Help locating discontinued '98 YZ250 tranny parts - NOS preferred

Edit, sorry I have just re read your post, I am not well awake so I posted the service manual pictures. Good luck in this search.

If you have a dealer that uses light speed he can do a search for other dealers that show to have them in stock

Put a search up on ebay that sends you an email if the parts come up. Something weird about ebay I have found in regards to Yamaha part numbers is the part number needs to be chopped off in a search if it ends in zeros. So for example:

3XK-18540-01-00 SHIFT CAM ASY (92-98 YZ/WR 250) You need to search for only 3XK-18540-01 When the -00 is left on the end, nothing comes up. If you search for 3XK-18540-01 without the -00 the search shows a NOS item.

Here is the search for a new 3XK-18540-01-00 without results https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=3XK-18540-01-00&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=3XK-18540-01&LH_ItemCondition=3&rt=nc

Here is a search for 3XK-18540-01 with results https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=3XK-18540-01&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=3XK-18540-01-00&LH_ItemCondition=3&rt=nc&LH_TitleDesc=0

Here is the new shift cam from those results https://www.ebay.com/itm/GENUINE-YAMAHA-YZ250-WR250Z-91-98-GEAR-SHIFT-DRUM-CAM-ASSY-3XK-18540-01-NOS-NLA/303002168760

Here is another example of dropping -00-00 on the 4MX-17151-00-00 GEAR,5TH PINION (95-98 YZ 250) Here is a NOS part that appear in a search for 4MX-17151 https://www.ebay.com/itm/YAMAHA-YZ250-1995-1998-TRANSMISSION-GEAR-5TH-PINION-21-TOOTH-21T-4MX-17151-00/273845181773

Another thing about Yamaha part numbers is sometimes parts are compatible even if the part numbers are a little off for example sometimes XXX-YYYYY-00-00 is the same as a ZZZ-YYYYY-00-00. This front end number change is can occur when a bike model is updated drastically but that particular part stays the same. Another change that can occur with compatible parts is the end numbers may change for example XXX-YYYYY-00-00 will change to XXX-YYYYY-01-00 and the only difference between the parts will be the finish or paint color, or maybe they are Jets and one is a #150 and the other is a #160, or maybe its sprockets and one will be a 14T and the other a 15T. Be careful crossing up part numbers like this though because there are also examples where the parts are actually incompatible even though the numbers are very similar.

Maybe someone can weigh in on your bike and the compatibility of trans parts. Maybe something newer or older will work. That will broaden what parts you can search for. Good luck.

Try speed and sport.
http://www.speedandsportinc.com/

The searches you're doing on ebay may be way too specific. People who are parting these things out are seldom going to know the part numbers.

Get more generic in your searches. Look for '1998 YZ250 transmission', or even just 'YZ250 transmission' and filter out everything you don't want.

The parts you need will be on ebay at some point if they aren't now.

I part out old bikes & engines. I'm sure I've had these parts at some point. However, I and many, sell the whole transmission as one assembly. It is simply too tedious to list the transmission piece by piece (at least for me).

Sure these are even discontinued? I popped them into an OEM search and usually there's a note for a discontinued part. These show right up. Check Worldofpowersports.com

Giving me flashbacks to spring of '98 when my '97 tranny bit the dust after maybe 30 hours. The main culprit was the 3rd wheel gear! Yamaha who I have been loyal to going back to the late '70's had an issue with that part but never publicly admitted. Many of us had similar issues. Not sure if those parts are still produced. I will say that you need to check the tolerances on the entire trans. A mechanic buddy of mine missed a slightly bent shaft and we had to split the cases 2x. The '98 had the same bottom end and the 3rd wheel gear on that one looked stronger and performed better. I sold my '97 after the 2nd case split, bought a low hour '98 and rode/raced it for two years w/out incident. My '97 ran in the woods (w/the upgraded part) at least 3 seasons with the guy I sold it to

That was a great handling bike

Try some major city run by Democrats if you are looking for tranny parts...

My first YZ,been a Yamaha guy ever since...