Can a 89 kick starter be used in any year trx/atc?

[mrtwidster1]

I am working on a new engine and I want to put a 89 kickstarter shaft and gear set in it. Is the only difference the bushing? Example 88/89 no bushing  85-86 bushing? Hope this makes sense.
Are the gears the same? Is it just the cover that is different? I was told that the 86 and up was a better setup than the 85.

[sameltoe]

The gear is different and the shaft is also on the 88/89

[All250R]

The shaft and gear have a wider contact area between them on the later model setup is the main difference.