Maybe useful info, not really all that comprehensive yet

Oil filter

Brandpart numberwhere to get it/notes
OEM15410—MM9—013
suberceded by
15410—MFJ—D01
~ $12 list, ~$8.50 mail order
Identical to the Kawasaki OEM filter for the EX500, both made by Toyo Roki.
About $9.  The following three are the same, all made by WIX, supposed to be better than OEM
NAPA13582-¾" long
WIX51358
Carquest85358
About $6.  The following three are the same, all made by WIX, this is a "car" filter, about 3.5" long
NAPA13563-½" long
WIX51356
Carquest85356
HiFlow314-0303about ¼" longer than stock.
EMGO10-82230 (black)Highly recomended by the list
EMGO10-82220 (chrome)
Mobil-1M1-108 or M1-110about $12.  The difference is filter length, both should work
Bosch3300 grade Acan be found at autozone for about $5
Bosch3323 grade Acan be found at autozone for about $5, about 3.5" long
K&NKN-303about $12, comes with a nut drilled for safety wire on the end, 3-3/8" long overall
PurolatorML16817
perf-form#J-503perf-form.com
FRAMPH6017A / 314-6017Some people have very strong feelings about never using Fram filters ever, others say the problem has been corrected or that it was only a very small run that had the problem.
AC DelcoPF2135
MotorcraftFL-816about ¼" longer than stock, but fits fine, about $4

Don't forget the 14mm crush washer for the drain plug!

More info on filters can be found here

If you want cross references that others have used for other applications:

Oil Drain Washer

The little aluminum washer that goes between the drain plug and oil pan is 14mm
You can use a copper one too.
the OEM part number is:
WASHER (14MM) 	  94109-14000

Honda recomended spark plug

Don't forget you need 4 of them.
NGKND
Standard DPR8EA-9 X24EPR-U9
For cold climate
(below 5° C/41° F)
DPR7EA-9 X22EPR-U9
For extended high speed
riding
DPR9EA-9 X27EPR-U9
Gap 0.80-0.90 mm
(0.031 - 0.035 in)

Fuel filter

OEM16900-MG8-0e3
EMGO1115-006for Goldwing, fits GL1500/6
JC Whitney#120561About $2.29 plus shipping
Purolator car filter with glass body with a removable exchangable element

Battery

brandmodel #comments
YuasaYTX9-BS
EverStart ES9BS from Waltmart, about $50
same battery as 93-98 CBR 900RR, 87-00 CBR 600-F/2/3/4, CB-1, Suz. Bandit-400 and lots of others.
More on batteries here.

Bulbs

Locationbulb type
Front turn signal bulbs#1157 or 2057 or 1034 or 2357 or P21/5W 12v, 32/3 cp, 23/8 watts
high brightness Honda alternative: 34906-SL0-A01 (43/3 cp)
Rear turn signal bulbs#1156 or 2056 or 1073 12v, 32 cp, 23 watts
Brake/running lights bulbs#1157 or 2057 or 1034 12v, 32/3 cp, 23/8 watts
Headlight bulbH4/9003/HB2 60/55 watt high/low beam
Spedometer illumination light#194
Tach illumination, oil pressure, neutral, turn signal, and high beam indicators Honda only bulbs as far as I can tell.  more info here: www.hawkworks.net/manual/hints/bulbs.html

Tire sizes

FrontRear
110/80-17150/70-17stock
110/70-17160/60-17Very popular alternative

Stock chain and sprockets

525 O-ring, 112 links, 16 teeth front, 44 teeth rear

Replacement levers

part #DescriptionMSRP<-- nobody ever pays this
14-0211Motion Pro clutch lever$10?
14-0217Motion Pro VFR brake lever$21This fits nicely, and is adjustable
53170-MW0-006OEM 90-97 VFR brake lever$22
30-52021Emgo FVR750F 90-97 brake leverSame EMGO part for F2/F3 and a few other bikes, but different Honda part. Verify!
30-52051Emgo 53170-MY9-861 adustableYuk! Wrong shape, doesn't feel right

That really big nut that holds the rear axle together

46mm or 11316" (they're the same size)
The imperial/English version is cheaper and available at the FLAPS (Friendly Local Auto Parts Store.)

Rear wheel mounting nut

27mm

The size of the torx bolts that hold the ignition in

T-40

Tapered head bearing info

Top bearingBottom bearingnote
Timken part number This bearing looks like a Timken 32005, and in fact some aftermarket replacements say that on them, but it isn't.  It's a modified one with a 26mm I.D., rather than the 25mm of a 32005. 

Nachi (and others) make a 32005 with a 26mm ID. Their part number is E32005JS/26. Search for “32005/26” or “32005-26” for many options.
32006 This part number is a generic metric bearing number, and any bearing shop should either have it or be able to get it quickly.  I quote Timken because the local shop said it was the best bearing manufacturer out there.  Even if he's just spouting, they're still a good brand and this price is much cheaper than the part from Honda.
O.D.47 mm55 mmThis data is probably useless, the part numbers above should describe a unique bearing.
I.D.26 mm30 mm
height (measured)15.6 mm17.9 mm

These don't include the dust seals.  Stock dust seals cost about about $4 and $8.30 for the top and bottom respectively if you buy them on-line.

There are tapered head bearing kits available that include both dust seals. That's probably the path of least resistence.

brand part number notes
All Balls 22-1020
Parts Plus SSH-903R
Slinky Glide AH-3577 wemoto part number

Honda used the same combination of bearings and dust seals for something like 80 models over 40 years.
Here is a cross reference.

Front wheel bearing

The left and right wheel bearings are identical.
NSK part number6004(v)The "v" is the seal type.  There are several types.  "v" is the non-contact type, which will last longer, but not be completely waterproof.  The contact type (I don't rememeber the suffux) is more waterproof initially, but doesn't last as long.
You should be able to get these bearings at any bearing shop.
I.D.20 mm
O.D.42 mm
height12 mm
Priceabout $12 each.

Front brake rotor

Mike Dean says, "... a stock VFR Rotor from the early 90's should be the same part, other than a style difference."

The Hawk's front brake rotor is 316mm in diameter

EBC's fitment chart suggests that the following rotors are usable: I have not checked this! -Webmaster

Braking part numbers:
Wave: HO26FLD
Smooth: HO26FL

EBC part numbers:
MD-1021LS or MD-1021RS

Brake pads:

Brand:BrakingDPEBCSBS
(Parts Unlim.)
TuffstopVesrah
front- SDP117HH FA142HH 1722-0031 TSRP-827 VD-156
rear 711SM15 DP115 FA140HH - - VD-147

What's intereseting is that EBC lists the FA226HH for the front of the CBR600 F3,
but all the other vendors say the F3 and hawk use the same front pads.  If it were
me, I'd get the FA142HH pads if they were available, the FA226HH if that's what's
in stock.

Brake hose:

Front
Length81 cm / 32 in
Top banjo20° bend
Bottom banjo20° bend
Rear
Length (not measured yet)
Front banjo
Rear banjo

Brake rebuild kit part numbers

WhereWhatWhoPart NumberParts Unlimited #Dennis Kirk
Frontmaster cylinderHonda45530-471-831
K&L32-1078191741
Moose RacingMD06-00106-001M194009
K&S54-10011702-04301914109
caliper sealsHonda45109-166-006 & 45209-166-006
K&L32-1163
K&S19-10011702-01611907918
caliper pistonHonda45107-ML7-691
K&L-
Moose Racing-
Rearmaster cylinderHonda43520-MJ6-305
K&L
caliper sealsHonda43209-371-006 & 45109-443-870
K&L
caliper pistonHonda43107-KT7-761
K&L

OEM style air filter

OEM17210-MN8-000
EMGO12-90480

UNI pod part number and info

Part number for 4" UNI pod air filter:

part number:UP4229
I.D. 2-1/4 in / 57 mm
Length4 in / 102 mm
Their web site:unifilter.com/online-catalog/clamp-on-air-filters/

The 5" is identical, but for length, and the part number is UP5229

Mirror thread

10 x 1.25mm (fine thread)

Paint codes

1988 NT650 Hawk GT

Colorite paint codes

Honda color nameHonda color codeColorite skurequires baseNotes
Candy Flair BluePB115C20641050’88 only The sales brocure calls it “Tanzanite Blue”
Tempest Gray MetallicNH119M2030None’88 only (Honda code NH152?)
Italian RedR1572228“Factory Variance Color”, ’88
Italian RedR1572228-1“Factory Variance Color” ’89-’91
Granite Blue MetallicPB184M2072Canada color, looks black.   77220-MN8-671ZA

The Honda colors sometimes have a "U" at the end. e.g.: NH119MU

Replacement (cheap) thermostat

Stant 180° part number 35788 or BT 378 180

.:Hawkeye:. sez:

Cheap replacement radiator cap

Napa small radiator cap part number 703-2443
interchangable with 703-1443 (both 13 lbs)

Radiator Cap Relief Pressure:
   88 - 127 kPa (0.9 - 1.3 kg/cm2, 13 - 18 psi)

Fork Seals

41 x 54 x 11 (I.D. x O.D. x height, in mm)
same size as CBR600F/2/3

OEM51490-MM8-305includes dust seal, one side only
SKFKitG-41s (green)Better than OEM, kit includes dust seals (KitB-41s is black) 2024 SKF fitment guide
K&L15-5087OEM spec or better, pair, no dust seals
K&L15-5441OEM spec or better, pair, includes dust seals
K&L15-2567OEM spec or better, rebuild kit including seals, wipers, & bushings
K&S16-1041Seals only
Leak ProofDO NOT BUY!They suck.  They leak, like within days.

Cheap ass fork seal driver

You can use a schedule-40 PVC coupling for 1-1/4" PVC pipe as a fork seal driver.  They can be had at Home Despot for about $0.45, the only modification you have to do is to grind/file the ridge in the middle away.  Cheap and easy.

Cartridge emulators

Mfr.part no.notes
RaceTechFEGV S4101The orginal
YSSPD335post patent expiration copy for 25% less

Racetech Emulator install specs:

OEM compression
damping holes
Drill out to 5/16" (8mm),
Total compression
holes
six total.  Three through holes.  Holes must be 90° offset.
vertical spacing of holes⅜" (10mm) center to center.
Emulator spring64lb/in (yellow)
preload2.0 turns4.0 for smooth road-racing tracks.
More than 2 on the street is harsh.
oil weightUS-2 / 33 cSt @ 40°CMany like heavier, ~45 cSt
oil height165mmReduce this by 2.65mm /cm of spacer if
you use PVC instead of aluminum.

Fork Springs

34.7mm OD

Mfr.series no.notes
RaceTechFRSP S3534###### is rate in kg/mm
Traxxion DynamicsOMNI.#### is rate in kg/mm (confirm fitment before buying)
not clear how spring diameter is specified
Progressive Suspension11-1126these are progressive rate, not straight rate
It's the same spring for the Hawk and a Goldwing

Fuel quick-disconnect

Male and Female Shutoff Valve, Part No. 245-1495 from: Lockhart Phillips, $21.50 each

You need the 5/16" valve for the Hawk.  Female shutoff (#245-1493, $16.95) works fine for me.  BTW, these valves may be found at most good bike shops.

“Quick Connector for 5/16" Tube”, p/n 217025, $11.33

You can also find it if you root around in the McMaster-Carr catalog (well worth having around; also at www.mcmaster.com).

Rear stand info

Diameter: 28.5mm (Pit Bull)

Same as VFR750/800 and CB1000R

Pit Bull pin: H

Also work:
KTM 1290 Super Duke
Triumph Daytona T595/955 (a little long, a little loose, but works fine)

Front stand info

tripleclamp pin type stand pin diameter: 24 mm
Pit-Bull stand pin: Std pin + #1 adapter

Soichiro Honda's birthday

November 17th 1906

Japanese industrialist Soichiro Honda, born in Iwata-Gun, Japan (1906).  He ran several small manufacturing operations before and during World War II.  After the war, he had great success manufacturing a small gasoline engine that could be attached to a bicycle to transform it into a motorcycle.  He began the Honda Motor Company, producing first motorcycles and then small sports cars.

More at Wikipedia

Ok, so this one isn't that useful, but it's kind of cool.