Four-Stroke Dirt Bike, Dual Sport & ATV Tech Info on 4Strokes.com

Non-Model Specific: Technical Info | Tips | Links

Airbox Mod - I noticed a crisper throttle response and the engine seemed to rev faster. -ThumperTDC

Buying Used? Educate Yourself - Pete suggests educating yourself before going to look at used dirt bikes to avoid buying trash. -Pete Marshall

Calculate Top Speed (Forums) - Calculate theoretical top speed for any dirt bike or ATV. -jg

California Motorcycle Requirements (2.2M PDF) - California Highway Patrol official document listing complete motorcycle codes.

Carburetor Jetting - Carburetor jetting can be easily understood if we know the basic principles of a carburetor and four-stroke engine operation. -Magazine Reprint

Carburetor Jetting Crossover Chart - Carburetor jetting crossover reference for Keihin carb jets, Dynojet carb jets, and Mikuni carb jets. -Troy

Carburetor Jetting Tricks, Four-Stroke - A four-stroke engine is basically an air pump and the carburetor meters how much air and fuel go in the engine. -Chris

Carburetor Overview, Keihin - Carburetors on dirtbikes should perform well with standard settings under average load, climatic and barometric conditions. -4Strokes.com

CDI Testing - Procedure to test a motorcycle CDI unit when you suspect it might be faulty. -qadsan

Chain Guard Flap - Keep the chain lube from flinging on your wifes back while riding. -HorseRider650

Fault Finding Flow Chart for Motorcycle Charging Systems

Charging Systems Fault Finding Chart (88K PDF) - The most common fault in electrical systems are bad connections. -Electrex

Crankcase Breather Mod - This dirt bike crankcase breather mod can be done to allow the crankcase to breath better. -superhondaz50

Dirt Bike Basic Overhaul - How to perform a basic overhaul on your dirt bike that will keep it running good all year long. -NOS

Dirt Bike Lift Plate for Floor Jack - Convert a floor jack to to a dirt bike lift. -Edward McCafferty

Dirt Bike Mounted Tire Irons - Drill holes in tire irons and bolt to the frame of your dirt bike. -MarkN

Dual Sport Conversion Info (Forums) - Dirtbikes registered for street must have equipment listed by your state motor vehicle code.

Dual Sport Use Helmet Mods - These folks modified standard helmets slightly for better dual sport use. -Various

Dual Sport Lighting, Build Your Own - Stu sourced parts and built his own dual sport lighting at a fraction of the cost. -Stu

Dual Sport Lighting Conversion and Wiring Diagram - Mark converted his dirt bike to dual sport and this is how he did it. -Mark

Dual Sport Lighting Schematic, Baja Designs Kit (70K gif) and Wiring Diagram (60K gif). -Jeff Moon

DIY Keyed Ignition Switch (Forums) - Install a keyed ignition switch on a dual sport dirtbike that did not already have one. -b_king

Dual Sport Requirements Per State 6/07 - Minimum requirements for dualsport motorcycles in the US. 6/06 Version, 7/98 Version. -MSF

Exhaust Header Wrap - Keep exhaust temperatures confined by using exhaust wrap. -Ygrumyz

Emergency Cable Fix - A way to fix a cable if the end pulls off and you are miles away from civilization. -Randy Ressell

Exhaust dB Reducer - This may also work for other aftermarket exhaust systems to reduce exhaust noise levels. -Ken

Fix a Cracked or Broken Case - The price of a new case can be expensive and in most cases it can be fixed for a fraction of the cost. -Brian10

Fork Oil Adjustment - Drain the forks and then accurately set the initial oil level. It is a lot easier than you think! -Michael Hetrick

Frame Guards, Make Your Own - Various versions of custom inexpensive frame guards. -Various

Four-Stroke Starting Procedures - To help you learn the easiest way to start a four-stroke. -4Strokes.com and others

Headlight Protectors - How to build an inexpensive headlight protector or headlight guard for your dirtbike or ATV. -Various

Garage Door Opener for a Dual Sport - Integrate your spare garage door opener on your dual sport. -Jlutty650L

Gear Ratio Chart (13K PDF) - Countershaft and rear sprocket gear ratio chart. -4Strokes.com

Gearing Calculator (42K Excel) - Calculate speed for primary and final gearing, wheel size and RPM. -Chris Helberg

Helmet Sizing - For AFX, AGV, Grex, Icon, M2R, MDS, Moose, Nolan, Suomy, Thor, and Z1R helmets.

Horsepower Calculator - Calculate the approximate HP of a dirt bike if you know the bike and rider weight and ¼-mile time. -4Strokes.com

Conventional Fork Leg Protectors - Make your own lower fork leg protectors from inexpensive PVC pipe. -NOS

How to Setup Disc Type Exhaust Systems - Meant for the XR600R and XR650L with White Brothers E-series exhaust but may help with setup of other disc type exhausts. -White Bros

Exhaust Sound Measurement (40K PDF) - Standard procedure, environment and instrumentation for determining exhaust sound levels. -SAE Committee

Motorcycle or ATV Storage Procedures - Motorcycle or ATV items that should be addressed before putting it up for winter or long term storage. -Robb Nelson

Oil Drain Funnel - Why pay $20 for a special 'man' funnel when you can make your own for less than $2.00! -KingTutt

Painting Vinyl Seats - Are you tired of that old faded seat? Do you have a late 80s KLR with a color scheme designed by Kawasaki's watercraft department? -Dale Wagler

Plastic Restoration via Painting - It is no secret that dirt bike plastic fades and tanks yellow and lose decals as they age. After good advice, this is what Ed found to work well. -Edward Pinzel

Rear Fender Bag - An inexpensive rear fender bag for dirt bikes that do not have a rear luggage rack. -Jlutty650L

Rear Wheel Alignment Tool - Build a rear wheel alignment tool yourself out of some PVC pipe for just a couple bucks. -Dave Morgan

Registration Decal Saver - No more destroyed California registration stickers when you remove your fork legs for service! To be done at your own risk. -4Strokes.com

Rim Lock / Bead Lock Install - If you switched from dualsport tires to knobbies, chances are you will need to install a rim lock. -4Strokes.com

Seat Cover and Graphics Installation - How to remove and install a seat cover and graphics. -4Strokes.com

Side Panel Skids - Teflon rods cut in half lengthwise then attached to the side panels with counter-sunk bolts. -motomonte

Spark Plug Reading - How to check carburetor jetting by reading the spark plug. Includes NGK part numbering PDF. -4Strokes.com

Spring Preload, Race Sag and Suspension Adjustments

Spring Preload, Race Sag & Suspension Adjustments - Setting the proper race sag is important for competition use. -4Strokes.com

Tire Removal and Installation Procedures (5) and Tips -4Strokes.com and others

Tire Sizing, Dirt Bike - Dirt bike tires have numbers indicating tire width, aspect ration (height) and rim diameter. -4Strokes.com

Top Speed Calculator V2.1 (151K ZIP) - Calculates top speed using engine, gearing, exhaust, cam lobe, and HP. -KAMware

Understanding a Basic Dirt Bike Suspension - There are a few basic forces at work in suspensions that must be understood before making successful changes. -NOS

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Non-Model Specific Subcategories: Technical Info | Tips | Links