Nut

1
Big end brg
Oil hole
Seal A
Shim 0.037 thick
M24 x 1.5
Lathe center-drill feature
Pin
Flush
Clutch
Lock plate
Key, 5.0 mm wide
Nut
Pilot brg
Journal of web 2 (separate piece)
Do not remove from web 2
0.695
30 mm
Rod (Made in Japan
on both rods faces Dynastart end of crank -- but
it may not matter)
Crank stub of web 1
Pilot brg seal
Grease space
Seal A race
Bearing A
10.0 mm force fit
10.0 mm sliding fit
Oil guide
Seal lip spring
Web 1
Web 2
Piston pin brg


One piece
Exploded view of 1972 L50 Suzuki crankshaft.
Drawn by Bill Hutchison wchutc3_at_aol.com
502-897-2373
Ring Qty 2
NOT TO SCALE
? 1.920
10.0 mm Alignment holes
Seal B
Shim 0.037 thick
Groove
Serrations
Gap
Slide fit
Force fit
Pin
M10 x 1.50
Pin
Pin
C-clip
Center-drill
Center-drill
Rod and rod brgs not shown
No gap
Distributor drive gear
Journal of web 3 (separate piece)
Do not remove from web 3
30 mm
Crank stub of web 3 (separate piece)
Do not remove from web 3 -- believed to be shrunk
fit
0.0914 to 0.915 inches
C-clip ears
Bearing B
Brg C
Brg D
Seal D
Oil guide
Seal B race
Web 3
Web 4
Seal C
Oil hole
Seal C race
Flush
Exploded on next page
2
NOT TO SCALE
This piece goes in oil pump side of crankcase
Piston pin brg
Crescent retainer
One piece
C-clip groove
Groove for crescent retainer
Force fit
Pin
Rod
M10 x 1.50
Pin
Distributor drive gear
C-clip
35 mm
25 mm
Ears
Dynastart
Seal C race
Brg C
Brg D
Seal D
Web 4
Seal C
All bearing anti-rotate pins go in oil pump side
of crankcase.
Big end brg
Drawing notes 1. Some features like oil holes and
C-clip ears and the woodruff key are not shown
clocked in the correct angular position for
clarity. The clutch woodruff key position is not
alterable. The oil holes for the rod big ends
should be placed so that their open ends point
approximately 180 degrees away from the
crankshaft centerline (to obtain the best effect
from centrifugal force.) C-clip ears should point
either towards or away from the crankshaft
centerline to lessen the loosening effect of
centrifugal force (I do not know which position
is better for balancing). 2. The side of the
pilot bearing seal with the spring (that holds
tension on the seal lip) should be installed to
face the pilot bearing. 3. Pilot bearings have a
rounded end and a square end. The rounded end
should be installed into the bore in the web 1
crank stub as shown. 4. Seal races are shown the
same width as seals. In reality they are somewhat
wider than their mating seals. The seal races are
medium force fits and are installed hard against
whatever is adjacent to them. Therefore, there is
not enough clearance behind them, usually, to
engage a bearing splitter. In this case, for seal
race C, use a brass drift through a crankweb
balancing hole to dislodge the race enough to
engage a splitter or puller behind it. 5. Seal A
and C have the same basic dimensions (except that
seal C is 2 mm wider) and would apparently
interchange. However, seal A is made with much
more rubber than seal C (which is mostly formed
from sheet metal) and they have different Suzuki
part numbers. Perhaps seal C runs hotter than
seal A or maybe one of these seals has been
replaced. I do not know . 6. The large crankweb
balancing holes adjacent to the con rod journal
holes are not shown in the drawings for clarity.
See page 4 for pictures of the balancing holes.
3
Crankshaft disassembly Douse all joints with
penetrating oil before attempting to separate the
crankshaft. It may not be necessary but it cannot
hurt. 1. Remove seal D. Write down all numbers on
seal ____________________. Carefully measure
distance from dynastart-end of shaft to bearing
D. Use a dial caliper or depth micrometer. (Mine
measured 1.920 inches.) Write this dimension down
____________________. 2. Use a two or three arm
puller to remove Bearing D. If a bearing is to be
reused, it should never be pulled by its OD but
here I am assuming that the old bearings are to
all be replaced. Write down numbers on bearing D
____________________. 3. Remove C-clip adjacent
to bearing C. Note position of ears
____________________. 4. Bearing splitters come
in about three sizes. The middle size is perfect
for L50 crankshaft work. A medium-sized splitter
by K-D Tools (P/N 2264) is pictured on page 4.
Engage your splitter in the groove of bearing C
(or behind it, adjacent to seal C) and remove
bearing C with a two-arm puller. The splitter
should not be torqued together. In other words,
tighten the splitter so that it will not shift or
move during pulling but not so tight as to damage
anything. Write down numbers on bearing C
____________________. 5. Remove seal A. Write
down numbers on seal A ____________________. 6. En
gage the splitter between bearing A and the
adjacent oil guide. Only about 1/32 of the
splitter lips will engage behind bearing A.
Tighten the splitter with fingers only else the
oil guide will be bent. Carefully attach a
two-arm puller and make sure everything a square
for a straight pull. Use an electric impact
wrench to tighten the puller to avoid putting
stresses on the puller that might make it slip.
If the bearing does not seem to move after a few
turns of the puller screw, remove the impact
wrench and strike the head of the puller screw
with a steel hammer. This will loosen the joint.
Continue with the impact wrench. Bearing A should
pull off along with seal race A. Write down
numbers on bearing A ____________________.
7. Measure clearance between both big end
bearings and the adjacent wall of the crankweb.
(They should both be about 0.025 inches). Write
this information down. Clutch-end rod bearing
clearance ____________________. Dynastart-end rod
bearing clearance ____________________. 8. Either
end-most crank web removes the same way. Use a
small two-arm puller through the crankweb
balancing holes adjacent to the rod journals as
shown on page 4. This will be a tight fit for
most pullers. Position puller arms as shown on
page 4 where the claws of the puller arms point
away from each other. Pack the puller arms in the
balancing holes with stray bolts or whatever.
This will keep the arms from slipping off the
small ledge they have available. Put a nice
smooth socket between the puller screw and the
rod journal so that the journal bore in the crank
web will not be harmed. Note the socket will be
somewhat off center on the rod journal -- make
sure that it bears only on the rod journal. Use
the impact wrench and hammer if needed. I have
not observed any numbers on any rod bearings
(big-end or little-end). However, write down any
you may find. Clutch-end ______________
Dynastart-end _____________ Also write down the
width of the big-end bearings (new bearings may
measure different) Clutch-end ___________________
_ Dynastart-end ____________________.
When reassembling, this width plus
the clearance (step 7) must remain the same.
Increase or decrease the clearance to
compensate. 9. Repeat step 8 for other end-most
crankweb. 10. Carefully position a large two-arm
puller on web 2 and push out the crank stub of
web 3 along with web 3 itself. Use the impact
wrench and hammer technique as before. This joint
is a tighter fit than the others so use care and
be prepared for the impact wrench to do lots of
work. I cannot recommend a three-arm puller due
to the relief in the web for the con
rod. 11. Remove seal B. I have not seen any
numbers on seal B (except it is marked Ars or
Ays. I assume this is the manufacturer). Write
down any that you may find ____________________. 1
2. Repeat step 6 for seal race B and bearing B.
Write down all numbers on bearing B
____________________. Your crank is as apart as
it needs to be. 13. Go off to the bearing store
to shop for all the bearings and seals you
removed. See if they can provide oversize big-
and little-end bearings for the connecting rods,
if needed. 14. Thoroughly clean all nooks and
crannies where centrifugal force has packed in
crud for all these many years -- especially the
inside rim of the oil guides and all oil
passages. More later when I get replacement
parts and reassemble my crank!!!! I plan on
filling the crankweb balancing and alignment
holes with balsa wood for increased crankcase
compression -- an old two-stroke racing
trick. Note on seal race B The Internal Diameter
(ID) of seal B should show almost zero wear. The
rings are designed to rotate in the groove of
seal race B. Therefore, the rings remain
motionless with respect to seal B. If all
is well, seal B and seal race B should not need
replacement.
4
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5
Data Vehicle 1972 Suzuki LJ20VL Brute Body
number 108469 Engine L50 (359 cc nominal),
bored 0.5 mm over Engine number 192488 Odometer
23,763 miles Crankshaft Bearing anti-rotate
pins Roll-pins, 2.5 mm OD x 5 mm long (0.10 x
0.205 inches) Clutch nut 32 mm across flats,
10 mm thick (called a Low nut, referring to
thinness), M24 x 1.5 Pilot bearing seal No
markings. 10 mm ID x 15 mm OD x 5 mm (0.210
inches) wide. Seal can be somewhat wider if
needed. Pilot bearing Enclosed needle roller
bearing. Markings HKS 10x15x15 INA-NTN
Dimensions 10 mm ID x 15 mm OD x 15 mm
long Seal A race Medium force fit onto
shaft. Nominal dimensions 30 mm ID x 44 mm OD x
12.5 mm wide. Seal A Markings NOK
AH6864E 4.6 Dimensions 72 mm OD x 44 mm
ID x 8 mm thick. Flange 76 mm OD x 1 mm
thick. Bearing A Markings KOYO
83555-9 Dimensions 72 mm OD x 30 mm ID x 20
mm wide. Shoulder 65 mm OD x 3.7 mm deep. Oil
guide shims Both shims are the same.
Dimensions 43 mm OD x 30.5 mm ID x 0.037 inches
thick. Big-ends Bearings not marked.
Clearance twixt bearing and web 0.025 inches.
Width 0.695 inches. Big end journal 0.914 to
0.915 inches OD. Big-end
bore 1.272
inches. Little-ends Bearings not
marked. Width 0.932 inches. Piston-pin OD
0.627 to 0.628 inches. Little-end bore 0.788
inches Seal B race No markings. Dimensions
1.714 inches OD x 25 mm ID x 0.454 inches wide.
Groove width 0.118 inches Seal B race
rings 46 mm (1.811 inches) OD uncompressed,
1.651 inches ID uncompressed, ring thickness
(each) 0.057 inches, Gap when compressed in
seal
B about 0.010 inches. Seal B Markings
Ars or perhaps Ays. It is hard to read. No
other markings. Dimensions 72 mm OD x 44 mm ID
x 8 mm wide. Flange 76 mm OD
x 1 mm
thick. Bearing B Markings KOYO
83555-9 Dimensions 72 mm OD x 30 mm ID x 20
mm wide. Shoulder 65 mm OD x 3.7 mm deep. Seal
C race Medium force fit onto shaft. Nominal
dimensions 44 mm OD x 35 mm ID x 11.2 mm
wide. Seal C Markings NOK DC5Y44
72 6.7 8.7 1.5 Dimensions 72 mm OD x 44
mm ID x 10 mm thick. Flange 76 mm OD x 1 mm
thick. Bearing C Markings KOYO
83553-9R Dimensions 72 mm OD x 35 mm ID x 17
mm wide. Groove 0.070 inches deep x 0.080
inches wide x 0.123
inches from face of
bearing. Crescent retainer Dimensions 79 mm
OD x 69 mm ID x 0.070 inches thick, arc about
170 degrees C-clip Dimensions 32 mm ID,
0.057 inches thick Distributor drive gear Need
to define this, just in case. Bearing
D Markings HIC 83464 Dimensions
62 mm OD x 25 mm ID x 17 mm wide. Seal D (race is
crankshaft) Markings Ars or perhaps Ays
Japanese character (see page 7) SD-2552 10-R
B1 Dimensions 52 mm OD x 25 mm ID x 10 mm
wide.
Flange 55 mm OD x 1 mm thick.
History Vehicle has been in storage since 1981,
when I bought it. Vehicle smoked very badly when
I drove it home. At least one holed piston about
1980, both cylinders rebored to 0.5 mm oversize.
Crankshaft still littered with debris, all
bearings feel very gritty. Front-most seal
directly behind dynastart leaking very badly,
perhaps too much grease in distributor gear area
is cause. End-most seal directly behind clutch
also leaking but not as badly. Despite abuse,
most journals and surfaces and cylinders show no
wear or scoring. One rod big-end however, does
have a large pitted area.
Always measure your own parts. These dimensions
may be different than yours.
6
Exploded views of all crankshaft parts except
piston pin bearings. All parts are laid out in
order, as in drawings.
7
Pilot bearing seal. No markings. Metal side faces
clutch.
Pilot bearing by INA-NTN or HKS(?) End shown
faces clutch.
Seals A and C have the same overall dimensions (
However, seal C i2 2 mm thicker) yet construction
is totally different. Perhaps one of these has
been replaced but Suzuki has a different part
number for each seal. Seal C race is narrower
than seal A race.
Seal A by NOK
Seal C by NOK
Bearing A by KOYO
Seal B marking Ays or Ars ?
Bearing C by KOYO.
Bearing D by HIC.
Seal D. Marked with Suzuki S. Manufacturer Ays
or Ars. The race for this seal is the web 4 crank
stub. Note that shaft rotation is indicated.
Would the seal really only work for this
rotation? Or is it just to make sure that the
seal gets installed the right way around?
Seal B race. Note tapered portion of ID.
Bearing B by KOYO.
8
Sheet metal oil guide.
0.146
2.5 mm
0.138
65 mm
Special bearing features could perhaps be ground
to size on standard bearings. Bearings are very
hard and the anti-rotate pin hole cannot be
drilled. Perhaps EDM?
Homemade dynastart puller. Bolt thread is M12 x
1.25 pitch. Torque the bolt in place fairly
tight. Then tap head of bolt with a steel hammer.
BE READY TO CATCH THE ARMATURE. SOMETIMES THEY
LITERALLY JUMP OFF THE SHAFT!!!!
Bearings A and B
Crescent retainer for bearing C is not quite a
full semicircle. Anything somewhat less than 180
degrees should work.
I hope this guide might help someone -- the crank
was not as hard to separate as I thought it would
be. Please notify me of any mistakes
wchutc3_at_aol.com 502-897-2373 I am interested in
buying any Suzuki LJ parts and cars. From basket
cases to full restorations. Interested in LJs
only except also first model SJ. Especially want
any optional parts like gas-fired interior
heaters. Also interested in any original LJ
literature. Also looking for Subaru 360 parts
and cars. Please contact me about any technical
know-how rebuilding two-stroke crankshafts.
Coming up next (hopefully) Standard Replacement
Parts, Putting it All Back Together and, Aligning
the Crank