Cant engage reverse with engine running

[DonaldMHM]

Hello all, new member here with a 1978 Caterham 7 with a Lotus TwinCam engine.

Reverse has always been a bit tricky, when my father owned the car and in my ownership, but it has now got to the point where, with the engine running, it is nigh on impossible - when trying to engage something is still spinning so there is a grating noise. The only solution I have been able to find is to turn the car off, engage reverse, start with clutch in and use reverse this way, even then one has to hold down the lever or it jumps out of gear. Is this a known problem with a simple solution?

Thanks

[gjz30075]

No problems with first? If so, I'd say the clutch isn't disengaging fully, or the input shaft is binding in the
bushing/bearing in the crank.

[DonaldMHM]

First perhaps a little stiffer than it has been but no major problems, can always get it. Feels a bit down on speed so could well be a bit of clutch slip - new clutch <1000miles ago, easiest way to check for this?

[AHM]

With the cluth disengaged, put it into a forward gear to stop the gearbox then straight into reverse - should go without a crunch.

Also check the adjustment in the clutch rod.