Valve adjustment - How Critical?

 I have a 2000 BMW K1200, after 5 years and 46,000 miles
a couple of valves check slightly our of spec for the
first time.

Intake valve spec is .006 -> .008
Exhaust valve spec is .010 -> .012

Checked the intake "Go NoGo" with .006 and .009 blades,
and the exhaust with .010 and .013 bades.

7 of each passed, but on one exhaust valve I had to
go up to .014 to get a "NoGo" and on one intake I had to use
.005 to get a "Go".

Since adjusting these valves involves removing the cam shafts,
ordering replacment parts, and missing another weekend or
two of riding, I'm tempted to say this is close enogh and wait
until next winter to adjust them.

You all have lots of opinions, is there a bit of leeway in valve
specs, oram iI risking a head rebuild if I wait?


Grizz

oreragfra@gqf.arg
(rot13 for email)

 
I am going to assume this engine's valvetrain is shim-under-bucket.
You're probably safe enough to continue riding it, but why all the drama?

1. Measure clearance - you've already done that.
2. Take out cams, measure shims, calculate thickness of replacement shims.
3. Pick up replacement shims at your local BMW dealership.
4. Reinstall cams.

If for some unknown reason, any BMW dealer does not have a complete stock
of valve shims, they should be stricken from the rolls of authorized BMW
dealerships, because I can't imagine making an owner wait for parts for
a routine maintenance task such as a valve adjustment.

I see from a little googling[1] that you may need a collection of special
tools to properly set the camchain tension and immobilize the camshafts.
Hopefully you already have those tools.  If not, I'd order them, and when
they come in, rip into the motor on a Friday night, then Saturday morning
head over the the BMW dealership for the shims and put the cams back in.
Less than one day off the road.

[1] http://www.bmwbobs.com/catalog/2003_catalog/K-Bike_Parts.pdf

--
Mark  '01 SV650S  '99 EX250-F13  '86 GL1200A  '81 CM400T

 Try this site as well:

http://faq.f650.com/FAQs/Valve_Shim_Change_FAQ.htm

It is for the F650, but the basics are the same.  They go into a LOT of
detail on valve adjustments for BMWs, including how to make a cam
retaining bolt.

 Also, if you measure the shim diameter you will find that many other
bikes shared the same size.  For example, my XS750 can use shims from a
KLR650 and many BMWs, since they are 29mm.

The larger diameter shims normally come in 29, 29.5, and 31mm.

 
Judging by the tight tolerances, I'd say he needs to make the
adjustments. I wouldn't take the chance of having them out of spec by
even one thousandth. A five-dollar shim is a lot cheaper than repairing
major engine damage.


Likely so, since he mentioned pulling the cams.


I agree. One torque wrench, one ratchet, one digital micrometer, and
some basic math skills are about all it takes to do the job. Plus, it's
a fun project.

__
Tim Kreitz
2003 ZX7R
2000 ZX6R
DoD #2184
http://www.timkreitz.com