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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

Rammer Performance Air Cleaners
TC Performance Heads 100+HP

Pro Tuning on a Shade Tree Budget


Stage 3 Modifications
Building a 128 horsepower 95CID Twin Cam engine

Performance and Technical information on Stage 3 modifications to a Harley-Davidson TC95  motorcycle engine.

How to get 128HP from your Twin Cam engine.

You have decided that your current engine isn't getting the job done. You have made Stage 2 changes to your bike and are still looking for more power. Maybe your bolt-on Harley parts aren't getting you down the road as quickly as you want? This this is the case, you are ready for a series Stage 3 engine.

Better flowing heads and increased compression ratios are the usual way to break the 100 horsepower mark with your Twin Cam engine. Motorcycle Performance Guide is about to blow the lid off this idea. We achieved 128 horsepower at the rear wheels by using a carefully matched set of components and a lot of tuning.

There are many companies out there that are competing for the dollars that Harley-Davidson 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 separate you from your money. Reading between the lines on many of the performance claims can be bewildering.

Does the Harley-Davidson world need another engine modification article? We 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. The Motorcycle Performance Guide staff and a select group of performance shops continue to obtain better results than the "experts" in the press and what you can get by bolting on Harley-Davidson engine parts.

How to build your own Stage Three engine


This Stage Three engine requires internal changes to the engine. Disassembly of the top end of the engine is required. Some special tools and training is required to perform these upgrades. Unless you are a very good mechanic and have access to a machine shop, it is recommended you find a competent shop to perform these modifications. For those of you that want to assemble the engine yourself, Motorcycle Performance Guide recommends you obtain the proper service manual for your bike.

Over the past several years we have installed and tested many manufacturers components. The list of parts used in building this engine is the end result of this testing. The best and least expensive of the components were selected and tested as a single package. The horsepower your bike produces may vary from the results produced here. If you use different parts or do not properly tune your engine, power may change significantly. Motorcycle Performance Guide assures you that the parts list and results are presented as accurately as possible.

The parts used in this engine are available through CycleRama (727-546-0889), after-market parts companies and your Harley-Davidson Dealer. The components were installed and tested in CycleRama's shop. Dyno tuning is required to achieve the results listed. All components were installed according to the manufacturer instructions supplied.

bulletBuilding your Stage 3 engine
Disconnect battery
Drain gasoline from tank
Remove gas tank
Disassemble the engine top end
Remove heads, cylinders and pistons
Remove cams, lifters and lifter blocks
Remove stock clutch
Swap stock heads for a set of CycleRama CNC ported heads
Send cylinders to machine shop to fit new pistons
Install cylinders with new pistons
Install upgraded cylinder heads
Install new cams
Install ignition module
Install lifter blocks with new lifters
Install adjustable pushrods
Install intake manifold and carburetor
Install new clutch
Install exhaust system
Change engine oil and filter
Change transmission oil
Add primary chaincase oil
Install new spark plugs
Set static ignition timing
Road test the bike
Dyno Tune the bike
Enjoy the ride

The results of the Dyno testing were excellent. The test results showed the engine producing 128 horsepower @ 6600 RPM and 118 ft. lbs. of torque @ 4300 RPM. The power curve on this engine is suitable for street riding. It produces over 100 ft.lbs. of torque from 3200 to 6600 RPMs. That is some serious power to the rear wheels.

This engine is producing 60 horsepower more than a stock Twin Cam engine. Not bad for the relatively low investment in time and money required to get these results.

bulletThe Dyno Run Sheet

The results are due to a well matched set of parts being installed in the engine. This is an engine combination that many Harley shops do not want you to know about. Who would believe a TC95 could make over 120 horsepower.

The heart of this upgrade is a set of CycleRama (727-546-0889) CNC Ported heads. The folks at CycleRama spent a lot of time optimizing the ports on the Twin Cam heads before committing to the current design. These heads will increase the power of your engine significantly.

The performance of the CycleRama designed cam is matched to the flow characteristics of the cylinder heads. This cam produced a wide power band.

The Thunderheader exhaust system was an important component in creating this high horsepower. 2-1 exhaust systems are known for their strong mid-range power and the Thunderheader did not disappoint us.

Other components used in this engine

bulletScreamin Eagle 44mm CV carburetor.
bulletScreamin Eagle Pistons.
bulletA performance clutch like the Barnett Scorpion is required to control this much power.

The ability to create similar results with other manufacturers parts is a distinct possibility. Motorcycle Performance Guide choose to work with parts that had proven ability to provide increased horsepower and torque. If you use the parts listed in the "Ultimate Street Engine" series of articles, there is little doubt in our minds that your can duplicate our results, provided the engine is in good mechanical shape and properly tuned. Optional parts that have similar specifications to the components used in our engine should provide very similar results. A matched set of engine components, careful assembly and dyno tuning are the keys to building a killer street engine. May your results be a successful as those we have documented.

The Parts List for Stage 3 Maximum Performance

Upgraded Heads

CycleRama CNC ported heads for Twin Cam


Screamin Eagle Pistons

Camshaft and valve train

CycleRama special grind for Twin Cam 

Exhaust System



Screamin Eagle 44mm CV

Ignition System

Crane HTC Ignition module
Magnecor Spark Plug Wires - cost $25.00


Barnett Scorpion

Other Items

Top End gasket set from Cometic Gasket
Primary chaincase gasket
Spark Plugs
Harley-Davidson Oil Filter
AMSOIL 20-50w Synthetic Motor Oil (3 quarts)
AMSOIL 20-50w motorcycle oil for  Transmission Oil (1 quart)
AMSOIL 20-50w motorcycle oil for Chaincase Lubricant (1 quart)

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


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 -+-