We get a lot of requests for bearings for engines that have been out of production for a long time. Many of these engines, such as the older OS .60 and .61, use bearings specially made for them and the bearing suppliers we use do not make them. We can have them made special but the manufacturers require minimum orders for these that are usually 10,000 bearings! Needless to say, we can't afford to have 10,000 bearings made for us and have them sit on the shelf for decades! Your best option for these engines is to bite the bullet and go direct to the engine manufacturer for these bearings.That said, we have no idea why a manufacturer chooses to increase their production and parts cost needlessly like that. Most of these special size bearings are only 1mm different in one dimension (sometimes small fractions of a mm in the case of Novarossi) from the standard bearing they come from. The standard sizes have proven quite adequate for model engines.
Continue to give us a shout if you have an engine we don't list. Chances are, we have the bearings but have not listed that particular engine.