Harley Twin Cam
Harley Twin Cam
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 Harley Davidson Evolution Twin Cam 88 Chrome Header Mount Hardware  US $3.33
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 2004 Harley Davidson FL Touring FLHT Twin Cam Black Oil Hose Cover Electra Glide US $10.00
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 HARLEY DAVIDSON STOCK CAM EARLY BIG TWIN US $29.95
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 Harley Davidson Cam Bearing Tool RENTAL 1999 to 2006 Twin Cam execpt 2006 Dyna US $38.00
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 Harley Davidson Andrews 59HG G Grind Cams for Twin Cam P N DS199251 US $339.95
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 Harley Davidson Andrews 64HG G Grind Cams for Twin Cam P N DS199252 US $339.95
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 EP12856 Harley Twin Cam motor engine rocker box covers US $220.00
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS FORCES US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS SKET US $99.99
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 Chrome Bolt Topper for Harley Dyna Glide FXD Twin Cam 88 Super Sport Low Rider US $29.95
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 Electraeon Engine Badges for Harley Davidson Twin Cam Motors US $44.00
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS B SAIN US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS CRM SK US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS CROSS US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS CRSS US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS DFG US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS EZ2 US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS FORCE2 US $99.99
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 HARLEY DAVIDSON CUSTOM DERBY COVER TWIN CAM BIG TWIN SPORTSTER MODELS GRENAD US $99.99
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 Harley Chrome Lot of Parts Touring Twin Cam Electraglide US $34.00
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 Harley H D V Twin Cam Engine Rebuild Gear Piston DVD US $49.95
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 9203 Twin Cam nose cone cam timer cover 4 Harley motor US $55.25
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 EP12721 black Harley Twin Cam rocker box covers motor US $255.00
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 Harley Davidson Camshaft Tool Twin Cam Chain Tensioner Unloader TC88 Made in USA US $29.99
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 HARLEY DAVIDSON STOCK CAM COVER TWIN CAM US $25.00
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 HARLEY DAVIDSON 103ci Chrome TIMER COVER w RED all Twin Cam 99 US $89.98
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 HARLEY DAVIDSON 103ci Chrome TIMER COVER w TEAL all Twin Cam 99 US $89.98
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 PYROSTARS SPARK PLUGS FOR TWIN CAM HARLEY DAVIDSONS US $25.00
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 HARLEY DAVIDSON TWIN CAM PERFORMANCE CYLINDER HEADS US $795.00
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 FITS HARLEY TWIN CAM HI PERFORMANCE ACCEL SPARK PLUGS US $18.64
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 HARLEY DAVIDSON TWIN CAM SCREAMING EAGLE AIR CLEANER INSERT NEW FREE SHIPPING US $9.99
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 Harley Twin Cam 88 Inner Cam Bearing Puller Installer US $114.99
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 HOT TOPPERS HTD88 COMPLETE KIT HARLEY DAVIDSON TWIN CAM FL ROADKING TOURING US $200.00
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 EP9946 Harley Twin Cam FL Dyna FXST brake caliper US $100.80
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 Harley Davidson Chrome Head Bolt BridgeTwin Cam US $34.95
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 EP6478 oil pressure gauge mount Harley Twin Cam motor US $85.00
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 CHROME HORN COVER for 92 12 Harley Davidson Softail Dyna Glide Big Twin Electra US $24.95
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 harley dyna evo twin cam kuryakyn 8139 cylinder base timing holecover w linkag US $49.99
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 LOT OF 10 O RING DRAIN PLUG GASKET TWIN CAM HARLEY DAVIDSON 1999 2011 11105 US $6.95
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 Chrome HORN COVER for Harley Softail Dyna Glide Big Twin Electra Road King 96 up US $33.95
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 JIMS CAM CHAIN TENSIONER TOOL FOR TWIN CAM 88 HARLEY DAVIDSON 1999 2006 1283 US $48.95
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 HARLEY TWIN CAM BIG TWIN POINTS COVER CUSTOM ENGRAVED US $52.00
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 HARLEY EVO TWIN CAM DYNA SOFTAIL TOURING V WING TRANSMISSION END COVER KIT US $19.00
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 Harley V Wing Transmission End Cover87 up 1340 Twin Cam 88 Mdls US $17.95
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 HARLEY DAVIDSON SPACER CAM DRIVE 355 1999 B TWIN PART 25595 99 US $19.99
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 100th Anniversary Harley Davidson 2003 Engine Medallion Twin Cam Black Chrome US $79.00
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 Jack Daniels Harley Old 7 5 hole timer cover Chrome fits Twin Cam US $24.99
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 EP11577 Harley Twin Cam inspection derby cover Dyna FL US $36.00
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 Oil Pressure Gauge Kit for Harley Davidson Twin Cam models 99 later US $78.00
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 Harley Parts New Twin Cam Lifter Block Bolts POLISHED US $14.99
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 HARLEY DAVIDSON CHROME TWIN CAM 88 CUBIC INCH 5 HOLE DERBY COVER US $44.99
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 HARLEY TWIN CAM FINNED HEADBOLT COVER 43840 01 GRAY US $49.99
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 harley evo twin cam billit aluminum upper motor mount 2 piece new US $59.99
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 EP12022 Harley Twin Cam chrome inspection derby cover US $33.60
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 CHROME SPARK PLUG COVERS 11 16 HARLEY TWIN CAM XL US $13.99
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 Motion Pro 08 0153 Cam Cover Puller For Harley 74 80 Big Twin XL Models US $25.43
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 EP8536 Harley Twin Cam tranny transmission side cover US $79.80
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 HARLEY DAVIDSON TWIN CAM LIFTERS PLUS US $25.00
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 HARLEY 28 Twin Cam Olive 118 CE US $5.99
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 Harley Davidson Skull Derby Cover Multi Fit New in Pkg HOG 25441 04A US $29.99
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 harley evo twin cam sporstster headbolt covers king cone style handmade alum US $129.99
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 EP11580 Harley Twin Cam inspection derby cover 60769 06 US $42.50
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 Harley Davidson Inner Cam Bearing Puller Tool Twin Cam TC88 US $59.99
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 Harley Davidson Inner Cam Bearing Installer Tool Twin Cam TC88 US $49.99
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 Custom Blue Glitter Dice Air Cleaner Bolt for Harley Twin Cam Filter Cover US $9.95
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 Custom Red Glitter Dice Air Cleaner Bolt for Harley Twin Cam Filter Cover US $9.95
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 Custom Clear Glitter Dice Air Cleaner Bolt for Harley Twin Cam Filter Cover US $9.95
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 Jims 788 Exhaust Gasket Seal Installer Tool For Harley 84 11 Twin Cam XL US $39.99
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 EP6843 Harley brake pads 44082 00C Twin Cam Dyna FL Softail Road King Sportster US $58.10
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 Custom Blood Red Short Spike Air Cleaner Bolt for Harley Twin Cam Filter Cover US $29.95
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 Jerzee Customs Black Oil Pressure Gauge Kit for Harley Davidson Twin Cam US $119.95
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 Harley Davidson Black Oil Pressure Gauge Kit Twin Cam US $119.95
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 Harley Davidson Inner Cam Bearing Installer Dyna Twin Cam TC96 US $49.99
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 IGNITION COVER fits HARLEY TWIN CAM 1999 PRESENT US $12.99
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 Harley Twin Cam Cylinder Heads Breathers Aluminum US $29.00
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 Custom Brass Rocket Air Cleaner Bolt for Harley Twin Cam Filter Cover 3 Wing US $14.95
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 Harley Davidson Wheel Bearing Installer Puller for Twin Cam Sportster V Rod US $169.99
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 Harley Touring Evo Twin Cam 1996 2007 Throttle Idle Cables Black 43 US $32.00
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 1958 1999 CAM TOOL KIT HARLEY INDIAN USA MC US $121.95
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 1991 2012 Harley Twin Cam Dyna Glide chrome toppers bolt caps US $24.50
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Planning for a Cam Change
Today's dissertation is about planning for a cam change. You have changed exhaust, upgraded the air cleaner/carb selection, and now its time to move to the next step. Using the highest lift, longest duration cams, are not always your best choice. Even though in some combinations they can work very, very well, using them with components that are not designed to compliment the cam can often disappoint. Here are some important points.
• We have to decide what RPM we want to develop the best power at.
• When we establish that RPM, there is no free lunch. In order to perform better at high RPM, we sacrifice low-end performance. Also, the inverse is true. Good performance at low RPM hurts top end performance. There is no way around this.
• If in doubt, you are always better choosing the conservative choice.
After making the decision about where we want to build power, we can make some educated choices. Mikuni North America gave me a nice guide that I have used in cam choices for a long time.
Cam Basics:
Correct cam selection is the single most difficult choice facing the performance enthusiast. And, unfortunately, we get it wrong about as often as we get it right. An incorrect cam choice can result in decreased real-world performance if the selected cam's operating range is not matched to riding style.
The operating range of any Harley engine is determined by a number of factors and the cam design is one of the most influential. If the cam design is not matched to the other components, and it's not matched to the desired engine power band (rpm range), then the engine's performance will be disappointing. No amount of carburetor tuning can compensate for having the wrong cam.
To get the "right" cam design, you need to do two things: First, decide upon the rpm range you want to improve. Secondly, use the list provided below and cam catalogues to select a cam design that begins to work at the lower rpm of the power range you have chosen. You'll probably be surprised to learn how few of the available cam designs fit your expectations.
Cam timing: What matters?
The most important cam-timing event is the intake valve-closing angle. The intake closing point determines the minimum rpm at which the engine begins to do its best work. The later the intake valves close, the higher the rpm must be before the engine gets "on the cam."
Long duration, late closing cam designs are necessary to drag the last bit of power out of an engine. Unfortunately, these same cams can perform poorly under more normal riding conditions. In the quest for maximum power output, many-too-many Harley owners choose a late closing, high-rpm cam for their engine. The problem with such choices is that the engine seldom spends time in the rpm range favored by such cams.
The majority of virtually any Harley motor's life is spent in the mid-portion of its rpm limits, between 2000 and 4000 rpm. At open-road cruising speeds, that range is more like 2500 to 3500 rpm. With current Big Twin gearing, top gear at 2500 rpm returns a road speed of 55 mph and 3500 delivers 84 mph. Riders sometimes "putt" around at 2000 or less. Even when accelerating to cruising speed, few of us use more than 4000 – 4500 rpm as a shift point. Very seldom, in day-to-day use, do our engines get near 5000 rpm, let alone 6000.
Even the mildest of Harley-Davidson's aftermarket cams (Evo or Twin Cam) do their best work above 3000 rpm. At 2000, the majority of these cams seldom perform significantly better than stock cam(s).
The rpm at which a Big Twin gets "happy" can be predicted by the closing point (angle) of the intake valves. The angle is expressed as the number of degrees After Bottom Dead Center (ABDC) that the valves reach .053″ from being fully seated.
The calculations below predict the rpm at which the engine gets "on the cam" based on the closing angle of the intake valves.
- 30 degrees = 2400 rpm
- 35 degrees = 3000 rpm
- 40 degrees = 3600 rpm
- 45 degrees = 4000 rpm
- 50+ degrees = 4500 rpm
These relationships are approximate but should hold true to within 200 rpm or so. They also assume that all other tuning factors, exhaust, ignition, etc., are operating correctly.
If you have one of the late closing cam designs installed, say one that closes the intake valves later than 40 degrees, then you cannot expect excellent performance at 2000 rpm. No carburetor adjustment, ignition adjustment or exhaust system can change this.
About the Author
You can find more information and all the motorcycle parts and accessories you need at J&P Cycles. J&P Cycles carries Harley parts, Vintage Harley parts, metric cruiser parts and Gold Wing parts.