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


Engine Performance Dyno Runs
101 HP

Performance and Technical information on Stage 3 engines for Harley-Davidson motorcycles.

Stage Three Engine Development

When you already have a 95 HP engine, how do you proceed when making additional changes? If you are smart, you do it in small, incremental changes that you can verify along the way. The goal of 118 HP from an 80 Cubic Inch Harley-Davidson engine may be pushing things a bit, but there is an actual chance that it can be done.

The current 80 CID engine using stock Harley-Davidson cases, cylinders and heads is able to produce 95.3 Ft.Lbs. of torque at 4700 rpm's and 95.3 Horsepower at 5700 rpm. The power comes on unbelievably strong between 4000 and 6000 RPM. the first step in moving the horsepower up by 23 ponies was to check a few things on the current engine. A quick run on the dyno confirmed that peak HP readings had not changed, but with a couple of thousand miles on the engine, a close inspection of the top end of the engine seemed in order. Before the engine was disassembled, a compression test was performed on the engine. The results of this test told me that more power was available in the engine. 195 PSI in one cylinder, 180 in the other. A shot of oil the 180 cylinder brought it back up to 195. Was the problem wear or an assembly problem? Only the tear down would tell.

As the top end of the engine was taken apart, everything was inspected for damage and measured for wear. Special attention was paid to the pistons, rings and cylinder bores. With no signs of wear on any of the parts, the measuring took place. A small difference in the ring end gaps between the front and rear cylinders was found. This would explain the difference, but now how to eliminate it now became the issue. Re-installing the rings was out of the question and installing another set of rings could leave us with the same problem again. A quick review of the parts books reveled rings by Perfect Circle, a gapless ring. This should eliminate the problem, and the company provides a no leakdown guarantee.
While looking for ideas for improving performance, a brochure from One Cryo  on cryogenic tempering came to my attention. Normally any sane person would not believe claims of increased performance and durability by 'freezing' an engine, but you don't build high horsepower Harley-Davidson engines by picking up pieces at your local wrench's shop. This idea sounded so outrageous that it had to be a complete hoax or absolutely true. It was actually fairly easy to confirm that the cryogenics treatment is a form of tempering the metal. We all know that tempering is a good thing, so time to talk to Cryo One. A few discussions with the Cryo One people, it was decided to cryo treat the cylinders and pistons in an effort to reduce some of the friction and attempt to improve the thermal stability of the cylinder bores. The Cyro One people do not promise horsepower, but they do guarantee satisfaction with the cyro process. The number of people who attest to the effectiveness of the treatment is impressive.

Stage Three Engine Components

Year: 1994
Model: EVO
Bore: Stock (3.500")
Stroke: Stock (4.250")
Displacement: 1340cc (81.8 CID)
Cases: 1997 H-D
Assembly: Owner
Crankshaft and Flywheel: H-D
Heads: H-D
Porting: CycleRama, Pinellas Park, FL. (813) 546-0889
Intake Valves: Diameter (1.940")
Exhaust Valves: Diameter (1.615")
Valve Springs: Crane
Compression Ratio: 10.5:1
Pistons: JE 10.5:1 [Cryogenic Tempered]
Piston Rings: Perfect Circle
Cylinder Deck Height: 0.000 inches
Head Gasket Thickness: 0.030 inches
Cylinders: H-D [Cryogenic Tempered]
Cam: Crane Special Grind - 268 intake 272 exhaust w/ .600 lift
Valve Lifters: H-D stock [Cryogenic Tempered]
Pushrods: Crane Time-Savers
Carb: Mikuni HSR-42
Carb Jetting Information: 185 Main
Manifold: Modified Mikuni
Air Cleaner: None - Velocity Stack
Ignition: Crane HI-4
Ignition Timing: 33.5 Maximum Advance
Coil: Crane
Spark Plug Wires: Magnecor
Spark Plugs: H-D Gold
Pipes: Cycle Shack Slash Cuts - No Baffles
Dyno Tuning Facilities: CycleRama, Pinellas Park, FL. (813) 546-0889
Engine Oil: Royal Purple 20w-50
Engine Gasket Set: James Gaskets


wpe73.jpg (32719 bytes)

This Engine ended up producing 101 Horsepower at 6600 RPMs. During the AMI dyno shootout during bikeweek 98, the V-Twin Cafe bike was spining the Dyno at over 165 MPH in 5th gear roll ons with the red line set at 7000 RPMs. Despite our best efforts, the bike ended up Third in the 1201-1340cc Domestic Street class. We will try again next year.


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 -+-