I'm getting ready to buy engine seals (all) and gaskets for my 1975 DT250 and while I find OEM Yamaha seals listed for sale are they ~50 yrs old or has Yamaha been producing these parts consistently so they aren't very old? I'd hate to be installing rubber seals that have sat on the shelf for that long.

Alternatives seem to be places like Disaster Motors etc

I'm not so concerned about the price more the quality of what I'm buying particularly the rubber engine seals.

Thoughts, experience, suggestions ????

I just bought some OEM seals from Yamaha. They were not that old. I’d always get OEM when possible. Same for my autos.

If you haven't already, it's good to start with any of the various online parts websites, I like partzilla, and see if the particular things you are looking for are still available or were used on other later models. Especially things like seals it's common to find out the part number was used on a golf cart or a snowmobile or something and was produced long after the application you're interested in. Then as a rule I like OEM or pro x best. My $.02

Thanks for the feedback guys. In general I also prefer OEM parts when available and my only concern here was age on the shelf for the seals.

I found all the engine seals available at Yamaha Sports Plaza in Oregon. I need to check the gaskets.

aftermarket gaskets purchased from ebay or amazon are 75% of the time "homemade" gaskets cut out with a cricut and some o-rings thrown in . So its hit or miss whether or not they used the correct gasket material. if its the correct material, and they scanned it in correctly, there would be absolutely no difference between an OEM gasket and a homemade aftermarket one. Cricut cuttes are getting cheap, real cheap. You may be able to buy one cheaper than buying gaskets.

For the gasket set I was considering the one from Disaster Motors or Yamabits. I would think they are a legit seller of properly made gaskets but.... some real world feedback would be nice.

I found all the OEM gaskets except the reed block gasket, at least so far. Also the oil pump cover gasket but that one isn't super critical.

BTW, I looked into the Cricut cutter, pretty cool unit.