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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

DEWEY'S CUSTOM
Rammer Performance Air Cleaners
TC Performance Heads 100+HP

Pro Tuning on a Shade Tree Budget

   

Stage 1 Modifications
Build a Stage 1 Twin Cam engine

Performance and Technical information on basic modifications to a stock Harley-Davidson Twin Cam motorcycle engine with a CV carburetor.

How to get 10 more horsepower from your stock TC88 engine

One of the first things most people do shortly after they get their new motorcycle is start to modify the engine. In the time honor tradition of Harley-Davidson, the first thing to go on most bikes are the stock mufflers in an effort to improve the sound. This is usually the first in a long list of changes to the engine. Changes to the carburetor and ignition system also rank very high on the first to change list. These changes are done to improve the performance of the bike.

There are many companies out there that are competing for the dollars that Harley owners are willing to spend on their bikes. As an owner, you will be bombarded with a vast array of promises, claims and inaccuracies in an effort to get your money. Reading between the lines on many of the performance claims can be bewildering.

Does the Harley-Davidson world need another stock engine modification article? I decided it does, since the results obtained by the engine upgrades listed here provided significantly better results than those documented by the popular magazines aimed at the V-Twin crowd.

How to build your own Stage One engine

Stage One engines involve no internal changes to the engine. All modifications are made by bolt-on changes to external components on the engine. These components include air cleaners, carburetors, exhaust systems and ignition systems. No special tools or training is required to perform these modifications, although it is recommended you are comfortable working on your own motorcycle.

Over the past several years we have installed and tested many manufacturers components. The list of parts used in building the ultimate 'bolt-on parts' engine is the end result of this testing. The best and least expensive of the individual components was selected and tested as a single package. The fact that virtually all the parts used for the project are from Harley-Davidson is a coincidence. There was no plan or idea to use mostly Screamin' Eagle parts for this project.

All the parts used are readily available through your Harley-Davidson Dealer except for the spark plug wires, which can be ordered directly through Magnecor. No special tuning was performed to achieve the results listed. All components were installed according to the manufacturer instructions supplied.

bulletBuilding the ultimate 'bolt-on parts' engine
Install the mufflers
Re-jet the carburetor
Install the air cleaner kit
Install the ignition module
Install the ignition coil
Install the spark plug wires
Change the spark plugs
Change the engine oil
Change the transmission oil
Road test the bike
Dyno Tune the bike

The results of the Dyno testing verified the improvements. The test results showed the engine was now producing 69 horsepower and 79 ft. lbs. of torque. This represents a 10 HP improvement over the stock power of 59 horsepower and 72 ft. lbs. of torque.

bullet 

The good results are due to a well matched set of parts being bolted-on to the engine. Seems that a little of that money the Dealers send back to Milwaukee is going into engine performance research.

The ability to create the same results with other manufacturers parts is a distinct possibility. Many optional parts should perform as well as the parts tested as long as you avoid drag pipes. Please be aware that your results may vary and other parts may not perform as well as the components tested listed.

Still not enough power for your needs? We decided to find out what happens when you take the Ultimate Stock Engine and make it a Stage 2 bike. There are more surprises ahead as we continue to step up the power in our "Ultimate Engine"  modifications series of articles.

bullet 

The Parts List for Bolt On Performance

Air Cleaner

Screamin' Eagle High-Flow Air Cleaner Kit for Carburetor
Harley-Davidson Part Number 29440-99
$129.95

Carburetor Parts

Stock Keihin CV modified using a
DynoJet Re-calibration Kit
Harley-Davidson Part Number 29604-00 for 2000 models
Harley-Davidson Part Number 29555-99 for 1999 models
$74.95

Exhaust System

Screamin' Eagle II Slip On Baloney Cut Muffler Kit
Harley-Davidson Part Number 80258-99
$199.95

Ignition System and Coil

Screamin' Eagle Performance Ignition System
Harley-Davidson Part Number 31710-99 for Dyna, Softail
Harley-Davidson Part Number 32721-99 for FL
$199.95

Plug Wires

Magnecor 8.5 mm Harley-Davidson Plug wire set
$24.95

Other Items

Harley-Davidson H-D Gold Spark Plugs
Harley-Davidson Oil Filter
Mobil 1 15-50w Synthetic Motor Oil (3 quarts)
Royal Purple 75w-90 Synthetic Transmission Oil (1 quart)

Other riders have been able to produce similar results

The Horsepower Gallery provides an extensive list of bikes , the power they produced and the major engine components.

 

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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
Shovelhead
Sportster
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
Camshafts
Selecting a cam
Install a TC 88/95 cam
Install a Big Twin cam
Install Sportster cams

Camshaft Specifications
Twin Cam
EVO
Shovel
XL


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

SHOP TALK
Shop Manual
Carburetor
Carburetor Troubleshooting
Exhaust
Ignition
Finding Manifold Leaks
Camshafts
Cylinder Heads
Pistons and Cylinders
Clutch
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
Miscellaneous
Performance Calculations
Estimate Horsepower
Estimate 1/4 Mile Time
Estimate Top Speed

Engine Displacement
Exhaust Length
Gear Ratios
MPH at RPM
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 -+-