Valve setting 100cs 1981

blackbeauty

New member

• Sep 24, 2012

• #1

100cs 1981. Valve settings?
Doing my 30k all fluid service and preparing to set intake & exhaust clearance. I've got a new Clymer (10&20mm) and a real old Clymer (15&20mm) along with the original booklet that indicates after break in (10 & 15mm). I'm thinking of following the old booklet with intake of 10 and exhaust of 15mm. Why all the in consistency from one edition of the same book and then the factory booklet? Is there any advantages to one of these setting over the other?

Thanks,
Herb

 

N

NORTHCOUNTRY

Guest

• Sep 24, 2012

• #2

Herb; I'd go with new Clymer due to the gas we have to use. Also my 1977 100/7 runs a little cooler with intake at 15. Can't really say why but after the first 150,000 miles I'm not gonna change it.
Also Have to admit to owning a Oil Head Rt and like the comfort for 2 up but there is nothing better than an airhead when out on the road alone.

 

N

NORTHCOUNTRY

Guest

• Sep 24, 2012

• #3

Herb; Sorry.... should have said 'Old Clymer.' I'd go 15 intake and 20 exhaust. Been doing it since 1978 on my 100/7.

 

B

bikerfish1100

New member

• Sep 24, 2012

• #4

ticky valves are happy valves. use the 15/20 setting.

 

mikegates

Total Freak

• Sep 25, 2012

• #5

loud vales save lives

 

C

cycleman2

Bluenoser

• Sep 25, 2012

• #6

oldbeemer said:

Herb; Sorry.... should have said 'Old Clymer.' I'd go 15 intake and 20 exhaust. Been doing it since 1978 on my 100/7.

Click to expand...

This is what my R75/6 owners manual recommends. 6 & 8 Thous or 15 & 20 mm, whichever suits your fancy. Most of us in this neck of the woods use these gaps for the valves.

 

lmo1131

New member

• Sep 25, 2012

• #7

mmm mmm .... 20mm is almost an INCH.

Methinks you're referring to .15mm (.006") and .20mm (.008")

+1 on Noisy valves save lives!

 

pglaves

#13338

• Sep 25, 2012

• #8

Lmo1131 said:

mmm mmm .... 20mm is almost an INCH.

Methinks you're referring to .15mm (.006") and .20mm (.008")

+1 on Noisy valves save lives!

Click to expand...

BMW changed the spec at least twice.

Early airheads were specified at .10mm (.004") and .15mm (.006")

Later airheads were then specified at .15mm (.006") and .20mm (.008")

Later the latter specification .15mm (.006") and .20mm (.008") was back applied to the earlier bikes.

When Oak Okleshen rebuilt a set of heads for me he advised .006" intakes and .010" exhausts for the first several thousand miles - then .006" and .008" would be OK.

 

blackbeauty

New member

• Sep 25, 2012

• #9

Intake & exhaust settings

Guys,

Thanks for all the feedback and sharing the expertise. I'm going with the .15mm intake & .20mm exhaust settings as most suggest.