Harley Davidson XR 1986 bulletin Manual

XR-1000 HIGH PERFORMANCE DATA FOR CLOSED

Chamber

Comb

Vol

.

.

+

CIRCUIT RACING

General

This bulletin provides specification information and other data for
improved performance of the XR-1000 motorcycle for closed circuit
racing.

NOTE

Use of any of the Harley-Davidson part numbers listed in this
bulletin voids all warranty.

Table of Contents

SUBJECT PAGE

Engine 1-4
Transmission & Shifter 4-5
Clutch 6-8
Gearing 9
Ignition and Spark Plugs 9-10
Carburetion 11
Chassis 11
Exhaust Pipes 11
Fuel and Oil 12
Suppliers 12

Engine

The stock XR-1000 engine will produce approximately 71 HP at
5600 RPM. In modified condition, with "E" cams, racing
megaphones and high compression pistons installed, the engine
will produce approximately 93 HP at 6400 RPM

Max RPM stock Engine 6200
Max. RPM Modified Engine 7200

HIGH COMPRESSION PISTONS

DISPLACE (cc)

PART # BORE PER CYLINDER

22600-83R Std. 499
22603-83R +0.030 508
22605-83R +0.060 518

22606-83R +0.070 521

Piston to cylinder wall clearance: 0.0035 0.0045 in.
A break-in distance of 50 miles is required when new pistons are

installed and cylinder is bored for 0.0035 clearance.

COMPRESSION RATIO

Do not exceed 10.5:1. The formula for calculating the compression
ratio is:

ChamberCombVolCylVol

CR

=

To measure combustion chamber volume, do the followings

1. Coat cylinder wall with general-purpose grease. (This will
prevent the oil, used to measure combustion chamber
volume, from leaking past the upper piston ring.)

2. Install cylinder head and turn engine so piston is at top dead
center (TDC) and both valves closed.

3. Tilt engine so spark plug hole is level.

4. Fill a beaker, having cubic centimeter (cc) graduations, with
75cc of light oil.

5. Place a small funnel in spark plug hole and fill combustion
chamber with oil from the beaker. Continue filling until oil
covers bottom two threads of spark plug hole.

6. Check the amount of oil remaining in beaker and subtract that
amount from the original 75cc. The difference equals the
combustion chamber volume-

EXAMPLE:

75cc Oil in beaker

- 22cc Oil remaining in beaker
53cc = Volume of combustion chamber

Insert the above volume and the cylinder volume given with
high compression pistons into the compression ratio (CR)
formula:

...

1:4.10

=

==

+

CR

NOTE

4.10

1

552

53

53499

53

=

CR

INTAKE AND EXHAUST PORTS

Although the XR-1000 ports are very efficient, additional porting
work can be done. Suppliers recommended are Branch
Flowmetrics or C. R. Axtell. Supplier’s addresses and phone
numbers are listed on the last page of this bulletin.

FLYWHEELS

Before assembling the flywheel, extreme care must be taken in the
cleaning of the tapers and the threads. After parts are cleaned in
solvent it is necessary that the deposits are washed away with
detergent and then rinsed in clean water. Clean tapers must not be
touched with the fingers

FLYWHEELS AND SHAFTS

Torque to 120 ft-Ibs. Leave them set overnight or a minimum of
four (4) hours. (Use grease sparingly on the threads while keeping
the tapers clean) When it is time to retorque, remove nuts, clean
thread (see above), and add Loctite.

If the procedures specify Loctite, use Loctite 620 RETAINING
COMPOUND.

Order part number 25480-83R for a complete set of "E” cams.
"E" Cam Timing at 0.060 in. Tappet Lift is as follows:
Intake opens at 33° BTDC

Intake closes at 54° ABDC
Exhaust opens at 65° BBDC
Exhaust closes at 24° ATDC
Full tappet lift 0.300 in.
Rocker arm ratio 1.48
Valve Lash:
"E” Cams with muffler 0.012 in.
'”E" Cams with open megs 0.006 in.

CAUTION

Valve to valve clearance (valves on seat) should measure

0.180 in. minimum.

Be sure to check clearance between cam lobes and the crankcase
(front intake and rear exhaust only).
See Figure 1 Install set screws in cam cover and cam bushing, as
bushings may tend to work their way out.

Locate in bushing of number 1, 2, 3 and 4 camshaft and pinion
shaft.

FLYWHEELS AND CRANKPIN

Torque to 100 ft-Ibs and true assembly (Use grease sparingly on
the threads while keeping the tapers clean.) Next torque to 175 ft –
Ibs, followed by the same waiting period and retorquing as for
flywheels and shafts. Recheck runout.

NOTES
Loctite as well as grease serves as a lubricant during the
tightening.

W-D 40 must not be used for lubricant as it will spread to the
tapers.

Solvents leave a powdery deposit, which serves as a lubricant.
If time does not permit the retorquing procedure to be followed, all

nuts should be assembled with Loctite immediately.
/f Loctite /s used on tapers take care that none is spilled into the

rod bearing (parts cannot be retorqued.)
Harley Davidson flywheels are made of cast iron. Forged steel

flywheels are available from S & S Cycle

CAM SHAFTS

For best performance use Harley-Davidson “E” cams.

Figure 1. Retaining Cam Cover Bushings

8-32 x 0.375 in. set screw

CYLINDER STUDS AND NUTS

Be sure the cylinder head nuts are torqued to 30 ft-Ibs.

CONNECTING RODS

Do not polish connecting rods, they are shot peened and polishing
will destroy their properties.

PISTON RINGS

End gap top and second compression ring: 0.012-0.014 in.
Before installing the cylinders and pistons, make sure that the ring
grooves for the compression rings, as well as the oil rings, are
machined deep enough.

When rings are pushed against the bottom of the ring groove ring
must be a minimum of 0.015 in. below outside diameter of the
piston.

OILING SYSTEM See Figure 2 Add baffle plate to crankcase
sump as shown.

Figure 2. Oil System Modifications

Change return oil line from rear cylinder head to drain directly into
sump For this a 1/8 in. taper pipe thread hose fitting has to he
installed in the right crankcase (see bottom view of Figure 2).
Locate this fitting with engine mounted in the frame.

CYLINDER BASE GASKET

Eliminate the gasket use Dow Corning 732 silicone sealant.

Proper placement will be above the lower frame tube and behind
the vertical crankcase boss for oil pick-up hole.

To reduce oil flow to the connecting rod bearing a restrictor
should be pressed into the pinion shaft One way to make this
would be to machine the thread off a carburetor main jet (A main
jet from an MX, SS or SX carburetor may have the following
dimensions.)

Pinion shaft hole size 0.19 ± 0.02 in.
Restrictor hole size 0.090 in.

Transmission

In road racing 1st 2nd and 3rd gears are used more frequently
than in normal street use The bushing in the clutch gear is
subjected to higher speeds and must be packed in grease or in its
place a needle bearing (Torrington #B1010) can be installed. See
Figure 3. To allow use of the needle bearing the mainshaft must
be ground to dimensions shown Remove stock bushing and press
needle bearing into clutch gear as shown.

Figure 3. Transmission Modification