something designed to stabilise the gearbox relative to the engine?

I know about Torque arms or plates, they are common in vintage racing, but do they serve any useful purpose in the Evo Harley world? Also, do they involve a complete transmission stripdown?

 

The purpose of the torque arm is to stabilize the connection between the engine and transmission one the right side on rubber mount setup. Evo motors have the rear engine mount pretty much the same as shovels / pans / knuckles / flatheads etc. It's a pair of vertical bolts to a horizontal flat surface where the motor sits when solid mounted to a frame. When HD decided to rubber mount the drivetrain, they simply designed a tranny case to fit underneath those holes. This works OK for motors that don't make much HP and are driven normally. It becomes an issue when the joint can shift since the forces are in shear. The connection can work loose.. The left side has the primary case to stabilize the left side. The brace on the right stabilizes interface the other side between the motor and tranny..

Twin Cams and M8s use a 4 horizontal bolt / flat vertical surface to correct this issue.

 

OK, understood. So it is fitted externally and what, you dismantle the right side exhaust to get access? Does it fit all evo motors?



Another ebay pic shows that it requires extended bolts

 

I've not used these as I'm have more experience with EVO softails. Google up "screaming eagle racebrace" and you get more than I know..

 

Originally made by Carlini, known as a "Torque Arm". https://www.carlinidesign.com/produc...s/torque-arms/

 

I do find it interesting that Carlini does make one for an EVO softail.. Motor bolts directly to the frame.. Maybe if the motor is making over 200 hp?

 

Back in the mid or late 90's i had a screaming eagle race brace on my old 93 dyna. It cracked in two. Inside corner between transmission side and engine nose cone side was a sharp corner, no radius. Cracked there all the way down. Not a high horsepower bike either. Had some work done but I doubt it made more than 75-80hp. Took it off and nothing else ever broke there.
The Carlini torque arms had a radius in that corner. At least back in those days. The race brace I had did not