Untitled Document

Fk Valving	Sh Valving	Fk Dyno	Sh Dyno	Compare Dyno	Fk Info	Sh Info	List of Fork Records	List of Shock Records	List of Fork Dyno Tests	List of Shock Dyno Tests

2010 CRF 250 (3295) [334]

fk dim 05 - bv needle

scroll down for needle and seat flow area

click [additional info] below image

bv needle
USD DFF SHOWA TC

The vlpn for bv needle includes:
- needle [dimens a-d]
- thread pitch, clicks [dimens e-f]
- comp hole nBit [dimens n-o]

vlpn [bi_vlpn_fbvndl]

SF.BVNDL35.250H10

done

sdpn

[fbvndl dimens from]

2010 CRF 250

a [top needle dia] [.00]

1.436

b [taper ht] [.0]

3.0

c [bott needle dia] [.0]

1.75

d [needle taper]

3.0 °

e [thread pitch]
[actual / relative]

.75a

f [clicks per turn]

g [end/last click]

n [comp hole nBit] [no mm]
[from fk dim 04 'u']

#42

o [comp hole dia] [.0]

1.93

p [oring dimens th x id]

1.5 x 2.5

q [oall needle ht]

139.75

[comments]
The 10crf250 bv needle is 7mm shorter than the 11-14, so they get different vlpn. However, the needle taper and flow area is the same.

We are using this bv stem in Showa spr conv.
The 10-14crf250 hole area is 2.40mm dia resulting in too much flow area. We install an insert that reduces hole to 1.93mm.

stk hole dia = 2.40 [#42 fits loose]
mod hole dia = 1.93

Untitled Document

Record count 1 for bv needle
List of bikes with this part from bikeinfo table.
id's	bike
(883) [334] USD DFF SHOWA TC	2010 CRF 250

Untitled Document 2010 CRF 250
USD DFF SHOWA TC
not WP, this comment only pertains to WP forks

[bv needle img 240 x 420]

SF.BVNDL35.250H10

[additional info]

Untitled Document SHOWA bikes that have [additional info]
SF.BVNDL35.250K14
SF.BVNDL39.250H15
SF.BVNDL3325.450S06
SF.BVNDL35.250H11
SF.BVNDL39.450H17
SF.BVNDL35.250H10 *
SF.BVNDL3325.450H05
SF.BVNDL35.250S13
SF.BVNDL39.450H22
SF.BVNDL3325.450S11

copy these values to C: / ReStackor / Work_Dir / clkdat.in

SF.BVNDL35.250H10, needle taper
1.93
Nclk Dclk [mm]
1 1.73
24 1.279

<-- needle dimens for restackor

A = always 90°

Calculated needle taper height:
(compare to needle ht above)
(as if you stand there and measure it)
(adjust narrow needle dia to fit measured ht)

calcHt = 3

enteredHt = 3.0

B = calculated

C = needle taper

3.0

sinA

1.0000

sinB

.9986

sinC

.0523

a [as if no top needle dia]

16.73

b [ht as if no top needle dia]

16.71

c [1/2 of bott needle dia]

0.875

needle travel per click

0.1875

new ht b
[for calc below]

16.71

new bott needle dia
[for calc below]

1.75


needle and seat flow area, easily compared to other forks

clicks	needle travel [mm]	dia of needle at this point	flow area [mm^2]	equivilant bleed hole dia
0	0	0	0	0
1	0.188	1.73	0.57	( 0.85 )
2	0.375	1.711	0.63	( 0.9 )
3	0.563	1.691	0.68	( 0.93 )
4	0.75	1.671	0.73	( 0.96 )
5	0.938	1.652	0.78	( 1 )
6	1.125	1.632	0.83	( 1.03 )
7	1.313	1.613	0.88	( 1.06 )
8	1.5	1.593	0.93	( 1.09 )
9	1.688	1.573	0.98	( 1.12 )
10	1.875	1.554	1.03	( 1.15 )
11	2.063	1.534	1.08	( 1.17 )
12	2.25	1.514	1.13	( 1.2 )
13	2.438	1.495	1.17	( 1.22 )
14	2.625	1.475	1.22	( 1.25 )
15	2.813	1.455	1.26	( 1.27 )
16	3	1.436	1.31	( 1.29 )
17	3.188	1.416	1.35	( 1.31 )
18	3.375	1.397	1.39	( 1.33 )
19	3.563	1.377	1.44	( 1.35 )
20	3.75	1.357	1.48	( 1.37 )
21	3.938	1.338	1.52	( 1.39 )
22	4.125	1.318	1.56	( 1.41 )
23	4.313	1.298	1.6	( 1.43 )
24	4.5	1.279	1.64	( 1.45 )
25	4.688	1.259	1.68	( 1.46 )
26	4.875	1.239	1.72	( 1.48 )
27	5.063	1.22	1.76	( 1.5 )
28	5.25	1.2	1.79	( 1.51 )
29	5.438	1.181	1.83	( 1.53 )
30	5.625	1.161	1.87	( 1.54 )
31	5.813	1.141	1.9	( 1.56 )
32	6	1.122	1.94	( 1.57 )
33	6.188	1.102	1.97	( 1.58 )
34	6.375	1.082	2.01	( 1.6 )
35	6.563	1.063	2.04	( 1.61 )
36	6.75	1.043	2.07	( 1.62 )