X30 125cc RL - TaG

MAIN BEARINGS REPLACEMENT:FROM BALL BEARINGS TO NEW ROLLER BEARINGS

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MAN - 096 - EN

MAIN BEARINGSREPLACEMENT OF THE BALL BEARINGS WITH NEW ROLLER BEARINGS
It is now possible to replace the current 6206 ball bearings with the special roller bearings
BC1-3342B (p.n. X30125397).
Due to its characteristics
this type of bearing has
anextremely
longlifetime, also extending
thelifetimeofthecrankcase
asit
dramatically reduces thenumber of main bearing
replacements.
It also eliminates wear ofthe crankshaft journals
and helps to preserve thecrankshaft alignment during engine operation.
As shown on the pictures, the inner ring and the washer are not retained, and have to beinstalled onto the crankshaft as described by the following guidelines. On the contrary, therollers and the plastic cage are installed firmly into the outer ring, and must not bedisassembled.

For engine disassembling remove in sequence:
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The clutch-cover
The Bendix plastic cover
The clutch drum, then the clutch hub together with the starter ring
The Bendix
The ignition rotor and stator
The starter motor’s supplementary support on the left side
The starter-motor
The gears cover
The spacer and the balancer shaft driving gear on the crankshaft
The Seeger ring and the driven gear on the balancer shaft
The reed block cover, the reed block and the gaskets
The cylinder head, the cylinder, and the base gasket
The circlips, piston pin and piston
Open the crankcase and remove the crankshaft
Remove the balancer shaft
Remove the oil seals
Remove the main bearings carefully with a punch through the oil seal hole, heat thebearing seat area on the crankcase with a heat gun.
Remove the eventual shims between crankcase and bearings
Check the status of the bearing seats in the crankcase
1•••Clean the crankcase accurately
Prepare a clean horizontal plane as a base.
Take the 2 bearings from the boxes, separate the outer rings with rollers from the innerrings and spacers, don’t mix the parts between the two bearings.

ASSEMBLE THE NEW ROLLER BEARINGSASSEMBLING PROCEDURE
Assemble the new roller bearings by heating the crankcase (recommended).
• Degrease the outer rings’ external diameter and lay them on the base having the marking“SKF” visible.
• Don’t install the shims previously removed, normally they are not necessary.
• Protect your hands with heat-resistant gloves.
• With a hot air gun heat one half-crankcase by directing the air flow inside the bearing seatarea, with circular movement, until you get a temperature of approximately 100°C, so thatthe bearing seat expands to allow the manual insertion of the outer ring.
• Put the crankcase half horizontally on the work area, take the bearing with your fingers by
the interior, on the rollers, using a heat resistant glove. Put it straight into the seat until theend.
• Be sure the bearing reaches the bottom of the seat without bouncing back.
• Double check that the marking on the outer ring is visible.
• Don’t move the half crankcase until it has cooled sufficiently.
• Repeat the operation with the other half.
• It’s best to provide air cooling of the two crankcases by a fan, while they lay horizontally on
the work area to accelerate the cooling. Don’t cool them by fresh water.

2CRANKSHAFT
The inner rings have to be assembled onto the crankshaft journals and retained by aninterference fit.
It is extremely important to detect IF the used crankshaft is suitable to host the bearing’s innerrings.
If the result of the checking is negative, or in case of any doubts, a brand new crankshaft must
be considered. An insufficient interference will cause the release of the inner rings during
engine operation with a complete crankshaft failure as a consequence.
Take the used crankshaft, clean and degrease.
Disassembling the crankshaft itself is not strictly necessary, to perform the following operations,although it is suggestable for handling ease.
Now we proceed measuring the journals’ diameter, as the tolerance on journals is really strict,the measurement has to be carried out only with a fresh and good quality micrometer for
shafts:• measuring range 25-50mm;• resolution 0.01mm or less;• micrometer tips d.5-6mm;• The micrometer must be provided with its own zero-gauge.
Without the appropriate instrument, please don’t
perform the checking and proceed only with abrand-new crankshaft

The crankshaft and the micrometer have to be at
the same ambient temperature.
Very Important: proceed to correctly set the zeroon the micrometer, using its own zero-gauge.

Check the journals diameter at approximately
the center of journal length.
Verify that the measured diameter is between
Ø29.99mm and Ø29.98mm.
If the diameter is bigger than Ø29.99mm or
smaller than Ø29.98mm proceed with a brandnew crankshaft.
3Place the crankshaft onto the press plane.
If you are proceeding with an individual crankshaft half, please place the spacer p.n.10106
under the crankpin side to have a proper support on the base.
If you ae proceeding with the complete crankshaft, please insert the plate for crankshaft
disassembling (p.n.10104) between the two halves, and place everything on the support(p.n.10100). Again, use the spacer (p.n.10106) for proper support.
Installing the parts, we recommend matching the components of each single bearing.
Installthebearing
spacer. The side with themarking must face down
toward the crankshaft
body.

Place the inner ring onto
thecrankshaft,themarking and the bigger
chamfermust
face
upwards and remain
visible.

Press the inner ringusing a tubular punchwiththefollowing
dimensions:Øint.30.5mm
Øext.37mm or higher
L=100mm or higher.
Please note that theload needed for thisoperation is reasonably
low and even a manual
rack press is sufficient.
The tube-punch helps to press the inner hole parallel to the crankshaft axis.

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The inner ring is fully in seat when the spacer is pinched by the inner ring itself, and it can’t berotated by hands.
Repeat the operation on the other side of the crankshaft.
Before installing the new oil seals onto the crankcase, install the crankshaft, then close thecrankcase and tighten properly all the screws with cross-path at 8-10Nm.
Check the axial end-play, using the appropriate support provided with a dial gauge having
resolution of 0.01mm.
The end-play must be 0.35-0.5mm.
If the reading is higher, open again the crankcase, extract the bearings and install shims toachieve the correct clearance. The shims should be equally divided between right and left,
especially if the total thickness to be added is more than 0.1mm.
While checking the end play, just verify the presence of an even small radial clearance, whichis normally 0.01mm or higher.
Once the end-play is correct, open again the crankcase and remove the crankshaft, install theoil seals and add grease between the main and secondary lips of each seal.
Clean the sealing faces of both crankcase halves with diluent and apply sealing paste(“Motorsil” or equivalent) on one half-crankcase.
Don’t contaminate the sealing faces or the sealing paste with lubricant.
Install the balancer shaft.
Install the crankshaft, close the crankcase and tighten properly all the screws with cross-path at10Nm.
Placing the crankcase in the normal working position, with an oilcan lubricate the main
bearings by adding adequate oil quantity to the relevant lubrication holes in the transfers.
In the same way lubricate the conrod big end, on both left and right sides.
Make some crankshaft revolutions in order to spread the oil adequately.

REASSEMBLE THE COMPONENTSENGINE RE-ASSEMBLING - INSTALL IN SEQUENCE••
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The piston and piston pin, using brand new circlips preferably.
The base gasket, the cylinder, the cylinder head.
The reed block gasket, the reed block and the cover.
The driven gear and its Seeger ring onto the balancer shaft (markings for timing).
The driving gear and the spacer onto the crankshaft (markings for correct timing).
The gears cover
The starter motor and its supplementary support on the left side of the engine
The ignition rotor, having verified the presence of the key in the groove.
The ignition stator.
The Bendix, lubricating the two pins with viscous grease.
The clutch hub together with the starter ring, then the clutch drum lubricating slightly theroller cage spreading a small quantity of viscous grease.
The Bendix plastic cover.
The clutch cover.

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SPECIFIC INFORMATION ONROLLER BEARINGSREPLACEMENT
In order to allow the bearings to work with the appropriate
clearance and with the correct coupling between rollers andrings, please replace the bearings complete: outer rings withrollers together with inner rings and spacers.
To push out the bearings from the crankcase, an appropriate
punch (IAME ATT-075/2) is recommended as the load isapplied to the rollers.
The punch must be Ø39.9mm, with a pin Ø37.3mm to keepthe rollers in seat during the operation. See in figure.

To remove the inner ring from the crankshaft, use the specific puller (IAME ATT-048X).
The lip grabbing the spacer is necessarily thin, be careful to fit it exactly on the crankshaft.
Tighten the 2 Allen screws M8x30, then tighten the M12 screw (Hex.19) until the complete
extraction of the inner ring, blocking the puller body.

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