Inlet Rocker woes

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chobbler
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Inlet Rocker woes

Post by chobbler »

rocker b50 __159.jpg
rocker b50 __159.jpg (11.42 KiB) Viewed 2593 times
Half of the tiny shoulder on the inlet rocker ball end is broken off. Anybody seen that happen before? Overly pressed when made?
I don't think it's the same issue as the pushrod length problem, wrong side of the ball.
I noticed it during setting up my timing. Luckily the motor hasn't been run yet since full rebuild, so no debris to find. My guess is that it happened long ago.
I suppose it needs to be replaced with a new arm. 40-0292?
So now my nicely finished engine has to be undone in the frame again and hopefully I can tilt it enough to pull off the rocker box. Is that possible?
I thought I looked at all of the parts closely when putting it together but missed this tiny but potentially destructive breakage.
Sorry for the picture quality - phone in one hand, torch in the other.
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Re: Inlet Rocker woes

Post by minetymenace »

The ball ends are just pressed into the arms, you have to line the oil holes up and I have seen ones where the hole do not align, so either they turn or were assembled wrong. That aside there is a topic about the sockets in the pushrods being too deep and the edge of the cups hitting the rocker arm (link anyone?), this may have been the cause but who knows what has happenend in the past?
There is no evidence to support the notion that life is serious.
Abyssinian Wire-Haired Tripehounds Gnash.
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chobbler
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Re: Inlet Rocker woes

Post by chobbler »

Hi Minety hope you are doing well.
Can you buy the ball joints separate? I've seen a few NOS rockers that look a bit rough to be honest so would sooner press my own in. There's a couple at auction that look like the forging or casting has lumps out of it.
I poked a wire down both rockers oilways earlier today and to be fair the jury is out if either the inny or outy aligns!
Quality control wasn't so good.

It took me 15 years to get these spare parts up together and 2 hours before kick off there's a show stopper. Woe is me!
Lucky I just bought another Guzzi, aye! :thumb
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Re: Inlet Rocker woes

Post by minetymenace »

Long time no speak chobbler me old fruit!
If you have a BSA single, a Guzzi is a natural progression! I think all these little ball things are the same, C15 etc. there should be plenty of them about You can tell if the oil ways are lined up by blowing down the hole in the ball end....
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Abyssinian Wire-Haired Tripehounds Gnash.
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Re: Inlet Rocker woes

Post by chobbler »

Luckily I have spacers on the front and underside engine mounts, this allowed me to tilt the engine over today, just enough (with loads of cardboard on the frame tubes) to get the rocker box out.
Over half of the shoulder is missing on the inlet rocker ball, and thanks Minety, I discovered neither the inlet or exhaust rocker ball oilways line up.
So the exercise was worth doing.
Now I've got to find a couple of those little mouse hip joints on the web. If anybody has any please let me know.
And by the way, my exhaust rocker arm also has the dint where the decompressor arm digs in. I shall ignore that one and fit a return spring on the lever!
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