Worn valve guides (again)

[Duane Ausherman]

Garnet, so not only must I decide which church to not attend, now I must go back and decide which bikes to not fix. My head hurts, so now I have to decide which drug to not take. Some are easy as they have many reasons to not take them.

[Woodgrain]

Could you be missing the underlying issue.Is it possible that the metallurgy of the two materials is incompatible. Amco 45 valve guides and BMW valves apparently are not very compatible.Accelerated wear occurs with the bronze guides.Cast iron valve guides are the way to go with stock valves. This info is from an individual far more versed in the black arts of BMW repair than myself.

Woodgrain

[hzbloke]

I was wondering the same thing: perhaps the valves and guides are a mismatch? But how do you know before you install them? The one that wore so quicky was a genuine BMW guide with an Intervalves valve. I don't know what the previous setup was - it could easily have been all original BMW. I seem to remember Snowbum saying he didn't like BMW guides but I'm not sure why. Because I didn't think too hard about it I've (stupidly?) put the same combination back in. I'll let you know in another 30,000km how they're wearing.