Recent content by Eric Gorr

  1. Eric Gorr

    Suspension Tuning, By Eric Gorr. Part 3

    The Shock Dyno A shock dyno is a computer controlled electro-hydraulic machine that simulates and measures the damping characteristics of dampers (rear shock or front fork). A shock dyno is comprised of an electric motor, a hydraulic ram, a mounting guide, and a load cell (pressure transducer)...
  2. Eric Gorr

    Suspension Tuning, By Eric Gorr. Part 2

    Internal and External Adjustments Suspension dampers can be adjusted two ways, internally and externally. External adjustments are limited to the riding circumstances and the adjustment range on the compression and rebound clickers. Internal adjustments are virtually unlimited because it...
  3. Eric Gorr

    Suspension Tuning, By Eric Gorr

    Suspension Revalving How Damping Works Suspension fluid (oil) flows through the ports of the piston and up against the shims. The shims pose a resistance to the oil flow, which provides a damping effect. The damping effect is directly related to the diameter and the thickness of the shim. The...
  4. Eric Gorr

    Porting: Tools Of The Trade, By Eric Gorr

    Tools of the Trade There are two main types of tools used in porting, measuring and grinding. Here is an overview of how these tools are used. Measuring The basic measuring tools include a dial caliper, an inside divider, and an assortment of angle gauges. The caliper is used to measure the...
  5. Eric Gorr

    Cylinder Porting: Basic Principles By Eric Gorr

    Terminology These are some common words and terms associated with porting. Ports Passageways cast and machined into the cylinder. Ducts The tube shape that comprises the ports. Windows The part of the port that interfaces the cylinder bore. Exhaust Port The large port where the burnt...
  6. Eric Gorr

    Cylinder Porting: Basic Principles By Eric Gorr

    The process of cylinder porting is a funny paradox. The people in the market to buy it are looking for information and the people in the market of selling it are hiding information on porting. So much myth and misinformation is associated with this complex machining and metal finishing process...
  7. Eric Gorr

    Carb Tuning - Page 6, By Eric Gorr

    < Previous Page ... 5 Fuel and Oil Mixture Ratios When we talk about the "fuel" in the air-fuel mixture for a two-stroke engine, we are really talking about a mixture of fuel and oil. If you richen the pre-mix ratio (20:1 as opposed to 30:1) there is more oil and less fuel in the same volume...
  8. Eric Gorr

    Carb Tuning - Page 5, By Eric Gorr

    < Previous Page ... 4 Jetting for Riding Techniques Certain types of riders require jetting to compliment their technique. For example beginner minibike riders will need slightly richer jetting on the pilot/slow jet and the needle clip position to mellow the powerband and make it easier to...
  9. Eric Gorr

    Carb Tuning - Page 4, By Eric Gorr

    < Previous Page ... 3 Jetting Shouldn't Be Scary! Jetting is the process of making adjustments to the air and fuel jet sizes in order to fine tune the carburation to suit the load demands on the engine and make the power delivery consistent and optimum. Too much anxiety is placed on jetting...
  10. Eric Gorr

    Carb Tuning - Page 3, By Eric Gorr

    < Previous Page 2 Mechanical Problems The process of jettingÑchanging air or fuel jets in order to fine-tune engines' performanceÑis very simple. Jetting becomes complicated because mechanical problems sometimes mimic improper jetting. This causes you to waste time and money trying to correct...
  11. Eric Gorr

    Carb Tuning - Page 2, By Eric Gorr

    < Previous Page Fuel Jets, Air Jets, and Throttle Positions Three circuits control the air: the air-screw, the throttle slide, and the air jet. Four circuits control the fuel: the pilot/slow jet, the spray-bar/needle jet, the jet needle, and the main jet. The different air and fuel circuits...
  12. Eric Gorr

    Carb Tuning - Page 1, By Eric Gorr

    The Differences in Two-Stroke and Four-Stroke Carbs The difference between a two-stroke and four-stroke engine is intake velocity. Two-stroke engines have lower velocity so the needle jet has a half-moon shaped hood protruding into the venturi to produce a low pressure area that aids in drawing...
  13. Eric Gorr

    Carburetor Tuning - Intro, By Eric Gorr

    Carburetor tuning has the greatest effect on engine performance. When a motorcycle manufacturer builds a bike, they usually install jets in the carb that are too rich. The manufacturers sell the same model worldwide, so they couldn't afford to install different jets in the carb to suit all the...
  14. Eric Gorr

    Article: VALVE TRAINS Part 2

    You can view the page at
  15. Eric Gorr

    Uh Oh, Piston hit head. Confused.

    The spark plug is off-set bon an angle on the 1992-96