The owner of "hobby business" Redfern Motor Parts in Corrimal is selling the building and decided it was easier to auction off his collection rather than move.

But its not a sad time for Mr Blain - he's actually been enjoying spending the last few months sorting his collection into more than 1300 different lots.

It helps that he is moving into an apartment and simply wouldn't have space to keep the collection at home.

"I don't know you can keep everything forever," Mr Blain said.

"As we close this store we open up the doors for others around the world.

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"When you go to shift houses, it's a formidable task, - you'll go and find things you forgot you had. And that's been the case here. It's been a bit of a reincarnation of stuff that had been covered. It's been quite good, the stuff that's come out."

While he is keeping some spare parts to keep his own motorcycles running, items like cycles, parts, pins, posters, signs will go under the hammer.

He bought the business in 2000 after retiring and and relocated it to Corrimal.

"I've always had motorcycle oil in the veins and I don't think you ever get rid of it if you're into bikes," he said.

"I've got a couple of modern bikes as well but my passion has always been the old ones."

The online auction will take place over three days from May 3 to 5 at www.manshedauctions.com.au

A pre-auction viewing will be held at Redfern Motor Parts on Saturday between 10am to 5pm.