“‘ _,
. ‘
SUBJECT: SUSPENSION TUNING
A motorcycle suspension system must cope with a widely variable (·,,
loading. No manufacturer can create one sus?ension setting which will
be correct for all loads. The suspension must be tailored to the
requirements of the individual rider depending upon load, riding style
accessories and their location. BMW offers factory made suspension components
to permit this adjustability in order to provide maximum comfort
and safety. All other components, i.e.: forks, steering head
bearings, frame, swingarm, wheels and tires must be in good condition
and properly adjusted before suspension modifications are attempted.
Listed below is a guideline of BMW fork parts which may be used together
for this purpose.
1 2 3
Approx. Fork Rebound
load (lbs.) Sprinq damper orifice –
150 358 STD.
w/fairing 6 358 STD.
200 358 STD.
~/fairing 358 w/spacer STD.
250 358 STD.
w/fairing 017 H.D,
300 358 w/spacer_ STD.
w/fairing 017 H.D.
350 7 017 H.D.
w/fairing 017 w/spacer H.D.
NOTES:
4
Bump damper
# of Holes
4
4
4
2
2
2
2
2
2
2
5
4
4
4
4
4
4
7
7
7
Fork Oil
Weiqht ~
or 5 w
or 5 w
or 5 w
or 5 w
or 5 w
or 5 w
1/2 w
1/2 w
1/2 w
l0W
1Load = Rider Weight+ Passenger+ Weight of Luggage and Accessories.·
In no event may gross vehicle weight exceed manufacturer’s suggested
GVWR as listed in the owner’s Manual.
2Fcrk Springs-Number indicates last three digits of part number.
Two springs are currently available:
Standard-#31 42 1 231 358-Length=567mm.-Wire Dia.= 4.0mm.
Heavy Duty-#31 42 1 232 017-Length=543mrn.-Wire Dia.=4.25rnrn.
Preload spacer #31 42 2 000 399, fitted under top spring retainer
in cases as referred to above.
Additionally, /5 models were fitted with a softer spring which is
no longer factory available, #31 42 1 230 664, which may be substituted
for #358 spring where total load is less than 150 lb.
This spring is not suitable for dual disc brake models.
3Rebound Damper Orifice-Restriction of I.D. regulates oil flow
on rebound. Two orifices are available. Part numbers:
#31 42 1 232 045 – Standard – 15.7mm. I.D.
#31 42 l 234 506 – Heavy Duty- 15.5mm. I.D.
The H.D. orifice may be identified by a groove machined around the
outer circumference.
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