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

Motorcycle Performance Guide

Calculate Gear Ratios

This program calculates the gear ratios of a motorcycle. The primary drive ratio and overall ratios for each gear are all calculated. Just enter the data in the white boxes below, then click the "Calculate" Button. Pressing the "Reset" button loads the default values into the form.

Engine Sprocket
Clutch Sprocket
Transmission Sprocket
Rear Wheel Sprocket

Primary Drive Ratio ( Engine to Transmission ) is calculated
Final Drive Ratio ( Transmission to Rear wheel ) is calculated
Overall Drive Ratio is calculated

Enter the Transmission ratio   Computed Overall Ratio  
1st gear  
2nd gear  
3rd gear  
4th gear  
5th gear Use a value of 1 if the bike does not have the gear
6th gear  

The reset values displayed are from a 1994 FXDL Harley-Davidson Dyna Low Rider. All late model Harley Big Twin models have similar. The Rear Wheel Sprocket can vary, with belt drive models using a 61, 65 or 70 tooth sprocket. Below is a table of typical values for late model Harley-Davidson motorcycles.

Ratios listed for all 2007 model HD's are overall ratios.

Make Model Engine Sprocket Clutch Sprocket Trans Sprocket Rear Wheel Sprocket 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th
34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
FLS models
34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
07-later Japanese 34 46 32 64 9.030 6.226 4.630 3.807 3.179 2.706
2008 HD EVO 1200 Sportster 38 57     9.315 6.653 4.948 4.102 3.517  
2008 HD EVO 883 Sportster 34 57     10.782 7.702 5.728 4.748 4.071  
HD FXDL Domestic 24 37 32 70 3.24 2.21 1.60 1.23 1.00  
HD FXDL Export 24 37 32 65 3.24 2.21 1.60 1.23 1.00  
HD FXDL Australia 24 37 32 61 3.24 2.21 1.60 1.23 1.00  
HD Drive Kit 40035-00
1996 HD EVO 883 Sportster 35 56 27 61 2.687 1.97 1.434 1.79 1.00  
1996 HD EVO 1200 Sportster 35 56 29 61 2.687 1.97 1.434 1.79 1.00  


Table of Contents
Search the site 
Nightrider COPYRIGHT

Ask us a Question

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 -+-