Rocker Shaft

[beno9962]

Opinions on this rocker shaft out of my 948cc?

I notice the grooves where the rocker arms go are identical to those in each corresponding rocker bush, so I assume this is for oil as opposed to being worn?

Pictures below...[frame][/frame][frame][/frame][frame][/frame][frame][/frame]

[chrisryder]

Nope, that's worn.

The raised bits in the middle of each one are because there's a groove in the bush in the rocker to allow oil to flow around the shaft. But the shaft's are perfectly plain (except for oil holes) when new. You've got this far to have it all apart. I'd replace the shaft while it's out.

Are you sure there was oil getting to the rockers? The 'pedestal' with a hole through must be fitted above the hole in the head where the oil feeds the rockers.

[beno9962]

Thanks Chris, yes it's quite likely that it's been run without oil getting to the bush. When I bought the engine, it had little or no oil in it. Do you think it's worth replacing the rocker assembly as a hole? Judging by the depth of wear, I guess there's gona be a fair bit of play in the bush.

[beno9962]

Scrap the last comment, looks like it's going to cost about £60 for a new rocker assembly. Seems like it costs around £10 for a new shaft, and new bushes £1.25 each.

Anyone got any ideas how I'd go about removing the bushes and reinstalling new ones? Assuming a new bush is needed....

[chrisryder]

When I rebuilt mine, I just replaced the shaft. So can't comment on replacing bushes...

I imagine you can use a new bush and squeeze it in a vice into the rocker to push out the old bush. You'd need a socket on the other side of the rocker to give the old bush somewhere to go to.

Apparently you have to ream the bushes to the perfect size when fitted, as they get a bit smaller once squeezed in. Not sure how necessary that is, you'd soon find out when it came to putting them on the shaft though.

[beno9962]

Thank chris, Yes, looked into it a bit more and sounds like a new shaft will suffice. I'll just have check there's no play in the rockers when I re-fit.

[chrisryder]

See if there's play in the rockers on an unworn bit of your existing shaft? Should give you a rough idea.

[bmcecosse]

That's quite the worst rocker shaft wear I have ever seen! I can't see how the rockers won't be worn too - but no harm in trying them.

[IslipMinor]

When you reassemble the new rocker shaft, make sure that the rocker pillar with the oil feed is in line with the oil feed hole in the head.

[MarkyB]

Is the head still on the engine?
I'd take the plugs and push rods out if it is, and spin the engine over to make sure the oil passage isn't blocked.
The hardening on these parts is very thin which is fine in normal service i.e. in the presence of oil!
I've got better shafts knocking about and I suspect a lot of owners do, save some money and put a wanted ad on the site.

[bmcecosse]

Plenty on ebay - shafts, and complete assemblies.......

[beno9962]

Incredibily, very litte wear on the rocker. Just had to buy a new shaft. I think one of the oil holes was blocked but all cleaned out now.

[bmcecosse]

Great success! Just make sure - as Richard has pointed out - that the oil feed pillar is in the right place on the shaft.