Posts
506
Joined
9/23/2014
Location
Murrieta, CA, USA
Edited Date/Time
5/9/2025 3:53pm
Howdy,
Just scored a nice 82 YZ490 for a pretty good deal. Bike runs great, but does have a small, repaired crack in the case at the kicker assembly. Wondering if different cases will fit in the frame for future restoration. Not opposed to putting a whole new bottom end together with a 5 speed if it fits. Thx
If I remember right, all YZ465 and YZ490 through 1987 are interchangeable. I had 2 465s and an 87 490 (bought with a busted kick start shaft and clutch cover) and learned how common that broken case was. Seemed the root problem was the stopper pawl on the kicker shaft would break if it kicked back too hard while starting. Later years on 490 the design/manufacturing process of the shaft was improved to eliminate breakage.
Any idea if the internals are compatible too?
best way to find out is going to Yamaha website and comparing the parts lists with diagrams to check compatibility here:
Motorcycle | Yamaha Motor Corporation, U.S.A.
YZ465 - 5 speed and helical gears between clutch and crank
YZ490 - Straight cut primary gear clutch changed in 82 but the better clutch basket was 84+. The old ones had pressed in kick starter gears while the 84+ were one piece. The better kick starters and clutch cases came out in 88 as the case had a bushing and the kicker had a one piece stop instead of the pressed on one that was prone to cracking.
Cases got a little beefier through the years but all work and are interchangeable.
There are 4 flavors of top ends. YZ465 side port heads, YZ490 side port heads, YZ490 center port 6 bolts heads and finally the YZ490 center port 7 bolt heads on the WR500.
The 82 is very similar to the YZ465 just with a minor ratio linkage system. IMO the 81 YZ465 and the 86+ YZ490 are the bikes to have.
Cut the head, dial in the carb and hold on.
Enjoy.
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