A build book and service log for a single machine, a murdered-out Harley-Davidson Forty-Eight, with the factory workshop manual searchable inside it.
Everything you need to keep one bike right exists; it's just spread across a 700-page PDF nobody opens, a forum thread from 2014, a receipt in a drawer, and memory. When the question is "what torque, and when did I last do this?", none of those answer in under ten minutes.
Tetsu is a single place for one specific motorcycle: what it is, what's been done to it, what's due, and what the factory actually says.
The bike itself (specs, fluid capacities and grades, torque figures) in one reference card instead of scattered across sources of varying trust.
What's due and when, measured against real mileage rather than a vague sense that it's probably been a while.
Every job recorded with date, mileage and notes. The log is what makes the intervals meaningful, and what makes a future sale honest.
Every modification, with its part and its price. Paste an accessory link and it fills in the picture, name and price by itself. Quick-add, because friction is what stops a log being kept.
The full factory service manual as searchable text: case-insensitive full-text search across every chapter, not a PDF you scroll.
A chat grounded in this bike's data plus the relevant manual passages, so a torque figure comes out of the book rather than out of a language model's memory.
Grounding is the whole point of the chat. A general assistant will confidently give you a torque spec for the wrong model year. Tetsu retrieves the passage from the actual manual and answers from it. The difference between a plausible number and a correct one is a stripped thread.
Tetsu was rebranded away from the crew's dark-and-crimson chrome into an identity of its own. The first attempt reached for ember orange, a stylised skull and hazard stripes: the obvious motorcycle clichés. It was rejected outright.
What replaced it: black, gunmetal, brushed steel and bone, with a chrome gradient as the only thing that could be called an accent. Status colours are deliberately desaturated so they read as function, not decoration. The 鉄 character is the hero mark and the watermark. No colour. No skull.
Shipped and in use: the garage, service schedule, logbook, build book with link preview, the searchable workshop manual, photo slots, and the grounded chat. It is an installable app on a phone, which is where it gets used: standing next to the bike, not at a desk.