Modern Vespa

I am rebuilding a 1967 2-Port Vespa GT Engine (VNL2T). It has the leaf type spring, not the later PX style coil spring, to engage the kickstart gear. I replaced the kickstart gear, but not the spring or quadrant. When I reasslembled the engine, but the kickstart gear clicked against the adjacent gear when I turned the cush drive. I took the cases apart to see if I can tell what's causing this and it appears that the quadrant just doesn't push the kickstart gear far enough when it returns to the natural position. The kickstart gear is behind the wedge of the quadrant, but the wedge doesn't move it far enough to clear the adjacent gear. Has anyone run into this and is there a solution? I appreciate the help!

If the spring is good it should push the gear into the recess in the quadrant. Weak spring ? It is replaceable. When parked, there is very little disengagement clearance.
Maybe the quadrant is not returning fully to its parked position for some reason and the drive gear is against part of the ramp on the quadrant ?
Could it be that the lay shaft is not fully seated in the bearing and is sightly farther out than it should be ?

I really don't know why it isn't returning. Maybe not the right quadrant gear combination. The spring seems too strong. It's pushing it all the way out past the quadrant so it's always engaged. I'll check to see if the lay shaft is seated, but I am pretty sure it is. It's already torqued and there's very little clearance on the rivets on the back of the cush drive.

Click goes the kickstart gear.

Sorry I got that sort of jumbled up. Seems to me that if the quadrant is located properly, the only way the gear could be interfering is if the lay cluster is not.
Also... can't hear the click : no audio..

There are more than a few different kickstart cogs. All very similar looking. Are you really sure that's the correct one?

Measure the diameter on the primary...

The shaft is 21.75mm. The inside dimeter of the kickstart gear measures at about 21.85mm.

I don't know that I have the right gear or quadrant. I am kinda winging it and i dont what was done or changed to this engine prior to takingnownership of it. The gear is 12/12 teeth like the adjacent gear. Everything seems to be right to me, it just doesn't work as designed. It seems like the narrow edge of the wedge on the quadrant needs to be thicker by about 2-3 mm.

I can't upload a mp4 so I made a GIF to upload for the visual. I can take more video or pictures if needed.

Thanks for the help!

This distance is 2.63mm.

Did you install both rubber buffers in the case? Could the kickstart quadrant be in the wrong place/ wrong part?

The rubber buffers are in and the quadrant seems to be fully seated in place. The quadrant is the same that came in the engine. I replaced the kickstart gear.

Do you still have the old gear? Same
Tooth count? Same height?

I don't have the old gear, but lined them up when I get the new one and the teeth are the same. I didn't measure the height. Do they come in difference heights?

I have this one
https://www.scootermercato.com/Scooter-Parts/Kickstart-Gears/89229

FWIW... the SM listing states not fitting any before '62. You show yours as being '61 ( before the GL was produced).

Maybe you need this one ? : https://www.scootermercato.com/Scooter-Parts/Kickstart-Gears/58680
I don't know the difference.

What does the Motor # tell you ?

The body VIN number comes up as a 1962 GL... I corrected that. The engine number comes up as a 1967 Vespa 125 GT Motor.

Tom

Yup. SM listing shows it fits VNL.
I sure hope you can figure this one out.

Did you ever end up figuring this out? I am having the exact same problem.

Thanks.

I did! I bought a new kickstart quandrant and replaced the old one. The problem went away.

The old and new parts were slightly different. On the old part, where the wedge is that returns the kickstart gear, the thickness of the front edge of that wedge was only about 1/16". On the new part, that "knife edge" at the wedge is was more like a light 3/16". In effect, the new part pushes the gear back an extra 1/8" compared to the old one.

The new one was part# 140920 From Scooter Mercato. My engine is a 1967 GT 125.

Hope this helps.

Tom

Thanks! That may very well be my issue. It's a new quadrant but I think the wedge part might be machined incorrectly. It's a crappy looking part.

Do you mean this?

This distance I highlighted in red is what was very different on my two quadrants. The thicker the end of the wedge, the more the gear is pushed back out of the way... with all other things being equal.

Thank you!

Excellent photo editing by the way!