Modern Vespa

I have a 2-port 166 kit from ASC. I finally looked at all the parts and was a little surprised to see that the wrist pin circlips were cheesy-looking pieces of wire rather than "real" circlips that require snap-ring pliers. Would you use these or ditch them and go get some other ones? Anyone know offhand the size?

I think a lot of kits are going that way. My DR kit had those new wire spring clips, and mine popped out with only 200 miles on it. Not sure if it was the clip's fault or mine, just saying.

Those "cheesy-looking pieces of wire" are infinitely better than any "real" circlip, use them!

The groove that accepts the wire clip is rounded in profile instead of square as needed for the old style clips. Don't try and use other clips than what the piston was designed for, bad things will happen.

The wire clips are much lighter than the old style and are able to stay put at much higher engine speeds. They may look wimpy but once you get past that they are a dream to work with.

Aha! Good call, I hadn't even thought about profile of the groove. Totally makes sense using a round wire clip if the groove is round. Makes me wonder if this is the reason we hear about wrist pin circlips "failing."

the only down side to the wire clip it it can sometimes be hard to see when they have seated.

I always inspect them with a magnifying glass to make sure they are sitting in the groove. Some times they will end up too far in and you can use the wrist pin to move them out a bit till they seat.

Hello

If you look at the snap ring, if they are stamped out of sheet they only go in one way.
Wrong way and they can come unseated.

Grumpy

The wire G style ones are fine. But for the love of Jesus dont reuse them

The "cheesy" looking clips are very old school and the were very common in pistons for a zillion years. They're easier to remove and install too.

You used to run in to soft metal plugs once in a while, made lead I guess, you fit one to each end of the wrist pin which was free to float and they harmlessly rubbed the cylinder a bit if the wrist pin drifted that way..... a bit weird but they worked!

Good information oppsclunkthud.

We've never had one come out ~ yet. *knock on wood Vespa"

HRA does it the same way, does not trust the cir-clips.

The wire clips are superior.

This is a very good bit to remember. Most people have never heard this.

The stamping process will round the edge of one side of the piece, while the other side is a sharp edge. You must have the sharp edge facing outwards, away from the piston.

OK...so what's the trick to getting the wire ones in. I have had fights with them and had them go shooting across the shop. Any tips?

Also I think I read somewhere that the opening should be towards the back...is this correct?

I use a pair of needle nose for the G clips. The C clips that come with the Malossi kits are the bane of my existence.

I'm one of those people who had never heard that. Learn something new every day!

Good info there, thanks.

grip the bend-in on the "G" with needlenose, set the other end into its seating groove in the piston, and push up and in with your needlenose pliers to seat the bent-in end of the G into its half of the groove. Bit hard to describe, but it works for me. After doing a bunch of cylinder kits in a period of 2 months I got pretty proficient at it. No problems with that G-wire style circlip that I know of on those motors.

My understanding is the opening in the G should be aligned with the front/back axis of the piston. This limits its compression of the circlip when the forces change the direction of piston motion from front to back and make it less likely to pop out.

The Gs don't look too bad...but like Travis said...I have a really hard time with the Malossi ones. They can take an eye out at 50 yards!