Shift issue (SS180)

[Kent]

I have a 1966 Vespa Supersport that has a shift issue: Shifts are not positive and it tends to slip out of the chosen gear (occasionally). When it does this it is only one gear but that gear is not alaways the same depending on cable adjustment. Is this a cruciform or selector box issue>

Any advise would be appreciated.





Thanks.


Kent

[joe]

if your selector cables are properly tightened, and still slips out of gear, then I'd say it's the cruciform.

worn cruciforms are common. you'll need to drop the motor, split the cases, swap out the cruciform, replace seals and gaskets. you can do it in a day.

[spiderwebb]

could it be the selector box itself...??



http://www.scootermercato.com/Garage/Te ... ox-Rebuild
"inspect the teeth for any wear
this can be a cause of your bike slipping out of gear if the teeth are badly worn."

and how about the condition of the plunger...??
I remember years ago I had one that was worn to a nub and loose = shifting was sloppy not matter the cable adjustment. With the cover off mine I could see its age and how loose it way.

if your lucky it is just the selector box

[Miguel]

My vote is for cruciform, it takes a lot of shifting to wear out a selector box.

[Tuna Cowboy]

Probably the cruciform but do check the selecter arm play, there is.a pin that holds it in and can get warn. Do you know the last time the cruciform was replaced? How many miles since a rebuild?

[Kent]

I dont know, I doubt that either have been done (since new). The bike was hit while parked and I am going through everything that has bugged me. I ride it hard (peak dynamic range) and ive worked everything out but this. The front drum is a bit out of round so I plan to turn it so that the front brakes are useable. I will send photos of the shifter box. Its a really clean stock restoration. You guys helped me when I was finishing it up in 2010.

When replacing the cruciform I need:

Crucifiorm

Seal

Gasket set

?

[joe]

When replacing the cruciform I need:

Crucifiorm

Seal

Gasket set

?

sounds about right. you might inspect the bearings while you're in there too

[joe]

speaking of SS180s, here's a project we did a few years ago. I think it's time for another!

https://www.flickr.com/photos/topdeadce ... 915257228/

[lookn4bikes]

My 63 GS160 does the same thing. I rebuilt and replaced the selector box numerous times. Spent a ton of time adjusting shifts cables. It does a little better if I shift with no or minimal clutch. My vote is cruciform. But I figure if I split the case may as well do a rebuild or refurb. Not much fun to ride with the random ghost gear.

[spiderwebb]

cruciform needs to be replaced and / or loose gears lugs checked for wear
you can do this without doing a full rebuild
I would check clutch and top end while it is apart

do make sure the plunger selector is not loose where it attaches to the selector box finger and that it is not worn down and thin causing looseness

[lookn4bikes]

In my case it was the cruciform. Original 3k motor. Hated to split cases but I tried the easy stuff first. It was very clean inside but cruciform was worn. Hopefully my problems are solved.

[Miguel]

That is definitely a worn cruciform that needed to be replaced

[spiderwebb]

Keep the old used parts for art projects....