Do R65 valves fail?

[gregb]

Hi all. I have an 85 R65 with 75,000 km on it and which is pretty much faultless. I love it.

Just returned from a 3,000 km trip, on which two separate people admiring the beast told me something worrying. Both said they had one which threw a valve. One said it was recommended to renew valves at 50k, which is news to me.

I haven’t seen any real change in valve clearances but that probably doesn’t mean much if they decide to let go suddenly.

So is this something to consider or just bad luck in their cases? I don’t have any other reason to remove heads so would rather not. Thanks for any advice. Greg
(Photo just to prove the bike exists. )

[georgesgiralt]

Hello,
I've run more than 300 000 km on my 1982 R65.
I was lucky enough not to have any valve fail. But I had valve springs fail on me and, thus, forced dismantling only to find that the valves where shot.
Where I live, it is common wisdom to replace valves (and guides) around 120 000 km.
The valve stem on the R65 are thinner than the other model ones. So that may explain the lower duration ??
If I were you, I will start saving in order to have the money available when the bike reach 100 000 km and, then, plan for the job.
Bear in mind that if you are not the first owner of the bike, the mileage on the clock may not be the real one.. (my bike had 3 different clocks in its life so telling how much km she ran need some calculation...  and now, the clock shows 7400 km ;-)   ) ....

[gregb]

300k! - that is impressive - well done. The 100-120k head overhaul does sound more sensible so I will stop worrying and keep riding. Thanks for your reply.

[Bob_Roller]

The '81 model year bikes R65, R80, and R100. Had valve seat issues the alloy for the seats was new and the unintentional consequence was the seat did not transfer heat from the valve to the cylinder head . Valve failure was common . I've got an '81 R65 and had valves replaced at 45,000 miles . The valve face should have three angles, mine were worn knife edge thin . I had a shop replace the seats use stainless valves that were 2 mm wider and 1mm thicker stem . That was 38 years ago no valve issues since .

[Tony Smith]

 The valves in R65s can, and do fail. There are lots of theories, some of which I think are plausible and some I think are fantasy.

In the end it doesn't matter the trick is to avoid it happening.

My reckoning is that valve to guide clearance should be checked regularly. Unfortunately this can only be done with the head removed but rings should be replaced around every 40k km so that presents an opportunity.

I prefer not to renew guides, the prospect of accidentally broaching the guide bore requiring expensive rectification deters me.

I have my guides k-lined, an inexpensive process that lasts as well, of not better, than new guides.

The BMW OEM valves are good, but Intervalve are better (and cheaper). Motobins carries them.

I reckon on replacing valves after 50k km.

I have attached a photo from my personal black museum, my bike's previous owner is as deaf as a post, throw into the mix he had been having coil problems.

When the valve dropped he assumed the loss of power was ignition and rode 20km home on one cylinder.

If this piston doesn't give you nightmares you have no mechanical sympathy.

[gregb]

Thanks Bob and Tony for your replies.  BMW made a lot of changes and it’s hard to keep up. Anyway, I don’t like the look of that piston so perhaps it’s time to either pull the heads and barrels… or sell.  Will keep riding for now.

[Steve]

At 177,000 miles, no valve problems thus far.