Bike Manufacturing Date by Chassis Number: What It Shows

A bike chassis number tells you who built the bike and its model year. It does not tell you the month. If you need the exact month, read the month and year of manufacture on the RC or on Form 22 from the manufacturer.

This guide covers 17-character chassis numbers on bikes and scooters sold in India from about 2010 onward. You can paste one into the VIN decoder to get the maker and model year in one step.

The Short Answer

Count the characters of the chassis number from the left. Character 10 is the year letter. Look it up in the table below and you have the model year.

For the month, stop decoding and open the RC. The registration certificate has a field for month and year of manufacture. On a new bike, the same date appears on Form 22, which the manufacturer issues before registration.

Many forum posts claim a fixed letter for the month. We found no published month table from BIS, Hero MotoCorp, Honda, Bajaj, TVS or Royal Enfield. A letter that matches the month on one bike can be a model code on another.

Characters 1 to 3: Which Maker Built the Bike

The first three characters are the World Manufacturer Identifier. India's prefixes start with M. These are the common two-wheeler prefixes our decoder recognises:

If the prefix on the frame does not match the brand on the tank, stop and ask why. It can be an honest mistake in a listing. It can also be a frame that does not belong to the bike.

Character 10: The Model-Year Letter

Character 10 follows the international year cycle. The letters I, O, Q, U and Z are never used, and the cycle repeats every 30 years.

Model year and build year can differ. A bike assembled in November 2025 may carry the letter T for 2026. That is normal and does not mean the seller is lying. It is the reason the RC date matters more than the letter.

Take an illustrative chassis number, MBLHAR123S1234567. The prefix MBL points to Hero MotoCorp. Character 10 is S, so the model year is 2025. This string is made up to show the counting. It is not a real bike.

Characters 11 to 17: Plant and Serial

Character 11 is usually the assembly plant. Most makers do not publish their plant letters in India. Royal Enfield is an exception, because it filed its decoding with the US regulator to sell bikes there:

Characters 12 to 17 are the production serial. A higher serial means a later bike within the same model and plant. It does not convert to a date.

Where the Month of Manufacture Is Recorded

Three records carry the month. Use them in this order:

1. The RC. The registration certificate format has a field for month and year of manufacture. A smart card RC and the DigiLocker copy show the same field.
2. Form 22. The manufacturer issues this road-worthiness certificate for a new bike. It lists the chassis number, engine number and manufacturing month.
3. The frame or certification plate. Some bikes carry a riveted plate or sticker with the month and year. Not every model has one, and a sticker can be replaced.

Our bike RC check guide explains how to pull the RC details online for a registered bike.

New Bike vs Used Bike: What to Check

Buying new. Ask the dealer for Form 22 before you pay the balance. Match the chassis number on the form to the stamp on the frame. If the month is older than you expected, ask for a newer unit or a discount in writing. A bike that sat in stock for a year still gets a fresh registration date, so the RC will not hide its age.

Buying used. Read the RC first. Then find the stamp on the frame, usually on the steering head or the right side of the frame near the engine. Check that every character matches the RC. Clear paint around the stamp and a crisp, even font are good signs. Fresh welding, filed metal or uneven characters are reasons to walk away.

Checking for recalls or imports. For bikes sold in the US, our motorcycle VIN decoder guide covers recall lookups. Indian-market bikes do not appear in that US database.