Ariel Owners Motorcycle Club

I am preparing the frame of my 1950 NH for coating and came across this number stamping on the top of the tank/forward seat fixing lug.

It reads 315 8055, it may look like a 0 at the beginning but I think this is a construction pin. Anyone seen anything like it before or any guesses what it might be?

Looks like a casting number

I haven't seen one like this before and the number sequence makes no sense to me. It isn't a casting number since those protrude from the metal instead of being stamped into the metal as this is. Does the bike have its original UK registration number or has it got "history?"

Paul, it’s a machine first registered in England, maybe been here all the time? I have a club supplied dating certificate and everything matches the factory record with a very clear frame number. I wondered if it might be an early form of security marking by a previous owner? Might have been a services number or employee number from wherever he/she worked? I agree that it’s not a casting number. Unfortunately, it has lost its original registration number so I have no history.

I think you might be right about some form of security number. The bike has obviously been stripped and repainted at some stage so perhaps the number was added then. I have seen a bike whose frame was absolutely covered in numbers like this. It had been used by an unscrupulous number dealer to acquire registration numbers which he then sold on. That loophole closed many years ago but I did wonder initially whether something of the same type applied here.

hi paul it may be a repair number if the frame has had a repair or had a works mod