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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 95 horsepower 1340 Evolution engine

Performance and Technical information on Stage 3 modifications to a Harley-Davidson 1340 Evolution motorcycle engine.

Build low cost, maximum performance street engine
How to get 95HP from your 1340 Evolution engine.

ssengine.jpg (19837 bytes)

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. You are ready for a series Stage 3 engine. These modifications are a little more complicated than the bolt-on Stage 3 engine.
Better flowing heads and increased compression ratios are the usual way to make 90+ horsepower. Motorcycle Performance Guide is about to blow the lid off this idea. We achieved 95.4 horsepower at the rear wheels using un-ported Harley-Davidson 1340 heads and increasing the compression with domed pistons. Contrary to what many performance shops try to tell you, we were able to break the 90 horsepower mark without larger valves, porting and polishing  the Evolution heads.

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 continues to obtain better results than the "experts" in the press and most performance shops.

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.

All the parts used in this engine are readily available through local shops, after-market parts companies and your Harley-Davidson Dealer. The components were installed and tested on a 1994 FXD Dyna Low Rider. 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 cam, lifters and lifter blocks
Remove old cam bearing
Remove stock clutch
Send heads to machine shop to install parts and do valve job
Send cylinders to machine shop to fit new pistons
Install cylinders with new pistons
Install upgraded cylinder heads
Install new cam bearing
Install new cam
Install ignition module
Install lifter blocks with new lifters
Install adjustable pushrods
Install intake manifold and carburetor
Install new clutch
Install exhaust system
Remove exhaust system baffles

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 95.4 horsepower @ 5600 RPM and 95.3 ft. lbs. of torque @ 4600 RPM. While the power curve on this engine was optimized for drag racing and dyno shootouts, it still manages to produce over 80 ft.lbs.. of torque from 3900 to 6000 RPMs. That is some serious power to the rear wheels.

This engine is producing 40 horsepower more than a stock bike. Not bad for the relatively low investment in time and money required to get these results.

Just how fast is fast enough is a matter of opinion. This 94 FXDL was taken to the drag strip in order to establish what 1/4 mile times could be done. The bike proved to be a very potent H-D drag race bike by turning times in the 11.80 range with 114 MPH speeds. The bike will accelerate to 90+ MPH in 1/8 of a mile.

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 stock Evolution heads could make over 90 horsepower.

Just because the heads were not ported and polished, don't think that you can achieve the high horsepower numbers without making some changes to the heads. The Manley performance valves and the 5 angle valve job provide big improvements in air flow through the ports. This is an important part of making good horsepower. Don't forget to have the spring clearance set for .600" lift cams. The SE-57 has a .575" bump on it. The JE 10.5:1 pistons are machined to accept a high lift cam.

The performance of the Screamin Eagle SE-57 camshaft was impressive, producing strong torque to match the horsepower potential. Past experience indicated that cams with 252 degrees of duration make excellent street cams. This Harley-Davidson camshaft did not disappoint.

The SuperTrapp 2-1 exhaust system with the internal baffles removed was an important component in creating this high horsepower. Installation of the baffles and use of 18 disks results in a 5-7 horsepower drop, but the torque remains the same. The horsepower curve peaks drops to 5700 RPM and the torque peak drops to 3900 RPM. This change in power curve makes the engine very potent on the street.

If don't have the money to purchase all the parts listed for this engine, we recommend you make the following changes

bulletUse your re-jetted CV carburetor in place of the Mikuni HSR-42. The CV is capable of supporting a 90 HP engine. Just keep your Screamin Eagle air filter clean and make sure the carburetor is well tune.
bulletThe Cycle Shack Slash-cut exhaust system or Slip-on mufflers on stock header pipes are a low cost alternative to the SuperTrapp 2-1. While the maximum power of the 2-2 exhaust system is not going to match the 2-1 system, expect only a small horsepower drop.
bulletThe Barnett Extra Plate clutch is a good alternative to the Rivera Pro Clutch. With the extra power available from the engine, the stock clutch will not last very long if your riding style is aggressive. While the Barnett upgrade will not last like the Rivera, the cost difference is significant.

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
New parts cost estimated at $2,924 plus tax.
New parts cost assumes the purchase of all parts listed.
Using optional parts list, cost estimated at $1,680.

Machine Work cost estimated at $400 plus tax.
Maintenance parts cost estimated at $200 plus tax.
Dyno Tuning costs estimated at $200 plus tax.

Upgraded Heads

Stock 1340 EVO heads
Manley Stainless Steel Performance Valves
- cost $160.00
Crane 155# Valve springs - cost $115.00
5 angle valve job
Set spring height for .600" cam lift


JE 10.5:1 compression pistons - Cost $250.00
Perfect Seal Piston Ring set - Cost $50.00

Camshaft and valve train

Screamin Eagle SE-57 camshaft - Cost $200.00
Torrington B-138 cam bearing - cost $6.00
Screamin Eagle Chrome-Moly Adjustable Pushrods - Cost $90.00
Use 97 or later Harley-Davidson lifters - cost $25.00 each 

Exhaust System

SuperTrapp 2-1 with baffle removed - cost $450.00
option: Cycle Shack 2-2 Slash-cut exhaust - cost $175.00


Mikuni HSR-42 - cost $550.00
Mikuni Intake Manifold - included above
option: CV with DynoJet kit and SE air cleaner

Ignition System

Crane HI-4 Ignition - cost $231.00
( We do not recommend using the Dyna 2000 ignition module. )
Crane Single Fire Coil - cost $127.00
Magnecor Spark Plug Wires - cost $25.00


Rivera Heavy Duty racing clutch - cost $570.00
option: Barnett Extra Disk Clutch - cost $150.00

Other Items

Top End gasket set from James Gasket
Primary chaincase gasket
Autolite 4265 Spark Plugs
Harley-Davidson Oil Filter
Mobil 1 15-50w Synthetic Motor Oil (3 quarts)
Royal Purple 75w-90 Synthetic Transmission Oil (1 quart)
Harley-Davidson 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 -+-