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J Range and Cento drive case noise.

I stopped riding the J50 in 2014, to try and solve a few sounds coming from the drive case.

The guy I purchased the J50 Deluxe from, gave me an extra set of Cento gears,
to make the J50 go faster.

About the same time, I purchased a crusty 1964 100cc Lambretta Cento motor.

My 1970 J50 Deluxe motor case was identical to the 1964 Cento motor case.

The Cento motor was untouched. That’s a plus, when finding original parts, and their setups!
Note! The smaller third gears to the right are the same.

With the Cento gears and the 100cc cylinder. The scooter was a great deal faster. 46mph!
But the motor would make noise coming from the side case area,
when the motor was fully heated up.

I took the motor apart one more time, and was thinking that the third gears inter spacing
looked to big. The gears came from the untouched Cento motor, they should be correct?

Here’s what I think. The third gear might have been redesigned with a wider inter space.
Some of the motor noise was coming from this area!

The inter gear spacing should always be, a bit smaller on the first gear, that’s put onto the
Layshaft. Here’s how it should look!

This inter gear spacing, might have been redesigned bigger, for the 100 and 125cc
extra power. The wider spacing makes it easier for the (Sleeve/Gear Selector Sliding Dog)
to find the gear slot.

I couldn’t find the Cento small slot third gear, anywhere. Then I found
Scooter Restorations.com
I emailed them a picture of the type of gear I was looking for.

The guys in England, worked with me through emails and found me the
correct third gear for a 1964 Cento motor. Very cool!

The smaller slotted gear worked great, and eliminated some of the motor noise,
with no problems shifting. I also put more oil in the drive case, that helped as well.

The J Range and Cento motor will always be noisy, because the gears are loose fitting
on a small diameter drive shaft. The number one noise maker? Very loose drive chain
and a bad design chain guide. It is, what it is. Vintage Lambretta fun.

3 speed J Range and Cento motor case noise, Solved!
Anthony Armstrong 2015

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