SCREAMIN' EAGLE TWIN CAM HIGH-TORQUE COMBUSTION CHAMBER CYLINDER HEAD KIT

J034002006-05-02

GENERAL

Kit Number

Kit 16926-99B, with a pair of Silver cylinder heads

Kit 16933-99B, with a pair of Black cylinder heads

Models

These kits fit 2002-2005 EFI Touring, 2004-2005 EFI Dyna^™, and 2001-2005 EFI Softail^®, and 1999-2006 Carbureted model motorcycles.

Additional Parts Required

These heads MUST be used with matching Screamin' Eagle Twin Cam High-Torque Combustion Chamber (HTCC) forged pistons.

On all models adjustable pushrods (Part Number 17997-99A) must be used.

On all models, a Top End Overhaul Gasket Kit (Part Number 17052-99B) must be used.

WARNING

Rider and passenger safety depend upon the correct installation of this kit. Use the appropriate service manual procedures. If the procedure is not within your capabilities or you do not have the correct tools, have a Harley-Davidson dealer perform the installation. Improper installation of this kit could result in death or serious injury. (00333b)

NOTE

This instruction sheet references Service Manual information. A Service Manual for your model motorcycle is required for this installation and is available from a Harley-Davidson Dealer.

These heads require the use of 12mm spark plugs. We recommend Screamin' Eagle Performance Spark Plugs, Part Number 32321-91 (pair of two).

All of the above items must be purchased separately and are available from a Harley-Davidson Dealer.

Kit Contents

See Figure 2 and Table 1.

INSTALLATION

NOTE

These kits are intended for High Performance or Racing applications only. These engine-related performance parts are not legal for sale or use on pollution-controlled motor vehicles. This kit may reduce or void the limited vehicle warranty. Engine-related performance parts are intended FOR THE EXPERIENCED RIDER ONLY.

Due to the increased compression ratio, gasoline with a rating of at least 91 Octane must be used. The Octane Rating is usually displayed on the gas pump.

NOTICE

Do not exceed the maximum safe RPM specified below under any conditions. Exceeding the maximum safe engine RPM can result in equipment damage. (00248a)

NOTE

The valve springs in these cylinder head assemblies work with cams with up to .575 inch (14.61 mm) lift, and up to 6500 rpm.

Remove the existing cylinder head assemblies. Refer to the ENGINE section of the Service Manual for all removal and disassembly procedures.

NOTE

It is important to check valve-to-piston clearance as described in the following steps. We recommend that this inspection be performed by a Harley-Davidson Dealer.

Valves must be properly adjusted to zero valve lash when claying pistons.

Apply a 1/8 inch (3.2 mm) thick layer of clay to the crowns of both pistons (in the areas where the valves meet the pistons).

Install the new cylinder heads from this kit per the Service Manual procedures, using the new gaskets from the Top End Overhaul Gasket Kit (purchased separately). Assemble the heads and valve train, and tighten the internal-threaded cylinder screws to the torque specifications listed in the Service Manual.

Turn the engine (by hand) through two complete revolutions.

Remove the heads and measure the clay at its thinnest point.

NOTE

Clay must measure 0.080 inch (2.03 mm) at the thinnest point. If this measurement does not meet the minimum thickness, the depth of the valve notches must be increased; however, the depth of the notches must not exceed 0.135 inch (3.43 mm).
Since oversized valves are used, radial clearance should also be checked. Radial clearance of 0.050 inch (1.27 mm) is recommended.

NOTE

The valve springs on these cylinder heads have an installed spring height of 1.830 inch (46.48 mm), which equals 165 lbs. (74.8 kg) of seat pressure.

Seat pressure can be increased by placing shims (Part Number 18224-98 [.015 inch] or 18225-98 [.030 inch]) under the lower spring collars. Every .015 inch (0.38 mm) reduction in spring height equals 7 lbs. (3.2 kg) more of seat pressure. Shim to the desired seat pressure by placing shims under the lower collar, but maintain a minimum of 0.70 inch (17.78 mm) travel to coil bind.
Seat pressure can be decreased by machining the surface of the cylinder heads in the area under the valve spring lower collar. Every .015 inch (0.38 mm) increase in spring height equals 7 lbs. (3.2 kg) less of seat pressure. Machine to the desired seat pressure by machining the spring pockets in the cylinder heads, but maintain a minimum of 0.70 inch (17.78 mm) travel to coil bind.

For constant operation at extreme RPMs, all four valve springs should be checked for matched, installed heights.

1	Upper collar
2	Lower collar
3	1.830 inch (46.48 mm) installed spring height/ 165 lbs. (74.8 kg) spring pressure.
4	Free travel should be at least 0.080 inch (2.03 mm) greater than maximum valve lift.

Figure 1. Valve Spring Travel

To change installed valve spring height (seat pressure):

a. Compress the valve springs and remove the valve collar retainers, upper collars, springs, valve seals, and lower collars on all four valves.

b. See Figure 1. Use shims or machine the cylinder heads as required to obtain the desired seat pressure (see notes above). Re-install the lower valve spring collars, valve springs (do not install valve seals at this time), upper collars, and collar keys. Check the installed spring height.

c. If spring heights still do not match, repeat steps a and b above as necessary to reach the desired installed spring height, again without installing valve seals.

d. When the spring heights have all been matched, remove the valve collar retainers, upper collars, springs and lower collars. Re-install using new valve seals, Part Number 18046-98 (purchased separately). Re-assemble the cylinder heads following Service Manual procedures.

e. Because of the large diameter of the springs in this kit, there may be slight interference between the spring and the rocker box. If interference is detected, the clearance in the rocker box bolts may allow enough movement to gain clearance. If not, it may be necessary to remove a small amount of material from the rocker box.

Re-install the new cylinder heads. Refer to the ENGINE section of the Service Manual for all assembly procedures.

Check the assembled engine for proper installation and operation.

NOTE

The compression release plug can be removed for installation of a Screamin' Eagle Compression Release Kit (Part Number 29298-02).

SERVICE PARTS

1	Cylinder head assembly (2) (includes items 2 through 11)
2	Cylinder head (2) (includes items A, B, C and D)
3	Valve spring upper collar (4)
4	Valve spring lower collar (4)
5	Exhaust port stud (4)
6	Intake valve (2)
7	Exhaust valve (2)
8	Valve seal (4)
9	Valve spring unit (4)
10	Valve collar retainer (8)
11	Compression release plug (2)

Figure 2. High-Torque Combustion Chamber Cylinder Heads, Kit J03400

Table 1. Service Parts Table

Kit	Item	Description (Quantity)	Part Number
Kit 16926-99B Silver	1a	Cylinder head assembly, rear (includes Items 2 through 11)	16924-99B
Kit 16926-99B Silver	1b	Cylinder head assembly, front (includes Items 2 through 11)	16923-99B
Kit 16933-99B Black	1a	Cylinder head assembly, rear (includes Items 2 through 11)	16930-99B
Kit 16933-99B Black	1b	Cylinder head assembly, front (includes Items 2 through 11)	16929-99B
	2	Cylinder head (machined, with items A, B, C and D installed)	Not sold separately
	3	Collar, valve spring, upper (4)	18269-00
	4	Collar, valve spring, lower (4)	18270-00
	5	Stud, exhaust port (4)	16715-83
	6	Intake valve (2)	18177-99
	7	Exhaust valve (2)	18175-99
	8	Seal, valve (4)	18046-98
	9	Valve spring unit (4)	18272-00
	10	Retainer, valve collar (8)	18271-00
	11	Plug, compression release (2)	32069-02
The following service items are available separately:
	A	Valve seat, intake	18174-99
	B	Valve seat, exhaust	18173-99
	C	Valve guide, intake (for service)
		(+ 0.003 in)	18158-05
		(+ 0.002 in)	18156-05
		(+ 0.001 in)	18154-05
	D	Valve guide, exhaust (for service)
		(+ 0.003 in)	18157-05
		(+ 0.002 in)	18155-05
		(+ 0.001 in)	18153-05