Next Question! 500 Sprocket Carrier

[Trigger]

Great explanation and advice everybody - I always change cush drive rubbers normally (which is why I was trying to get sprocket carrier off). Now I have to figure out how to get it off!
If the seizure is between the inner vertical face of the sprocket carrier and the hub centre (where the cush drive rubber nipples stick through into the brake area)? Is that where I should apply heat?
K2-K6 - no, unfortunately I haven't got access to a slide hammer but will make some kind of jig

Just looled at schematics and see now the area of seizure and hence where to apply the heat.
Ironically (and don't shout at me!) I think I threw a spocket carrier away (I think, as I can't find it in the shed) that may have been off a 500 - as I built the CR750 Rep from parts and bought a sprocket carrier that by the time I got round to fitting it, realised it wasn't for a 750 but didn't know what bike it was for - was kicking around for years in the shed and got naffed of with all the mess in the shed so sold and binned loads of parts last year - hindsight!

You need a sprocket cover Phil. It has a seal in the middle and a large 0'ring to keep the shite out.

[philward]

I have the sprocket cover Graham - just re-zinc'ed it yesterday

[Trigger]

I have the sprocket cover Graham - just re-zinc'ed it yesterday

Sorry Phil, I thought you said, you throw it away but, you were on about the carrier 

[philward]

Success - bit of heat, lump hammer tapping against sprocket (oppisite direction) then bang against old sprocket teeth using large bar through spokes - then it popped out. Phew!
The carrier looks oily on the surface that normally seizes - does that looks ok?

[deltarider]

Looks much and much better than mine. No comparison.

[philward]

Now we have direct comparison, I can clearly see what the potential issue was.
Just for the benefit of anybody having a seized carrier and doesn't come off as easily as mine, I was going to bolt a plate across the sprocket (effectively blanking off the hole in the centre of the sprocket/carrier) then lay wheel carrier facing down across 2 blocks across the wheel rims. Then you could drive the plate downwards from brake drum side using a bar and hammer - this would allow even pressure to be applied to the carrier - similar to K2-K6's suggestion about slide hammer. Hope thats helpful to someone unfortunate enough to have a seized carrier.
One again, thanks for everyones help.

[Trigger]

A new one is 78.50mm  Put the carrier back on the hub after a clean and without the rubbers, put the bearing retainer back it and see how much play you have. Looks OK to me Phil but this is one way to test.

[philward]

Sorry for delay - I've been 'hub polishing'. I'll measure up and check. I can't really see any visual wear - and brake liner is not cracked! So happy ending to what I thought would be a expensive day of hassle.

[philward]

Seems in size Graham

[K2-K6]

At risked being called a blasphemist, but... if mine were stuck, hm, I might leave it as it is. Surely, I'll miss some (minor) damping, but aren't there a lot of bikes out there, that lack this damping there altogether? I mean, look it from the bright side: your rear wheel will be a lot easier to balance dynamically than standard (practically impossible). Never understood why Honda designed it this way. Has the same design been applied on other Honda's?

The 750 certainly uses a different arrangement with the sprocket carrier having it's own, and independent, bearing outlying from the two wheel bearings. It's tightened as an assembly with spacers to make a "whole wheel " module but significantly larger and heavier than the 500 fitment.

I feel if you're to consider the effects of these cush drives you may ultimately hold a different view as to their effectiveness.  Each one is dedicated to reduction of peak load spikes and not transfer those destructive forces further along the transmission components, that's in both directions.  They are vital to the installed systems running within design parameters in regard to component loading and longevity. Virtually all road (possibly not some competition machinery) vehicles use them for this purpose, to maintain component life expectations in service.
These 500 sohc based designs show clearly the most at risk component (primary drive chain) when taken apart.  Even if the rest of the engine is in very good order from being serviced correctly,  this one thing will be worn almost without exception.  In effect it virtually proves there's conditions close to the limit for this part And that's assuming the cushes are good condition.
If they are wrong or compromised, then component life will be reduced. In extreme cases it can ultimately destroy the crankshaft, not necessarily in this engine,  but illustrative of it's potency if uncontrolled vibrations are left to run out of control.

The primary chain,  Hi-vo type could probably utilise it's own thread here to fully understand it.

[Bryanj]

The theory is that Hy Vo chains "climb" the gear teeth and so self tension, problem with the 500 is honda didnt design in enough clearance to the oil gallery, 550 is a bit better but still hits.