Ball Bearing/s

nolacus

nolacus

New member
Location
Coventry UK
Hi,
Cleaning up the cases I removed the gear selector cover on my SF2 and the next case in that covers the chain.
There's a ball bearing as in the photo below but I think I read somewhere there are two?
Is this correct and if so where is the other one as no sign of it.

IMG_1082.JPEG
 
Thomas aus LAU said:
Correct!
You, better your motor ;) has there two balls:
clutch -> clutch rod inside gearbox gear 750 112.5mm -> Ball between clutch thrust rod Ø 6.5mm-> clutch rod inside gearbox gear 750 112.5mm -> Ball on clutch thrust rod Ø 8mm (that one at your picture)

See: parts for clutch

Thomas aus LAU
Click to expand...
thanks Thomas,
so the one in my picture is the furthest away from the centre of the engine, i can see the rod it comes up against and the other is further into the engine so as i've only taken off the two covers not visible, and i havent lost one.
 
nolacus said:
thanks Thomas,
so the one in my picture is the furthest away from the centre of the engine, i can see the rod it comes up against and the other is further into the engine so as i've only taken off the two covers not visible, and i havent lost one.
Click to expand...
If the ball is missing between the two push rods, you should notice this at the latest after assembly.
In this case, the path of the pressure lever is insufficient to open the clutch.

But you can also check whether the ball is still in the output shaft:
Take a short, thin hose with the maximum diameter of the push rod. Put some grease on the end of the hose and insert it into the hole until you feel a resistance. Then you generate a negative pressure on the outside of the open end of the hose ((syringe, suction pump, brake bleeder, ..., if necessary with your mouth) and pull the hose out of the hole.
Actually, this and, if necessary, the inner push rod always comes out of the shaft.

The push rods must be very straight (roll on a flat table) and the ends should not have any large indentations where the ball rests.
Of course, the balls also have to be round and free of defects.

Thomas aus LAU
 
piranha-bro2 said:
I thought they were both 1/4 inch? I'll be assembling one soon so will know soon enough.
Click to expand...
At the point of contact between the ball and the rod, a small indentation is inevitably created over time.
Since the rods partially rotate when pressure is applied, a ball that is too small can lead to a pulsating coupling or a coupling that is difficult to dose.
Trust the engineering skills of the Laverda technicians and use the two prescribed ball sizes!
You can get these at the nearest ball bearing dealer for a few cents.

Thomas aus LAU
 
Thomas aus LAU said:
Correct!
You, better your motor ;) has there two balls:
clutch -> clutch rod inside gearbox gear 750 112.5mm -> Ball between clutch thrust rod Ø 6.5mm-> clutch rod inside gearbox gear 750 112.5mm -> Ball on clutch thrust rod Ø 8mm (that one at your picture)

See: parts for clutch

Thomas aus LAU
Click to expand...
Thomas, use 1/4" balls (6.35mm) for the middle ball, 6.5mm is getting close to the actual size of the internal bore
I had reason to measure the internal bore of the mainshaft a few years ago at a depth of 93mm when I was vilified by a certain Laverda dealer and the mainshaft bore measures as follows over a series of mainshafts
6.618mm, 6.613mm, 6.605mm, 6.598mm, 6.582mm, 6.662mm, 6.675mm, 6.608mm, 6.595mm, 6.602mm

What you measure at the end of the shaft with a pair of verniers is not what the actual internal bore size is
 
I reckon I've only ever replaced the one between the rods, which is why I assumed they might be the same size - but I was correct in assuming 1/4" was the go.
 
Here is the exact information: Rex 50

The "clutch" which consisted of a disk with two 8 mm holes and a second disk with two 8 mm bolts was very primitive. So when starting up, you first had to pedal until the speed was right and the bolts could slide into the holes. But it was much faster than the allowed 25 km/h, perfect when you are 14 or 15 years old!

04114143545.jpg
Thomas aus LAU
 
You must log in or register to reply here.
Back
Top