Modern Vespa

Don't know the law... but if you push fast then you both overcome inertia and get momentum on your side.

And it's been a while since physics... but the thing with springs is they resist with constant force. The spring constant =k

not constant force, but proportional to the length of displacement. F=K*d

And 2x4's don't drink all your beer, either.

I realize I may be the last person on the forum still using a castellated clutch nut. But if there are any others out there, do yourself a favor and BEVEL THE EDGE of the nut removal tool.

The tool works OK with the engine out, but I spent a whole frustrating afternoon trying to get the teeth to to grip the nut with the engine in the scoot. There's basically no way to put enough leverage on it. It just slips off.

Beveling the edge of tool lets it sits deeper in the teeth. The nut'll twist right off. Then throw it away and get a shouldered nut.

The tool barely fits into the six spring clutch on my sprint, so I'm feeling kind've dumb I didn't think of this myself. In general, I only use the damn tool to remove castle nuts, but I haven't have flange nut that will fit in there yet and I forgot to see what SIP had when I ordered my new axle & cruciform last night.

Yep, I still use them and I jumped on this when I saw it here:

Been out of this vespa thing for a bit, so I'm picking up new things these day in the past I have always used the castle nut, and personally never had any issues. Although I know others do. I always used a new nut + cage when removing/replacing.

I understand the advantage of using a shouldered nut for ease of using a standard socket, and I would think more even distribution of force. What about locking it down without the cage? Split-ring or toothed lock washer is sufficient? Same factory torque specs as the castle nut?

[quote="GeekLion"] This type of nut is supposedly single-use. I read that the threads, compared to a normal nut, is very slightly different. That means that they deform just a little, enough to grip the male thread. I have re-used them however and never had one come loose from the clutch over the last 10 years.

I dug through by tool box of Vespa specific tools today to find my custom made socket. I didn't have the correct socket at the time, so I made one. I think I made it sometime around the turn of the century? I also found a couple of the correct sockets as well. I must have had the same issue as everyone else, because apparently I sanded down a taper on it so that it would fit. I guess that should tell you the last time I've used one of those castellated nuts!

Me too, about 10 years ago the first time I needed one and I didn't want to wait a week for the special tool. I had an extra clutch nut and discovered that it fit perfectly with the other one so I welded a short fat bolt on it and pulled the clutch shortly after. Works well if you are in a jam, but the steel is not hardened and it won't last like the real deal.

Ginch: Thanks for that info and link. I have one of these nuts I got from SIP/DRT a while back but never used, #11351940. Scootermercato sells what appears to be the same one... both retail approx $10. SIP has another option without the washer for 1/3 the price.... I'm sure there are others out there
I wonder if these are actually true "Jet Nuts" as they come with a toothed lock washer. Or are they simply machined "flange nuts" with NO self locking characteristics...


Some more detailed information about the Jet/K nut and how it achieves the self locking through Eliptical offset on part of the threads., As you said Ginch!

Jet-Nut / K-Nut - from wiki
A jet nut,[1] also known as a k-nut,[1][2][3] is a special type of hex locknut that is commonly used in the aerospace and automotive racing industries.[3]
It has a flange on one end of the nut, the hex is smaller than a standard sized hex nut, and it is shorter than a standard hex nut. It achieves its locking action by using an elliptical offset on the un-flanged end of the nut.[4]

Elliptical offset nuts
Elliptical offset nuts is a catch-all category that encompasses designs known as oval locknuts[1] or non-slotted hex locknuts,.[3] The salient feature is that the threadform has been deformed at one end so that the threads are no longer perfectly circular. The deformed end is usually shaped into an ellipse or obround triangle. These are known as one-way nuts as the nut may be easily started on the male fastener from the bottom non-deformed portion, but are practically impossible to start from the deformed end. As the male fastener reaches the deformed section it stretches the threads of the nut elastically back into a circle. This action increases the friction between the nut and the fastener greatly and creates the locking action. Due to the elastic nature of the deformation the nuts can be reused indefinitely.

Reusing Locking Nuts
The FAA has issued guidelines on the reuse of locking nuts. Specific recommendations have been published for larger sizes (7/16-20 and up), but the general rule is that you should not be able to turn the nut by hand once the locking portion engages the male threads. If you can turn the nut with your fingers, it must be replaced. When in doubt, replace!


On a slightly different note: digging into thread locking/bolt lossening on Boltscience.com. Interesting stuff for a Geek if you want to dive in deep! Basicly they say that split-ring washers do NOT help secure a nut, and actually cause it to fail sooner than just a plain nut alone. This is only preliminary research. Not thinking specifically for the clutch, just general purpose info for those who want to dig deeper. I think I shall

Just found this on a smallframe group on fb. Great idea - use shrink wrap to hold the top hats on the cable outers!

AND - colored shrink wrap around cables & wires to match the paint color!!

Superglue works just as well... when installing

or just put them on the inner before feeding it in.

On the other hand, the bit around the two shift cables is a good idea. my GS still has the two shifters crimped together with a metal band.

...and if you look closer, it appears that there's a solid round metal rod (3/16"-1/4" diameter) welded into the legshields?

Not willing to part with my hard earned cash to replace, cut and re-code the key. I decided to bend up a paper clip to act as a loop and then use heat shrink to secure it to the actual key.
It has worked a treat. Cost me nothing as I already had the items laying around the house.
Even if you want to get a new key cut, this little hack should save you from losing your key while waiting for the replacement.
Happy scootering🛵

I just ran across this in a video about restoring a T-55 tank. Removing a frozen bolt that's sheared off.

https://youtu.be/nVBX3YX50M4?t=417

If you don't speak Dutch, just click the CC icon to turn on captions

By request: How to get the dustshield off undamages to use again, so you can remove the damn muguard and again, the photo details so you can weld up an edgeformer tool of your own.

a linoleum knife is gonna make it so much easier
also an old paring knifr, a small hammer and a couple of thin strong prying tools

Use the paring knife first to get a small gap
working around it wth light hammer taps being sure you are getting into the gap

Once you have a gap the linoleum knife can use same tap tap all around but harder taps and the linoleum knife fits the curve nice to make it easy

now pry up gently and evenly, it's the bearing that's tite
dust shield is loose now

all done and the dust shield is still good to go

Edge tool: clamp TIGHT and 'roll' the metal to reshape frame edges and looser over a rag or piece of leather to work aluminum trim.


I like a curved longer upper piece to use for a little easier going around corners which is 'challenging'

just clamp it together to weld obviously

no hard and fast rules on sizes, radius the inside end edges on the lower die

Great idea on the edge tool.

I realized when I went to put everything back together that I'd lost the small steel plug in the clutch cable pinch bolt. A quick trip to the hardware store and I came back with a nail and a #3 tinners rivet. I was worried the rivet would be too soft and a quick squeeze in the vise showed that the rivet mushroomed too much to easily fit into the pinch bolt, but its a good comparison to the thickness of nail you need. 60 seconds of work with a dremel and a cutoff disc and I made a small steel plug that fit right into the pinch bolt and I was able to put everything together. Not an amazing hack, but it beats waiting for a new part to ship to you.

Thats a good useful tip. Much better than leaving it out and jamming that bolt into the cable as some do who dont realize the plug is even there.

I just never take the bolt out of the top so the plug never can fall out...

^^^ Maybe if it's new, but I ALWAYS take it out to verify the plug is there coz half the time it's not and I have to find another or do what Hal did.

and some aftermarket ones never had the plug, so removing it identifies those.

I pull the bolt out most of the way and then shake it and look through the hole to see it is there, then turn it upside down and shove the cable through.

I had a hard time finding a clicking noise in a motor. I wasnt sure if it was the cush drive teeth or a gear with a bad tooth.

With the cases split and clutch removed, I hooked a drill up to the castellated rear axle nut, removed the circlip and gear shim and spun the gear cluster slowly, pushing in on the gears with my free hand. Heard the noise so I removed first gear. Spun and heard the noise, removed 2nd gear. Spun and the noise went away. Reinstalled 2nd gear and spun, noise is back.

Switched cush drives and repeated the steps. Noise still on 2nd gear. Replaced second gear and everything was happy.

So, moral of the story is get a drill and spin the internals to help troubleshoot gear meshing problems

great tip!

were you able to identify the bad tooth? bent?

Yep. Once I found the bad gear, I adjusted the drill rpm and with enough time I was able to narrow down the problem area within an inch. Then I found the bad tooth and the damage was as clear as day.

Wow, its so satisfying when you actually identify the root of the problem. Good work!

Nice one MJ!

and before catastrophic failure, well done!

Hello There.
First the hint. The Crankshart thread pitch is "Metric Fine" (I can't recall if it's an 8 mm or 10mm Dia but I do know it's 1.50 mm Pitch. most nuts you will find are. X by 1.75 mm pitch.

Tip No:2
Working on the electrickery?

Get a set fo coloured Pencils (Or nick your children's crayons for an hour.

Pick a Circuit. Choose one Wire at a time and draw it on a piece of paper.
When you now go looking for the fault, you can wade though the spiders web looking for the pink or blue etc wire and can happily ignore the rest.

Needed to renew the numbers on my shifter and didn't want to mess with painting and wiping off the excess. Found an oil based Sharpie paint pen at a craft store. It has a very fine point that tracks inside the numbers.
Just clean out all of the old gunk with a scratch awl. A couple coats and you are done.





Last edited by exmayor on Thu, 06 Feb 2020 12:44:23 +0000; edited 1 time

There is also a good selection of lacquer based colors of pens in the nail polish section of your local drug store.
Some with pretty fine tips too.
(Some pretty fine tips in this topic too! )

For those who have little space, small wallets and/or like to build stuff More here: Scooter stand

some of his pics:

The ingenuity built into that scooter stand is very interesting. Am I the only one who feels nervous looking at the photos? Seems like it could be very precarious getting the scooter pushed up, and tilting the table without dropping it off the side....