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Gearbox bearing clearances

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I'm rebuilding my gearbox and at the point of assessing the mainshaft and layshaft.

The workship manual gives spec.s for the i.d.s of the various bushes and of the rolling element bearings but not for the corresponding diameters on the shafts.

Does anyone have information on the latter, or alternatively of the allowed clearances?

My micrometer measurements of my shafts imply clearances between 0.0015" and 0.0035" for the bushes, and 0.0003' and 0.0005" for the inner races of the bearings. Are these reasonable?

Also, the list of bushes includes a "layshaft bush" not further identified. Elimination suggests this must be part 04.0146, the bush within the kickstart shaft 04.0477 (items 18 and 17 in the Group 6 drawing in the parts book). I'd be glad if someone would confirm this.


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