Furry oilmagnet, Knackered SKF 6305C3 bearing

[kejj]

This is after 990km since a complete rebuild and 780km since last oil change.
Still furry. I'd better check. Having also some issues choosing first gear when bike is cold.





In iron Lambretta cylinders we trust!

[rosscla]

Would bet that the clutch top plate is rubbing on the kickstart

[kejj]

Rosscla! You won the guessing game. Clutch shim was 2.3mm and IT pushed the clutch out towards the kick start. The top clutch steel had marks in it and the kickstart base too.



In iron Lambretta cylinders we trust!

[kejj]

I understand alignment was made to the front sprocket and thus required a larger shim. Still this large shim should have triggered off an alarm.

While looking at the front sprocket I found this movement. Don't remember it to be this flex in my other rebuilds. Crank bearings gone wrong.
https://youtu.be/ZmXCrzxdxCY

In iron Lambretta cylinders we trust!

[kejj]

After disassembly of the front sprocket set up I found that the crank moved towards all angles. Up and down, left and right and in and out.
My guess is that the metall that was grinded off from the top clutch steel and kickstart shaft found its way and destroyed the bearing.

Either that or the SKF 6305 C3 bearing made in India have reached a new low in quality since it means it only lasted 1000km. I've had SIL bearings last longer.

Next up is to disassembly everything and check the condition on the crank itself, the flywheel side bearing, oil seal and any other parts that might have been affected.

When It comes to bearings, I have always preferred SKF, as mentioned the last ones I bought were made in INDIA, I was a little suprised by this but trusted the QA process within a well known company.

I have the same bearing in another engine. Will have to keep a close eye on it. Have also assembled engines with FAG bearings.
Next I'd try the Koyo out. the seem to be praised by some engine builders.

[Lambretta Sash]

Just goes to show what metal can do in a chaincase, you probably screwed the bearing with the ginding paste you made.
Its not unusual to use a large shim, however the endplate can only fit where it does unleashed you have a spacer under it,
Personally i uswest skf bit of European manufacture
Is that the correct kick start shaft to suit chain case?

[warts]

Have you checked the gear box too?

SKF bearing are made in India to proper specs - if they are genuine they are as good as any.
The fault is yours for running an incorrectly assembled engine.

[shocky]

I understand alignment was made to the front sprocket and thus required a larger shim. Still this large shim should have triggered off an alarm.

While looking at the front sprocket I found this movement. Don't remember it to be this flex in my other rebuilds. Crank bearings gone wrong.
https://youtu.be/ZmXCrzxdxCY

In iron Lambretta cylinders we trust!

I always set the rear as low as it will go with the thinnest shim I then lap the front drive sprocket sleeve down to suit yes its time consuming but so is a strip down

[kejj]

The bearing could have given away at an earlier stage and thus using the chain to push the clutch towards the crankshaft.
The oil throw washer shouldn't have allowed any gearbox oil passing through.
The kickstart is the same that left Innocenti factory 1965! This bike had only had one previous owner. I didn't rebuild the chain case myself though.
The gearbox is still clean and clear, no marks to the parts in there. One stud is unwinding itself when I try to torque it up.
Next time I'll try to lap the drive sprocket sleeve. It is an original innocent item so I didn't want to mess with it. The rear sprocket is a lightened race type from Casa.

Next up is to get the crank out and see how it looks and hos the mag housing bearing have fared!

[kejj]

I've disassembled everything. The SKF bearing definitely had it. It's only fit for the bin now. The oil seal survived although and didn't let oil through. The crank seems OK visually inspected. The oil seals on the mag housing had it and began to let oil and grease through into the crank area. Guess the nu2205 bearing is going need to be changed as well.
I'll post pictures later in the parts removed.


In iron Lambretta cylinders we trust!