V-Twin Diagnostics

Diagnose Your Harley Yourself — Free Tools, No Account Needed

Skip the $500–$1,000 dealer diagnostic. Start free — DTC codes, torque specs and service intervals, no account, no signup. When something is actually wrong, one Diagnostic Pass is $9.99 and a simple symptom-based Q&A points you to the probable failed part. No subscription. Built for fuel-injected Harley-Davidson motorcycles, 2007 to current. No hardware required.

Download on the App Store Get it on Google Play
Fuel-Injected Twin Cam · Milwaukee-Eight Evolution · Revolution Max 2007–Current

Before a single part is replaced, you're already $300–$450 in.

The standard dealer ecosystem — tow, scan fee, first hour of shop labor — adds up before anyone has actually fixed anything.

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Tow to the Dealer

Flatbed motorcycle tow runs $100–$300 before anyone even looks at your bike.

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Wait Days or Weeks

Service departments book out fast, especially in riding season. Expect days to weeks on the lift waitlist.

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Pay to Plug a Scanner In

Once they get to it, the diagnostic fee runs $50–$100+ just to identify the problem.

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Then the Hourly Clock

Shop labor runs $100–$200 per hour plus parts — and that's before anything actually gets repaired.

Save Your Hard-Earned Cash
Diagnose It Yourself — Instantly
Same systematic process a Harley mechanic uses. No tow. No wait. No $190/hour.

What You Get For Free

The reference tools every Harley owner should have — no account, no signup. Always in your pocket.

FREE WITH ACCOUNT
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Oil Change Tracker

Odometer-based reminders for all three sumps — engine oil (with filter), primary, and transmission — matched to your exact bike, so a service never sneaks up on you. Create a free account to use it.

Get started on the web → FREE · NO ACCOUNT
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DTC Code Lookup

71 diagnostic trouble codes in plain English, each with the probable causes behind the code — no scan tool needed.

Use it free on the web → FREE · NO ACCOUNT
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Torque Specifications

119 torque specs organized by system — Twin Cam and Sportster Evo engines plus per-platform chassis fasteners.

Use it free on the web → FREE · NO ACCOUNT
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Service Intervals

Factory-recommended maintenance schedules linked to your motorcycle's mileage.

Use it free on the web →
ANNUAL
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Complete Motorcycle Specifications

Electrical and mechanical specifications for your exact year, model, and engine — battery, charging, ignition and more. Included with the Annual License.

WITH ANY PURCHASE
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Your Garage

Any purchase unlocks your garage with full specs, service records and notes — up to 5 motorcycle profiles with Diagnostic Passes, 20 with the Annual License.

🎁 BONUS OFFER!

Limited Time — Register Now & Get the Oil Change Tracker Free

Odometer-based reminders matched to your exact Harley — your model, your mileage, what you've already done — so an engine oil, primary, or transmission service never slips by again. Track all three sumps independently. Download the app, create your account, and it's yours: locked in free on your account.

Diagnostic Passes & the Annual License

No subscription required. One diagnostic is $9.99 and never expires — or go unlimited for a year for less than half of one dealer diagnostic fee.

DIAGNOSTIC PASS
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Guided Diagnostic Paths

12 symptom-based Q&A decision trees: answer plain questions about what your bike is doing and the app correlates those behaviors to the probable component failure — the way a seasoned tech reasons it out.

PASS + ANNUAL
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Illustrated Component Cards

See the actual part behind each probable cause — what it is, where it lives, and what it does. Included in the report for the diagnosis you ran; the full browsable library comes with the Annual License.

PASS + ANNUAL
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Operational Circuit Diagrams

Diagrams for all 12 EFI and mechanical systems — ignition, fuel, starter, sensors, security, ECM power, brakes, wheels, suspension, steering, drivetrain, and leaks & noises. Included in the report for the diagnosis you ran; the full browsable library comes with the Annual License.

ANNUAL ONLY
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Mechanic’s Checklists

Five checklists with pass/fail tracking and PDF export — Pre-Ride, General Health, Battery & Charging, Comprehensive EFI Health, and Pre-Purchase Inspection.

ANY PURCHASE
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Multi-Bike Garage

Any purchase unlocks your garage — up to 5 motorcycle profiles with Diagnostic Passes, 20 with the Annual License. Full specs and service history on each.

DIAGNOSTIC PASS
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PDF Diagnostic Reports

Generate branded, sharable diagnostic reports with circuit diagrams, findings, and probable causes.

DIAGNOSTIC PASS
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Diagnostic History

Save and review every completed diagnostic over time on each bike in your garage.

SHARE
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Be a Hero

Know a Harley owner whose bike is down? Send them V-Twin Diagnostics and save them the tow, the wait, and the dealer scan fee.

Share Now →

Supported Models

Built for fuel-injected Harley-Davidson motorcycles from the 2007 model year to current, by engine platform — Evolution Sportster, Twin Cam, Milwaukee-Eight and Revolution Max. One line per family:

Sportster · 2007–2022 Evolution 883 & 1200 — plus 2021–current Revolution Max (Sportster S, Nightster) Dyna · 2007–2017 Twin Cam 96 & 103 — all models incl. police Softail · 2007–2017 Twin Cam — plus 2018–current Milwaukee-Eight, all models incl. CVO Touring · 2007–2016 Twin Cam — plus 2017–current Milwaukee-Eight, all models incl. CVO & police Trike · 2009–2016 Twin Cam — plus 2017–current Milwaukee-Eight, all models incl. CVO Pan America · 2021–current Revolution Max 1250 — all models incl. CVO

Evolution Sportster · Twin Cam · Milwaukee-Eight · Revolution Max engines.

Not covered: pre-2007, carbureted, Magneti Marelli EFI, V-Rod/VRSC and LiveWire. Twin Cam and Evolution content is verified against factory service documentation; Milwaukee-Eight and Revolution Max content is being verified against the factory manuals, and any value not yet confirmed is flagged pending verification in the app.

How It Works

1

Select Your Motorcycle

Choose your year, model family, sub-model, and engine. The app tailors diagnostics to your specific bike.

2

Describe the Problem

Pick from categories like "Won't Start," "Runs Rough," "Electrical Issue," or "Brake/Suspension" to begin.

3

Follow the Diagnostic Path

Answer simple yes/no questions. The app narrows down the cause step by step with pro tips along the way.

4

Get Your Probable Cause

Receive a clear finding with the probable cause, the component card for the part behind it, related DTCs, and the circuit diagram. When it's genuinely ambiguous, the app says so and points you to your dealer — no guessing.

5

Save and Export

Save results to your garage profile, generate a PDF report, or start a new diagnostic — all from one screen.

Ready to Diagnose?

Download V-Twin Diagnostics. Free reference tools, no account needed. No subscription. No scanner hardware to buy.

Download on the App Store Get it on Google Play

One diagnostic, $9.99 — it never expires. 3-Pack $24.99. Unlimited for a year, $59.99. One successful at-home diagnosis pays for itself several times over.