Is it possible to remove thru the top with out splitting the engine off? This is a early one. Opps that is the Clutch Brake.

I believe the proper way to service the clutch brake would be to split the engine from the transmission, remove the shift interlock lever from the top of the clutch fork, then remove the clutch assembly from the input shaft allowing the clutch fork to pivot forwards and out of your way. The clutch brake consists of two halves that are bolted around the input shaft. Each half has its own friction shoe riveted to it that the clutch's center hub contacts when the lever is pushed forward.

I can't say if it's possible to remove the brake shoes without doing all that, I've never tried. The access cover on top of the transmission allows for a good view of these components but isn't very big to work through. If the nuts that hold the brake shoes to the housing can somehow be removed without interference it may be possible but it wouldn't be very fun to attempt.

If the clutch brake isn't working there are a few things I have seen that can be the cause.
-Friction shoes worn, loose, or detached from the backing plates.
-Wear in the clutch fork, release collar, or center hub causing too much play in the system to put pressure on the brake.
-Very low transmission fluid level, allows the gears to spin too easily while in neutral making it difficult to slow them down to engage gears.
-Excessive oil on the shoes.
-Clutch disc not fully disengaging due to improper adjustment or wear.