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Reaming data for valve guides?

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Micha
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Reaming data for valve guides?

Post by Micha »

Where can I find the factory instructions for this data?
I would like to get my hands on such a chart regarding tolerances of reaming new guides for a bike that lives in a warm climate.
Is this information available at all, or does a workshop perform the reaming according to some personal knowledge?
Thanks!
Michael Steinmann
R51/3 1952
Engine Nr. 529466

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jwonder
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Re: Reaming data for valve guides?

Post by jwonder »

The info you seek is at https://vintagebmw.org/library_data/Wor ... R60S69.pdf but the real answer is it’s down to feel. My comment to you is make them looser than you would expect.

I just finished my R 50/2 a month or so ago and I measured the fit with the gauges and then made them looser. Measure with a very thin oil as well to get a good feel.
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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Rodolfo850
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Re: Reaming data for valve guides?

Post by Rodolfo850 »

Im 100% agree with Jwonder comments....
I rebuilt mine R60/2 LK cylinder head, but request Machinist shop the closes tolerance, to avoid burning oil.

Yesteday after 20 milles since rebuilt on my way to the Distinguished Gentelmans Ride, my engine started to sound like a typewriter and stops...

Exhaust valve sticks to valve guide......so it returns on my trailer to house...

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jwonder
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Re: Reaming data for valve guides?

Post by jwonder »

Yes, this is becoming a problem more and more and I think guide material differs greatly. I use KPMI guides all the time and their valves if I can get them.

List of KPMI components
James Wonder
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York

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