Started with stock TC88 in a 2006 Road King Custom with 55k on the odo.<br />We massaged the twin cam stock heads, Andrews 26G, S&S Lifters, Crane Adjustable Pushrods, S&S Cam Gear drive in a Delkron Backing Plate, Feuling Oil Pressure Relief Spring and Piston, stock headers running into the 2006 Screaming Eagle Slip-ons and tuned the fuel delivery with a Power Commander 20% + across the entire RPM range. Way more power than I was expecting. Clutch slipping so we rebuilt with extra clutch disc's and heavy duty spring - still won't hold! Installing a Barnett High Performance Assembly soon. Excited to see the dynamometer report when we can get all that power to the ground. Super happy.
S&S Cycle Crankcases 4-1/8" Wrinkle Black - Harley Twin Cam 88A 1999-2006 (Excl. 2006 Dyna)
About S&S Cycle
S&S Cycle has built American V-twin performance parts in Viola, Wisconsin since 1958 — flywheels, carburetors, cams, cylinder heads and complete crate engines. When a Harley owner talks about a 124, a 128 or a 131 build, they are usually talking about S&S. Few names carry more weight with engine builders in this space.
Build the ultimate performance Twin Cam engine with S&S Cycle crankcases, specifically designed for 1999-2006 Harley Twin Cam 88A engines. These crankcases feature reinforced construction and larger bearing surfaces, providing the robust foundation needed to handle the demands of high-performance V-twin builds. Finished in a distinctive 4-1/8" wrinkle black, they also offer clearances for aggressive cam profiles.
Why riders pick this
- Reinforced construction for high-performance
- Large cam chest for up to .675" cam lift
- Timken-style sprocket shaft bearings included
- Oversized front motor mount for rigidity
- Wrinkle black finish for custom aesthetics
The crankcase is the backbone of your Harley-Davidson engine, and for serious performance, an upgrade to S&S Cycle crankcases is a must. These units are cast with a 4-1/8" bore and finished in wrinkle black, providing both strength and a custom aesthetic. They are engineered to eliminate common Twin Cam issues, featuring a large cam chest that accommodates cam profiles up to .675" lift without additional clearancing, and Timken-style sprocket shaft bearings for superior durability. The oversized front motor mount further enhances overall engine rigidity.
Engineered for High-Performance Twin Cam Builds
- S&S breather reed valve to prevent oil carry-over
- Large cam chest clears up to .675" cam lift
- Durable Timken-style sprocket shaft bearings
- Extra-large front motor mount for increased strength
- Includes pinion and bearing hardware for a complete assembly
The Foundation for Power
These S&S Cycle crankcases are more than just replacement parts; they are a significant upgrade designed to unlock greater performance potential from your Twin Cam 88A engine. The enhanced structural integrity and thoughtful design features mean your engine can reliably produce more horsepower and torque. Perfect for riders planning a substantial engine build, these crankcases provide the reliability and performance S&S Cycle is known for. Note that these are not compatible with 2006 Dyna models.
Specifications
- Brand: S&S Cycle
- Manufacturer Part #: 31-0178A
- Finish: Wrinkle black
- Stud Pattern: 4-1/8"
- Weight: 40 lb
- Category: Engine Components / Crankshafts
Common questions
Does this fit my 2006 Dyna?
No, this S&S Cycle crankcase is specifically not compatible with 2006 Dyna models. It is designed for 1999-2006 Harley Twin Cam 88A engines, excluding 2006 Dyna.
What's included in the kit?
The kit includes the S&S crankcase, S&S breather reed valve, pinion, Timken bearing, and all necessary mounting hardware to complete the assembly.
Do I need to bore these crankcases for larger cylinders?
These crankcases come with a 4-1/8" bore. If you plan to run larger cylinders, you may need to confirm compatibility and potentially bore them further, depending on your cylinder choice.
Ordering from Vtwinbikers
- Brand new, sourced through authorized US distribution — never used, never grey-market.
- Not sure it fits? Use Shop by Bike to filter by your year and model, or email us and we will confirm before you order.
- Harley-Davidson and Indian Motorcycle is all we do, so you are talking to people who ride what you ride.
| BRAND | S&S Cycle |
| TYPE | Crankshafts |
| SKU | T14-663804 |
| WEIGHT | 40.0 lb |
Love everything about this upgrade for my twin cam 88
Real nice set. Very complete.
I haven't installed it yet but I was impressed with how fast it came in on standard shipping. These people wasn't messing around. Hope to have on soon so I can try it out. I know it will be great tho. I've never been let down by an s&s product
Went from 72 hp to 86.5 hp. Big difference very happy!
Just an update on my last review,<br />I'm so pleased with how much power this kit produces, on a 2000 FLHTCUI twin cam 88 that is now a twin cam 97-10.0:1 compression roller rockers adjustable push rods and a 3 angle valve job and some pocket porting done with STOCK CAMS, and a dyno jet tuner, let's just say even in 5th gear I have no need to down shift ridding 2up with two heavy people on it going from about 30 mph back up to 55+ mph like a breeze and as of now I have about 500 miles on the kit and love it. And I'm going to go with the 551g gear drive came kit to get the max power out of this kit