Get XiED(tm)! Performance Parts

Don't let the Harley heat monster ruin your riding.
Reduce  Engine Surging
Improve Throttle Response
Reduce Engine Ping


HD 2007/2008 Engines

High Heat on 2007/08 HD engines

HD 2007/08 Performance Recommendations

Cool your exhaust temperature with the Wide Band O2 upgrade for 2007/08 HD

Harley Camshaft Specification Tables

HD Twin Cam Engine Builds
TC 128 HP 95 CID
TC 100HP Street Engine

The basics of Fuel Injection explained

Rammer Performance Air Cleaners
TC Performance Heads 100+HP

Pro Tuning on a Shade Tree Budget


Rear Belt Drive Adjustment

Performance and Technical information on the rear belt drive for Harley-Davidson motorcycles.
Belt Drive Adjustment for Big Twins

belt_adjust_dyna.jpg (17473 bytes)

bulletSet belt tension a the tightest rotational point on the sprockets.
bulletThe adjustments should be done when the bike is cold.
bulletThe adjustments should be made with the weight of a rider on the bike.

1. At the lower strand, position "A", mid-way between transmission sprocket and rear wheel sprocket, apply 10 Ibs. of upward force on lower span of rear belt. Harley-Davidson has a BELT TENSION GAUGE (Part No. HD-35381) to help.

2. Measure belt deflection "B" several times, each time with belt moved (by rotating rear wheel) to a different position on sprockets. With sprockets rotated to tightest belt posi-tion, belt deflection "B" (measured at position "A") should be 5/16-3/8 in.


1. Loosen rear axle nuts.

2. Measure each side from the flat to the end of the swingarm, to be sure rear axle is correctly located.

belt_adjust_measure.jpg (12914 bytes)

3. Turn axle adjuster nuts (metric) on each side of swing-arm to adjust belt deflection.

a. Turn clockwise to decrease deflection (increase tension).
b. Turn counterclockwise to increase belt deflection (decrease tension).

Turn each adjuster nut exactly the same number of turns to maintain rear wheel alignment.

5. Tighten axle nut  to 60-65 ft-lbs.


Keep dirt, grease, oil, and debris off the belt and sprockets. Clean the belt with a rag which is slightly damp with light cleaning agent.

All belts must be handled carefully to prevent bending stress. The belt must never be formed into a loop smaller than 5 inches in diameter and never be bent backwards. Sharp bending can weaken the belt and lead to premature failure. Old belts that are taken off a bike during repairs must be reinstalled so they rotate the same direction.

Tricks of the trade

With a high horsepower engine, it is better to have the belt a little tight rather than loose. A loose belt will break much more readily than a tight one. Most people do not tighten the belt to its proper tension. If you plan on "racing" or hot rodding your bike, invest in a Harley-Davidson BELT TENSION GAUGE (Part No. HD-35381).


Table of Contents
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Modification, Installation, Maintenance and Tuning Index  will help you find most of the information you want on one page.

How to get Professional Tuning Results at home
Testing the Innovate Motorsport LM-1 portable air fuel meter

Profession Tuning on a Shade Tree Budget

Veypor VR2 Data Logger and Instrument Panel
Video Installation and Demo
Purchase VR2

Engine Performance
How to Build a
TC96 2007 Engines
TC88 70HP Stage1  
TC95 128HP Stage 3
TC95 100HP Street
TC96 2007 Stage 1/2
EVO 64 HP Stage 1
EVO 74 HP Stage 2
EVO 82 HP Stage 3
EVO 95 HP Stage 3
883 to 1200 Upgrade
Shovelhead Modifications

New EFI for EVO and TC

Performance Gallery
Horsepower Gallery
Evolution 80
Twin Cam 88/95
Evolution Unlimited
Sportster Unlimited
Drag Strip Gallery
Land Speed Racing Gallery
CV Carburetor
Modifying the CV carb
Tuning a CV carb
Selecting a cam
Install a TC 88/95 cam
Install a Big Twin cam
Install Sportster cams

Camshaft Specifications
Twin Cam

Exhaust Systems
EVO Exhaust Testing
TC Exhaust Testing
Khrome Werks AR100 test
Making Drag Pipes Work

Shop Manual
Carburetor Troubleshooting
Finding Manifold Leaks
Cylinder Heads
Pistons and Cylinders
Belt Drive
Shop Manual Appendix
$20 Bike Lift
Plug Wires
Spark Plugs
Engine Tuning
Nitrous Oxide
Motor Oil
Stutter Box
General Information
WEB Links
Buy Books and Manuals
Performance Calculations
Estimate Horsepower
Estimate 1/4 Mile Time
Estimate Top Speed

Engine Displacement
Exhaust Length
Gear Ratios
Air Density

The Nightrider Diaries
The ramblings of a genius a, a madman and something in between.

Where is Sifton Cams?

Autocom Active-7 tested

Harley-Davidson EFI
-EFI basics explained
-EFI modifications explained

183 HP, 2 carbs, 2680cc

Copyright 1997-2006  Stephen Mullen, Oldsmar, FL -+-