Valve clearances

[Chris_in_BC]

My 1981 R65 owners manual shows .004" IN and .006" EX  clearances.

A buddy in town with similar age R65 shows .002" IN and .006" EX

I had never seen anything that tight for the airheads.

Latest Haynes I have (1999) shows .004" IN and .008" EX for all airheads.

Just wondering if maybe this was the setting for a 1980 model?

Chris

[Rob Valdez 79 R65]

In front of me are a riders' manual for a '79.  .004 (0.10mm) intake; .006 (0.15mm) exhaust.

My Technical Data book (MCS 022 - BMWNA MC Service Dept) says .004 and .008 (0.20mm) across the range, from /5 to 1988 and up.  (I got the book while working for a dealer in 1989).

My 1984 Haynes manual says .006 and .008.
My 1975 Clymer manual, that covers everything from /2 to 1975 900cc, also says .006 and .008.

Duane Ausherman also says .006 and .008.

My other riders' manual (for mid-generation R65s) also says .004 and .006.
I like Duane's advice (not in the above link) when he says that the gap is not so critical, as much as checking them regularly and keeping a record of mileage and dimensions before adjustment, so you can readily see any changes occurring.  


And yes, I think .002 is too tight.

[Justin B.]

Chris, this is actually in some form of literature he has ot just the way he sets them?  I really don't know if it would hurt anything as the intake valves rarely "move" very much but I don't know if an extra .004 of intake valve lift would be worth the chance.  Also, the tighter the gap, the less time the valve stays on the seat which gives it less chance to sink off some heat...

[trolle]

If you only ride in temp. above F 70 .004 and .006 will do, else I recommend a setting of .004 and .008.

If your engine was produced between 1981 and 85 new valveseats for the exhaust valves might be necessary to avoid the seats receding. A sure sign of this is when the gap keeps diminishing giving start troubles and making the engine rev uncontrollably.

just my two cents worth ...

greetings from a rainy and cold north looking forward to trying my new handlebarheaters.

trolle

[Semper Gumby]

When I started putting the .008" feeler gage in first BEFORE setting the clearence is how I found my LH exhaust valve receeding.  That and pictures of Joan's R65 was all the warning I needed.  Hi Ho, Hi Ho....

At .006" is when my idle RPM starts to float on its own at various places above 1200 rpms.  I know this now.

.004 intake .008 exhaust works year round on my 3/80 R65.