Scale bv bleed area
 f) Scale
& bleed areas to a KYB DFF 12.5 rod for comparison
 
bv 1
stk rod
stk bld =
bv 2
stk rod
stk bld =
  Scale bleed areas to KYB DFF 12.5
  0 mm2 scld to 12.5 rod
  0 mm2 scld to 12.5 rod
  • As a general rule, default bv comp clickers are about in the middle of the range.
    • For example, (2151f) 2013 YZ 250, default bv clicker is:  
      bc-10 which =  1.18 mm2  flow area at that clicker position
  • For a quick comparison, we have scaled the bv stem cHole on the bikes below
    to the equivalent of KYB DFF 12.5 rod.
  • The purpose is then to find each forks bc-clicker setting that most closely
    matches 1.18 mm2  (highlighted in yellow below).
  • This gives a bv clicker setting and flow area that is comparable between all bikes.
  • The click range flow area factor is 1.30    (1.18 x 1.3 = 1.51)  (1.18 / 1.3 = .93).
    • We are making the assumption that 130% is a reasonable range of adjustment with 6-8 clicks available in either direction.
  • [The values below are fixed and do not change]
  rec_id
ftype
 mm2 low/high %  bv click
1638f   04 RM 250    12 rod
bc-6 is close to 1.18 mm2,
but gives a limited
click range of  4 - 6 - 8
Showa DFF
   2.60 stk chole dia (5.3 mm2)
   2.50 bott ndl dia (4.9 mm2)
     5.3 - 4.9 = .40 mm2 diff *
.98 [aver 160%] bc-4
1.24   bc-6
1.50 153% bc-8
3531f   10 CRF 250    12.5 rod
The cHole is much larger than the
bott ndl dia resulting in 2.17 mm2
flow at bc-1
Showa DFF
   2.40 stk chole dia
   1.75 bott ndl dia
     2.11 mm2 area diff *
2.17   bc-1
2.63   bc-10
3.04 140% bc-20
3791f   10 CRF SC 250   12.5 rod
With a 1.95 mm insert,
bc-12 is close to 1.18 mm2
with a good click range of  6 - 12 - 20
Showa DFF
   1.95 mod insert
   1.75 bott ndl dia
     .58 mm2 area diff
.89   bc-6
1.19   bc-12
1.54 173% bc-20
3253f   15 XCF 350    8 rod
The 4CS kit needle was designed to
work with the 8mm rod, but gives a
fairly tight click range of  15 - 20 - 26
4CS DFF
   1.78 mod chole dia 4CS kit
   1.77 bott ndl dia
    . 03 mm2 area diff
.93   bc-15
1.20   bc-20
1.51 163% bc-26
3509f   19 SXF 350    12 rod
As per below, we should just use the
stk bv stem cHole and set default
bc-12
AER SFF
   2.04 stk chole dia
   1.91 bott ndl dia
     .40 mm2 area diff
.90   bc-6
1.19   bc-12
1.56 173% bc-20
3509f   19 SXF 350    12 rod
We have used 1.95 insert w/bc-16,
now it looks like we should have set
to bc-21, or used stk cHole above
AER SFF
   1.95 mod insert
   1.91 bott ndl dia
     .12 mm2 area diff
.90   bc-15
1.18   bc-21
1.51 168% bc-29
2151f   13 YZ 250    12.5 rod
Baseline for comparison
We are simply using this as a
fixed point to compare against
KYB DFF
   2.07 stk chole dia
   1.80 bott ndl dia
     .83 mm2 area diff *
.93   bc-3
1.18   bc-10
1.51 162% bc-20
4108f   22 CRF 450   14 rod
The cHole is larger than bott ndl dia,
resulting in 2.25 mm2 flow at bc-1
Stk, there is minimal adjustment of
11% above and below default bc-8
Showa SFF
   2.42 stk chole dia
   1.53 bott ndl dia
     2.77 mm2 area diff
2.25   bc-1
2.50   bc-8
2.75 122% bc-16 max
4108f   22 CRF 450   14 rod
We tested 1.99mm insert, but found
that 1.95 as per below gives a better
default clicker setting
Showa SFF
   1.99 mod insert
   1.525 bott ndl dia
1.06   bc-1
1.17   bc-4
1.56 147% bc-16
4108f   22 CRF 450   14 rod
Proposed with reasonable click
click range of 1 - 7 - 16
Note there are only 16 clicks max
Showa SFF
   1.95 proposed insert
   1.525 bott ndl dia
.91   bc-1
1.17   bc-7
1.46 153% bc-16 max