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Old 05-29-2012, 02:59 PM   #79
FJ_Kevin OP
Gnarly Adventurer
Joined: Dec 2010
Location: Maryland ==> originally from Long Island
Oddometer: 365
OK, back to it!

Clutch: In addition to examining clutch components between my parts motors I also put together a table of part numbers to determine interchange of the major clutch components across the various model years of the 465 and 490's. Even though part numbers are different in some cases, these components can be swapped so long as you swap them as a group.

For instance, the 80/81 clutch basket uses a helical cut gear while the 490 baskets use straight cut gears. You can use the 490 basket on the 465 so long as you also use the corresponding primary gear on the crankshaft.

There are several significant improvements made in the 490 clutch baskets (notice the 4 different part numbers across the 465/490 range) . The photo below shows 3 basket styles I have on hand. These are a 465 (top), 82 490 (left) and a 83 490 (right).

Notice that all of these clutch backets have a (small) gear on the back side that engages with the kick start idle gear. On the 465 and 82 490, this gear is pressed on. This seems to be a weak design as the press fit is not strong enough to prevent movement in relation to the basket. You can also see differences in the riveting and in the machining of the large gear. I did not weigh them but it appears (due to amount of machining) the 465 basket is heaviest andthe 83 490 basket is lightest.

The top side of the baskets is shown next. The 490 baskets (on the bottom) have more fingers then the 465 basket and so the fiber clutch plates are not interchangable between 465 and 490. The 490 baskets had much less ridging in the aluminum fingers compared to the two 465 baskets I looked at. This seems to be another good reason to go with the 490 basket.

But I think the the more compelling reason to choose the 1983 490 or later basket is the pressed kick gear issue.

This photo show the 465 (and 82 490) kick gear problem. The pressed gear has rotated and pushed away from the basket. It actually wore the machined slot open over time. The pushed out gear spaces the clutch basket out form the clutch bearing it sits against. This then prevents the clutch primary gear from lining up properly with the primary gear on the crankshaft. This offset in the gears is what led me to take a closer look.

This next photo is the 82 490 basket. It also has a pressed on kick gear but this basket is in good shape.

The problem is solved once and for all on the 83 and later 490 basket where the kick gear is machined as part of the large clutch primary gear.

More to come....

So can anyone put a date on these hi-point boots I just picked up?

My '81 YZ465 Factory Race Replica

My Vintage Husqvarna/Motocross Restoration Extravaganza Thread
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