Lifter and rocker wear

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Duane Ausherman
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Re: Lifter and rocker wear

Post by Duane Ausherman »

With the lifters out it is easy to examine the cam. Usually the cam is OK in my limited experience with the /5 and /6. I don't know about later models, or after these 40 years.
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Major Softie
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Re: Lifter and rocker wear

Post by Major Softie »

chasbmw wrote:If you were feeling very flush with cash then MI have these lightweight followers

http://www.motoren-israel.com/product_i ... m-4pc.html

Charles
Damn. That would certainly solve any "flush with cash" problem.
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Airbear
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Re: Lifter and rocker wear

Post by Airbear »

Thanks to all for the replies.

My current thinking is that the lifters can remain - they don't look any worse than they did 40k kms ago when I was in there last. I've had a good look at the cam lobes using a bright light and rotating the cam, and they appear to be undamaged.

For the rockers:
German ebay has a good selection of used sets from later models at reasonable prices. If I can find good ones for the 76 to 84 they will fit straight on. There are many more available for the '85 on, but that would involve some machining to the heads to fit them. I'll do some more research on that option.

The other matter is what has happened to one of the valve ends - the one that has been pounded by the worst rocker pad. On that rocker pad the hard casing has a crack in it and this has chewed the end of the valve stem. The others show the characteristic concentric marks with slight denting marks. I'm wondering whether it is possible to clean up all the valve ends somehow, so they don't damage the rocker pads on the replacement rockers. I have yet to pull the valves to check guides, so I'll hold off on that matter for now.

Thanks again for the thoughtful responses. I'll keep you informed as things proceed.
Charlie
and Brunhilde - 1974 R90/6
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George Ryals
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Re: Lifter and rocker wear

Post by George Ryals »

Any auto shop that does valve jobs has the equipment to dress thw valve stem ends.
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Airbear
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Re: Lifter and rocker wear

Post by Airbear »

George Ryals wrote:Any auto shop that does valve jobs has the equipment to dress thw valve stem ends.
Great, thanks George. That sounds easier than trying to do it myself with carpenter's tools. Grin.
Charlie
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mattcfish
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Re: Lifter and rocker wear

Post by mattcfish »

Used valve gear from 76 on can be obtained for less than $50.00 on eBay. After 76 the hardening is way better.
I upgraded my 75 rockers with early 80's gear. They bolted right on. Switch to the later style push rods while you're at it....way lighter.
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Airbear
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Re: Lifter and rocker wear

Post by Airbear »

Thanks Matt. That is the way I'm heading - got my eye on what looks like a good used set of 76 - 84 rockers.

I continued dismantling and cleaning parts today. This is the tip of the valve that was being hammered by that nasty rocker pad:

Image

It took a bit of careful filing to permit removal. Guides are still fine, and I've got a good replacement valve. A useful lesson for me. In future I'll avoid taking such shortcuts - I knew the rockers were crap back in 2008. On the bright side, at least there are no stripped studs.
Charlie
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ME 109
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Re: Lifter and rocker wear

Post by ME 109 »

Good news on the studs Charlie.
4 rockers, shafts, bearings, and blocks have been going for just under $100 on ebay. Not bad.
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hools100RS
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Re: Lifter and rocker wear

Post by hools100RS »

Hi Charlie, for what it's worth a friend had the tips of his rockers built up by a local welder using stellite rods and had them carefully re profiled using a good rocker as a pattern. They're still in his bike and have covered many thousands of trouble free kms. Replacement lifters look to be on the cards though. E bay is also a good bet. Good luck with it!! hools.
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Airbear
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Re: Lifter and rocker wear

Post by Airbear »

Thanks Hools. Good to know. Pretty sure I'm onto some good rockers.
I am getting worried about the lifters, but good ones seem hard to find. I could just assume that because of the large surface area, the abundant oil film and the cam lobes being in such good condition, that the old ones might be just fine.

Being a cheap bastard AND paranoid can be tricky sometimes.
Charlie
and Brunhilde - 1974 R90/6
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