MTC Knowledge Base
Everything We Know, In One Place
Guides written by the people who do the work — plus the interactive tools riders use every day. New articles land here as they publish.
VIN DecoderDecode any motorcycle VIN — year, make, model, plant.Tire Size DecoderWhat every number on your sidewall actually means.Tire Age DecoderRead the DOT date code — know how old your rubber really is.Bias-Ply vs Radial Motorcycle Tires, ExplainedBias and radial motorcycle tires are built differently, and it changes how they ride. The construction difference explained simply, plus how to tell which you have.Read →Carb Rebuild vs Clean & Tune: Which Does Your Bike Need?Hard starts, rough idle, bogging throttle — is it a cleaning or a full rebuild? How to tell the difference, and what each actually involves.Read →Crash Repair: What Happens After You Go DownFrom tip-over to total rebuild: how damage gets assessed, how the insurance estimate works, what to document, and what to expect at each step.Read →Fork Oil & Suspension Service: The Maintenance Riders ForgetFork oil wears out just like engine oil — but nobody changes it. What suspension service includes, the ride-feel symptoms of worn fork oil, and when it's due.Read →Harley-Davidson Fault CodesHarley-Davidson fault codes explained: look up P, B, C & U DTCs and how to read or clear them without a scan tool. From MTC in Orange, CA.Read →How Long Do Motorcycle Tires Last?Motorcycle tires wear out two ways — by mileage and by age. See the typical ranges by tire type, what shortens tire life, and how to tell when it's time.Read →How to Check Your Motorcycle Tire's Age (DOT Date Code)Your motorcycle tire's age is stamped on the sidewall. Learn to find the DOT date code and read the last 4 digits — the week and year it was built.Read →How to Read Your Motorcycle Tire SizeFind the right motorcycle tire size for your bike. Harley-Davidson, Honda, Yamaha, Kawasaki, Suzuki, sport bikes and cruisers. Free tire size reference guide from MTC in Orange, CA.Read →Motorcycle Brake Service: Pads, Rotors, and Fluid ExplainedWhat actually wears out in a motorcycle braking system, the warning signs for each part, and what brake service includes — explained straight.Read →Motorcycle Oil Change: Why Harley Takes Three (and Most Bikes One)Big Twin Harleys hold oil in three separate compartments — most bikes use one. What that means for service, what fresh oil actually does, and when to change it.Read →Motorcycle Tire Pressure Guide by Bike TypeThe right motorcycle tire pressure is on your bike's placard or in the manual — not a generic chart. Why cold PSI matters and how to check it right.Read →What Is a Cam Job?What a camshaft does, why Harley riders upgrade, what a cam job includes, and the honest trade-offs — explained in plain language by the shop that does them.Read →What Is a Fork Seal — and How Do You Know Yours Is Leaking?What fork seals do, the telltale signs of a leak, why it's a braking-safety issue — not cosmetic — and what replacement involves.Read →What Is a Stage 1 / Stage 2 Upgrade?What "Stage 1" and "Stage 2" actually mean on a Harley, why the definitions vary, and the logic of the upgrade path — explained without the hype.Read →What Is a Valve Adjustment?What valve clearance is, why it drifts out of spec, the warning signs, and why skipping adjustments risks real engine damage — in plain language.Read →When Should You Replace Your Motorcycle Tires?Complete guide to knowing when to replace your motorcycle tires. How to read the DOT date code, why old tires fail even with good tread, tread depth limits, and what to look for on inspection. From MTC in Orange, CA.Read →Why Tire Balancing Matters (and What Happens If You Skip It)What balancing actually corrects, the symptoms of an unbalanced motorcycle tire, and why it's standard with every install — for $9.95 a tire.Read →