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SCREAMIN' EAGLE PRO XL PERFORMANCE CYLINDER HEADS
J041862006-09-25
GENERAL
Kit Number
16677-07
Models
This kit fits This kit fits 2007-later XL 1200 model motorcycles.
Additional Parts Required
This kit requires the separate purchase of Perfect Fit Pushrod Kit 18424-06, which is available from a Harley-Davidson dealer.
Top End Overhaul Gasket Kit 17049-04 must also be purchased separately and is available from a Harley-Davidson dealer.
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.
Recommended Parts
H-D recommends the use of Exhaust Flange (65328-83) to aid in exhaust headpipe re-installation. The headpipes should also be disassembled from the mufflers when attempting to re-assemble the exhaust system to the engine and motorcycle. The exhaust flanges can be purchased from a Harley-Davidson dealer.
Kit Contents
See Figure 1 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.
Refer to ENGINE section of Service Manual for all removal/disassembly and assembly/installation procedures.
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 on the new cylinder heads have an installed spring height of 1.895 in. (48.1 mm), which equals 184 lbs (83.6 kg) of seat pressure.
  1. Remove the existing cylinder head assemblies.
  • To increase seat pressure, place shims 18224-98 (0.015 in.) or 18225-98 (0.030 in.) under lower spring collars. Each 0.015 in. (0.38 mm) spring height reduction equals 3.8 lbs (1.7 kg) more seat pressure. Shim to the desired seat pressure by placing shims under the lower collar, but maintain a minimum of 0.70 in. (17.78 mm) travel to coil bind.
  • To decrease seat pressure, machine the surface of the cylinder heads in the area under the lower spring collar. Every 0.015 in. (0.38 mm) increase in spring height equals 3.8 lbs (1.7 kg) less seat pressure. Machine to the desired seat pressure by machining the spring pockets in the cylinder heads, but maintain a minimum of 0.70 in. (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. To change installed valve spring height (seat pressure):
    1. Compress valve springs and remove valve collar retainers, upper collars, springs, and lower collars/ valve seals on all four valves.
    2. Use shims or machine the cylinder heads as required to obtain desired seat pressure. Install lower valve spring collars (without valve seals), valve springs, upper collars, and collar keys. Check installed spring height.
    3. If spring heights still do not match, repeat Steps 2a and 2b above as necessary to reach the desired installed spring height, again without installing valve seals.
    4. When all spring heights match, remove valve collar retainers, collars and springs. Install using new lower collars/valve seals 18016-03 purchased separately. Assemble the cylinder head assemblies.
  2. Install new cylinder heads from kit using new gaskets from Top End Overhaul Gasket Kit purchased separately.
  3. Check engine for proper installation and operation.
SERVICE PARTS
Figure 1. Service Parts: Screamin' Eagle Pro XL Performance Cylinder Heads
Table 1. Service Parts: Screamin' Eagle Pro XL Performance Cylinder Heads
Kit
Item
Description (Quantity)
Part Number
Kit 16677-07
Black
1
Cylinder head assembly, rear (not shown, includes items 3 through 9)
16657-07
Cylinder head assembly, front (shown, includes items 3 through 11)
16655-07
2
  • Cylinder head (machined, with items B, C and D installed)
Not Sold Separately
3
  • Collar, valve spring, upper (4) (available only as part of item A)
Not Sold Separately
4
  • Collar and valve guide seal, valve spring, lower (4) (part of item A)
18016-03
5
  • Stud, exhaust port (4)
16715-83
6
  • Intake valve (2)
18010-05
7
  • Exhaust valve (2)
18028-05
8
  • Retainer, valve collar (8) (also included with item A)
18260-02
9
  • Valve spring (4) (available only as part of item A)
Not Sold Separately
10
  • Medallion, Screamin' Eagle (front cylinder head only)
29508-05
11
  • Screw, button head, Torx (2) (front cylinder head only)
94634-99
The following items come installed in the cylinder heads, but are also available separately:
A
Screamin' Eagle Valve Spring Kit
18013-03A
B
Valve seat, intake
18020-07
C
Valve seat, exhaust
18011-86
D
Valve guide, intake and exhaust
16461-02