Kakugo Messages: 7039 Registered: August 2003 Location: Selling Souls at the Side...
(18) Geoff Duke
That "deflation problem" was pretty common with 80's Japanese trail bikes, in the specific those using DID-manufactured wheel rims.
As the rim aged there was a pretty high chance it developed some corrosion on the inside which rubbed against the tube causing loss of pressure and in the long run hard to explain punctures. It wasn't that easy to spot that corrosion: it usually required a magnifying glass and some sensible fingers. If corrosion damage was already visible on the naked eye the rim was usually already only good for the scrapyard.