this guide in full
Screw type Puller. Read these instructions carefully before starting.
screw type pullers MUST be used with great
care and MUST NOT simply be screwed in when attempting to pull a
gear or split the engine cases. You tighten the puller screw then hit
the head of the screw with a heavy hammer. Tighten a quarter or half
turn and hammer again. Repeat until the screw simply won’t tighten
further – never try to force it or something will be damaged. It is the
impact from the hammer blow that “pops” the 2 items.
primary drive gear can be the most difficult of any carried out on a
JAWA CZ engine and you should follow these instructions carefully or
risk damage to the crankshaft and the removal tool. Consult your manual
and a qualified motorcycle engineer if in doubt. Wear safety glasses as
metals splinters may fly off the tool or the gear.
primary drive chain – it does not need to be split. By removing the bush
in the centre of the clutch drum there is sufficient slack in the chain
to remove it from the drive teeth. Reassembly is the same in reverse.
Fit the chain and then insert the clutch sleeve. The primary gear
sprocket is a simple taper fit on the crankshaft. There is no keyway or
any splines. A taper can produce one of the strongest bonds and can
prove difficult or even impossible to break. Worst case scenario you
must split the sprocket using an angle grinder - making sure you do not
damage the shaft.
Heat on the
gear might help but releasing fluid is a waste of time as it cannot run
into the taper fit due to the close tolerances.
retaining nut for the gear. Ensure the nut on the end of the crankshaft
is flush with the end of the shaft. That ensures that when you try the
process the shaft end is unlikely to be damaged. Take great care.
special puller on to the collar on the gear and gently wind in the
centre bolt ensuring the “pull” will be directly along the line of the
shaft. When finger tight use a spanner to take out all slack and then:
Tighten the centre bolt by one quarter turn.
not try to simply wind up the centre bolt of
the puller or you will break the puller or damage the end of the
Hit the head
of the centre bolt with the heaviest hammer you have. The gear may
simply pop off. If not turn the puller centre bolt ¼ turn tighter and
whack it very hard again. The idea is that the impact jars the gear
free of the taper.
is to keep tightening the puller centre bolt by ¼ turn between each
whack. You will know when you are getting to the limit as the centre
bolt will become increasingly hard to turn the extra ¼.
If you get to 1 and ½ turns and the gear
remains in place consider heating the sprocket with a blowlamp or gas
welding torch and whacking it again. There is no exact science – one
member once said you need a thumpometer! Just bash the head of the
puller bolt as hard as you can.
the crankcases and finding there is no movement you have almost
certainly missed one of the holding screws
JAWA CZ Owners Club
accepts no liability arising from providing this advice.
If you do not accept
this do not use these tools.
By Pete Edwards
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