Modern Vespa

I recently replaced the gearbox after several of the teeth were sheared from the primary gear. Got everything back together and vespa runs fine.

Now, however, I am having some trouble with shifting through the gears. The gear selector rod will move easily through the gears while turning the rear wheel by hand and the selector box will move with minimal effort when not mounted. When mated and the selector box is mounted to the engine casing, though, it is very hard to move through the gears with either the selector cables or by hand.

Any ideas?

I read your post correctly and I read it twice because I needed to visualize it in my head. so basically everything moves freely by hand as long as is not fully mounted and tightened correct? that makes me think that perhaps the cables might have some play on the barrel adjusters. Typically the selector works good even without grease, it is a spring loaded mechanism with detents(teeth). have you give it some grease? how is the clutch cable? is it properly tightened.

I think that if you minimize the clutch cable and gear cable play things will "click" better. when you were undoing the selector box did you remove the two 11mm nuts and pulled out the whole selector with cables or did you loosen the shifting cables too?

Thanks for the response! Side note: I am in Tucson as well.

I removed both the 11mm nuts and the shifting cables while working inside the case. Yes, I have greased the selector box, and added some between the selector box and the selector rod.

I cracked open the "head" behind the headlight and think that you might be onto something with the shifting cables. They seem deformed around the shifter barrel and the "slack" around the barrel seems to be what is making the shifting hard.

I have ordered new cables and new nipples for the selector box and will report back after they're installed.

^^ Nice to hear that you are in Tucson. The headset barrels can be a nightmare, sometimes we lean these scooters on the lefts side with the shifter pushing the floor and sometimes the cables get stretched and kinked.

Even if you are not opening the cases the scooter benefits greatly from tigheting the cables once in a while at the selector box. I personally use gorilla tape or I have someone holding the shifter for me on the neutral position and I tighten the cables so eliminate the slack. If you over do it you can also have the effect of having hardtime shifting.

If you are in Tucson the fastest way to get parts is Scooter-speed in Azuza California or scooterwest in San Diego, both shops ships lighting fast to Tucson and for about the same price. If you are serious about keeping the scooter you should get the whole complete cable kit, it is a life saver. In what part of town are you? I am on Valencia near the Casino del Sol area.

Great-- thanks for the recommendation on the shops. I'm sure that I will use them going forward for future orders.

The parts should get in tomorrow and I'll report back if this fixes the issue!

I'm in midtown, around El Con.

It's easy to get slack in the headset. I always end up pulling them tight a couple times before they are right.

And this is when you're riding the scooter, or just when the scooter is not running while standing still in your garage?

Thanks, All, for the responses!

It was difficult to shift through the gears while riding, pushing the scoot with the engine off, or while shifting and turning the wheel by hand.

I received the new cables yesterday and those seem to have fixed the issue! It is much easier to shift now and actually operable while riding.

I understand that I'll have to tighten the cables to accommodate stretching after installation. Any idea how long to wait before doing that? I set the cables with the head unit dissembled while installing a brighter LED headlight (picture) and the position dot is just a tad off center. If I'll need to retighten them soon anyway, I'll just wait until then to actually center on the dot.

Thanks again for the help!

The cables will let you know when they need adjusting, one day it'll just be hard to shift again. Tighten them up with the barrel adjuster and they'll be good for a longer while after that.

They stretch pretty quickly. If I remember correctly. Less than a hundred miles.

Glad you got it sorted. Shift cable installation and adjustment can be a real hassle.

The best technique I have found to do this job was pioneered by VOODOO, and makes the job quick and easy; especially if working alone. There are pictures on here somewhere, but here is my best explanation:

1. Install the cables from top down, and get them seated properly in the shift cable pulley in headset.

2. Thread cables into the selector box, and loosely install the cable barrel clamps into position, but do not tighten.

3. Install a second set of cable clamps at the very ends of the cables, and tighten.

4. Clamp a Vise-Grip clamp onto each of the extra cable clamps.
*#3 can be skipped, and the vise-grips can be clamped directly to the cable.

5. Hook a bungie cord to each Vise-Grip, then stretch each bungie and attach the other end to some point rearward of the scooter. This will put tension on both cables, while still allowing adjustment of the handlebar selector.

6. Adjust the handlebar selector to align the dots.

7. Tighten both of the cable clamps in the selector box. Make sure to push each inward, so they are seated properly in the cam.

8. Undo bungies, vise-grips, and extra cable barrel clamps; then make any necessary fine adjustments with the threaded adjusters.

Enjoy smooth confident shifting!

Thank you both!

It's running and shifting great at the moment, but I'll use this guide in about a 100 miles or so, or when it starts to shift a bit differently.

Sincerely appreciate the help, all! It feels great to be back on the scoot (even with the 105F heat )