Triumph engine numbers ce16518

Next to the number two cylinder. Just kidding by yourself an owners manual from leather up.com the $35

Need to know what numbers

Right hand rear for gearbox, off white in colour near rear engine mount.

Let's start to narrow it down.

From the number, it was made AFTER 1945 (when they started to feature a model code before the serial number), but before 1969 (Triumph changed its serial numbering system to include a two-letter prefix to denote month and year of manufacture, followed by model code and serial number).

The "H" denotes that it is a 500 twin model.

The 1961 production run ran from H18612 toH25251.
Your number falls into this range, so yes, it's a 1961, 500 cc engine, and the model of bike it came off of is called a "Trophy 500".

The F series engines are from Triumph Spitfires. FH is a 1300cc engine (1296cc) from a Spitfire Mk4. I can't remember if it's a small crank journal engine like the Herald 13/60 GE engine (good) or a large crank (not as good).

du2005 indicates it's a 1963 model, the first year of the "Unit Construction" engine (engine and transmission one unit, rather than the prior "Pre-Unit Construction engines)

1963 serial numbers run from DU101 to DU5824

The VIN is on the frame, by the steering neck (pre-1971), or a sticker near front of gas tank 1971-

The ENGINE SERIAL number is on the left hand engine case, just under the cylinder.

Then 10th digit in the vin number tells you the year.
If it is a W = 1998
X = 1999
Y = 2000
If it is a 1 = 2001
2 = 2002
etc.
So your 12/07 bike is a 2008 and the 10th digit in your vin # will be an 8