Research methodology
IronHead research methodology
The standards, sources, and verification steps behind every IronHead guide. The research team treats the catalog as a living document — each model entry is reviewed against primary service-manual data, period-correct supplier literature, and teardown evidence from owner-restored examples before the guide ships, then re-checked on a quarterly cadence so year-coverage and torque specs stay aligned with how the motorcycles actually come apart on a shop bench.
Research sources
Primary sources
Where the underlying facts come from.
Every guide starts from the factory service manual for the model — not a third-party reprint. Where the manufacturer still publishes parts books, dealer service bulletins, and owners-club technical advisories, those are folded in next. For pre-OEM years (where no complete manual survives), the team cross-references period dealer-service training material and the model’s documented service-history corrections against multiple independent restorations.
How a model is scored
The four-axis rubric the shortlist runs through.
Candidate models are scored across four axes: documentation depth (how complete the surviving service material is), restoration frequency (how often the model shows up in active shop queues), parts availability (whether the supply chain supports a first-time restorer, not just a marque specialist), and coverage gap (whether an existing authoritative guide already serves the same audience). Models with a combined score above the cutoff enter the active shortlist at /research/next-models.
Verification & torque-spec provenance
Why a stated torque number is the stated torque number.
Every torque value in the guide cites the source document and section (manual page, bulletin number, year-applicability window). When the factory value conflicts with later service-bulletin updates, the guide lists both and explains when each applies. The team rejects any torque figure that can’t be traced to a named primary source — unsourced forum consensus is excluded by policy, even when it matches observed practice.
Update cadence & corrections
How published guides stay accurate over time.
Each guide is re-verified against the latest sources every quarter. Corrections flow back into the PDF and the per-model page on the next deploy — buyers receive lifetime updates on every purchase, so an early copy of a guide picks up later corrections automatically. Reader-submitted corrections are triaged against the same primary-source standard before they ship.
Known limitations
The methodology is intentionally conservative. A guide ships only when the primary-source evidence is sufficient to defend every torque value, every year boundary, and every wiring-diagram pinout against challenge — which means some candidate models stay on the shortlist longer than buyers would like. Models with incomplete surviving documentation, single-source torque data, or no independent restoration corroboration wait until the evidence base improves, even when reader demand is high.