Alright, things have finally settled down after recovering my two YZ465
so I am now ready to refocus and continue on documenting the rebuild process started many months ago.
Recall from earlier posts that the transmission has been reassembled and I had decided to assemble the rest of the motor using,
- 5-speed yz465 gear set
- 1985 YZ490 engine cases with offset clutch actuating arm bore
- The YZ465 clutch basket with helical cut gear
- The corresponding helical primary gear for the crank
- YZ465 crank and cylinder
Remember that using the late model engine cases requires I use the YZ490 clutch pressure plate too. This plate has a longer adjuster bolt that helpd make up for the offset in the clutch arm bore. Unfortunately you cannot simply swap the adjuster bolt into the yz465 pleasure plate as there is a difference in the casting that prevents this.
I would have used the improved YZ490 straight cut basket as discussed previously but I did not have an extra straight cut primary gear at the time of assembly (although I do have one now).
Here is one last photo of case comparisons that I did not post yet.
I think the point of this one was to further show the difference in case venting between the early yz465 cases and later 490 cases. It also shows compares the casting numbers I found across various serial numbers.
One final point is the difference in the early and later style clutch (pinion) shaft bearing. The early bearing is unsealed. For some reason they switched over the an internally lubricated sealed bearing. Perhaps this was to keep gear teeth shavings out of the bearing? I noticed Yamaha also moved to a sealed bearing behind the counter shaft sprocket as well.