Kat Clutch

[kitkatman]

Busy rebuilding 1983 ish Kat engine and would like to know how much play in the springs on back plate is ok . The thinner of the springs (painted yellow) has no  end play, but turn reasonably easy. The other  larger springs has about  1 1/2 mill end play. Do I need to rebuild , or not.

[arnout]

Now you have the clutch out it seems worthwhile to fix the play. As such it isn't that serious of an issue if the play isn't excessive, mostly causing rattle noise, but it does point to the fact springs have sagged and lost some of their strength.

2 hours ago, kitkatman said:

..has about  1 1/2 mill end play..

How much is that in mm's?

The bigger the play/gap the larger the impact between parts when the load changes.

Anyway... It depends on your intended use and state of tune of the engine. For a stock road bike I'd say the quickest fix is inserting appropriately sized (stack of) washers as spacers to fill and slightly pre-tension the old springs. For a tuned or seriously used engine I'd recommend installing a complete back plate kit that includes new/stiffer springs, a thick back plate, and new dowels and rings. (Mind ordering the right ET of EFE type kit).

[Screwriverracing]

I would recommend a heavy duty back plate, on my et the standard one exploded taking out the oil pump, a little spent now could save a lot later. And the clutch will not rattle.

Cheers SRR