The Prophet

These guys have been around... forever.

Megacycle Cams

Download the Catalog, as it is a great reference guide to the almost endless variety of Cam profiles available.

Note the cause/effect of Duration, LSA, lift, intake/exhaust openings and closings - and how they determine the cam "Type". Find a bike similar to yours and see the cause/effects from differing profiles.

Stock - Mild - Fast Road - Full Race, etc. 99% of us would be very disappointed with a "Full Race" cam in a street bike. Lot's of "peak" HP on a Dyno sheet, but a real pill to deal with for everyday riding.

Anyway, check it out, and note how higher and lower duration numbers effect the suggested end use. Check out the other cam specs, and how they effect the intended performance.


Now - do you want to purchase a Cam from a vendor without knowing the specifications? Would you take the advice from someone who's wallet has just been lightened by $1200.00?

Maybe it's better to become very familiar with the different profiles, and have a good, experienced Cam Grinder make one to YOUR specifications!

Ride Safe!

Bob

__________________

• A good traveler has no fixed plans, and is not intent on arriving. ~Lao Tzu
• Motorcyles are not my whole life, but they make my life whole. ` me

The Prophet

Some handy Cause / Effect notes on camshaft selection.

Go through the list, and tick off what you would like to see as an end result. This helps with the eventual selection process, and will result in the best cam shaft set for YOUR riding style and end-use.

VARYING LOBE SEPARATION ANGLE
Tighten ---Widen
Moves Torque to Lower RPM ----Raise Torque to Higher RPM
Increases Maximum Torque -----Reduces Maximum Torque
Narrow Powerband ----Broadens Power Band
Builds Higher Cylinder Pressure -----Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock ----Decrease Chance of Engine Knock
Increase Cranking Compression ----Decrease Cranking Compression
Increase Effective Compression ----Decrease Effective Compression
Idle Vacuum is Reduced ----Idle Vacuum is Increased
Idle Quality Suffers ----Idle Quality Improves
Open Valve-Overlap Increases ----Open Valve-Overlap Decreases
Closed Valve-Overlap Increases ----Closed Valve-Overlap Decreases
Natural EGR Effect Increases ----Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance ----Increases Piston-to-Valve Clearance


LOBE SEPARATION ANGLE
Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight


ADVANCING / RETARDING CAM TIMING
ADVANCING ----RETARDING
Begins Intake Event Sooner ---Delays Intake Event Closes Intake
Open Intake Valve Sooner ----Keeps Intake Valve Open Later
Builds More Low-End Torque ----Builds More High-End Power
Decrease Piston-Intake Valve Clearance ----Increase Piston-Intake Valve Clearance
Increase Piston-Exhaust Valve Clearance ----Decrease Piston-Exhaust Valve Clearance



As far as Duration goes, basically the lower the duration (low 200's) the lower the torque band peak, and the lower the "Peak" hp numbers. Roughly for every 10 degrees higher in Duration, you move the torque peak UP about 500 RPM.

Fully laden Harleys and other big Luxury Touring bikes would have the duratiion and torque band low to move around a heavy bike, passenger, and traveling luggage, etc.

A "zippy" sportbike/crotch rocket bike designed for a single rider / boy racer would have the duration larger, as in the 270 to 320 range, as 3 and 4 cylinder small bore/short stroke engines can more easily rev high. This style bike can take advantage of the light weight, single rider, and high rev motor, so the "Peak" is up in the 10,000 RPM range. This style motor would barely get a big, heavy bike off from a standing start.

At any rate food/fuel for thought. Trust this will help others properly understand, and choose, a nice cam set for their ride(s).

Ride Safe!

Bob

The Prophet

A good source for Camshafts. Web-Camshafts.

Note the questionairre (click on the icon to the left) wherein they ask the right questions, especially about YOUR intended end use for the bike.

Remember - if a camshaft supplier either doesn't ask these vitally important questions, and/or speaks only of "horsepower gains", or will not reveal the lift / duration / LSA, etc. - run, don't walk to the nearest exit. I've said it a zillion times - you cannot build a decent motor without knowing what the cam specs are. Impossible. Period.

These Web guys have been around for 60 years+, and have some great credentials.

Worth a consideration...

Web Cam Inc. - Performance and Racing Camshafts

Ride Safe!

Bob