ARP Derby Cover/Clutch Inspection Cover Bolt Kit
- These high-quality bolts will replace your low-grade factory bolts
- 12 Point bolts in black or polished stainless to match most derby covers (will not fit recessed holes but heads can be machined down)
- Made in the USA
- Manufactured to Imzz Elite exact specifications
Fits all years and models of Twin Cam
(Bolt heads may not fit with CVO and some bagger model derby covers. Heads will need to be machined down to fit in recess)
Find more ARP Hardware kits for your Harley HERE.
What is a Black Oxide finish?
Black oxide or blackening is a conversion coating for ferrous materials, stainless steel, copper and copper based alloys, zinc, powdered metals, and silver solder. It is used to add corrosion resistance, for appearance and to minimize light reflection. One of its advantages over other coatings is its minimal buildup; the blacking process creates a layer only about a micrometre thick.
Why are my new bolts oily?
That oil keeps them from corroding and keeps them looking new! You’re a biker…you can’t be afraid to get your hands dirty. (If you are, trade your Harley in for Vespa.) Hot baths of sodium hydroxide, nitrates, and nitrites (at 286 °F) are used to convert the surface of the material into magnetite (Fe3O4). To achieve maximal corrosion resistance the black oxide must be impregnated with oil or wax. Once the process of dipping is completed the top layer of the fastener is porous and a layer of oil is applied, similar to a pickling process. The oil seeps into the material adding that extra corrosion resistance to rust.
Will they rust?
Black Oxide adds a layer of corrosion and abrasion resistance to fasteners. Like any material, black oxide treated fasteners can rust in the right environments. It will depend on if the fastener is damaged or marred, the type of metal with the black oxide treatment and environmental conditions. In high heat environments, the oil residue that stays on the fasteners will begin to turn brown. Many users find their bolts look like they rust prematurely when really, the oil is just changing colors. See the next Q&A to learn how to bring them back to looking new if they begin to show rust.
Do they require maintenance?
Like any treated, chromed or painted surface, they do require some maintenance. It’s simple and takes only a few minutes! To keep your black oxide hardware looking good and new on your bike, they must be oiled. We recommend spraying WD-40 on a rag and wiping the surface of the hardware whenever you clean your bike. Don’t wait for them to look bad before doing something. A quick swipe with WD-40 every now and then will keep them looking brand new and prevent corrosion. We use Silikroil around the shop which we prefer over WD-40. You can find it on Amazon. In hot, rainy or humid environments, they may require more frequent maintenance.