Fuel petcock

MICHAEL FRENCH /

So I finally got to messing with my vespa grande. And before I even start to replace the chain tires or fixing a fuel leak (why it hasn't moved in years) I discovered the fuel petcock doesn't flow at all. Is the petcock packing something treatland stocks or am I going to have to rig some other valve up?

One more question in ran and bought a bicycle chain and it doesn't fit. If I start it about about 10 or 12 links it's on top of the sprocket instead of meshed with it, what chain do I need to buy?

Re: Fuel petcock

if your talking about that rubber washer w three holes, I havn't seen them, if its not too bad sometimes you can flip it, but it much easier to buy a new one and a new chain while your at it. the chain for multi speed bikes is smaller, it don't fit.

Re: Fuel petcock

MICHAEL FRENCH /

Well I thought about flipping it, but it only has one hole and a large half ring molded into it from the valve. I'm pretty sure it's dead but I'll go give flipping it a shot and see if I can stop it from leaking. I dont know if that's why but it had about a pint of gas that had an interesting smell to it and was thick as hell. Guessing the oil.

Also this bike had a fuel tube to see the level, my dad who bought it new said it was a dealer installed option, can anyone confirm If this was an option or accessory? I ask cause if it's an option I'll put it back on if it's an accessory it might be removed in an effort for simplicity to get it back on the road

Re: Fuel petcock

petcock rubbers have three holes(atleast). much easier to just purchase, as far as the mysterious tube, post a pict and someone can identify.

Re: Fuel petcock

Could be the filter. I pulled mine out today. I had to use a dental pick because broke inside. The filter was all yammered up like it was too long for a Grande tube tank. Shoulda took a pic.

Re: Fuel petcock

MICHAEL FRENCH /

HOLY HELL. so I flipped the packing, it's good now, and tried to start it. No dice so I removed the carb. The carb inside everything was full of what looked like silt. I'm a dummy and didn't take pictures. Cleaned the carb 3 times but it still wont idle, I'm hoping that will be just the idle "jet" because I don't remember seeing it 🤞🏻

Re: Fuel petcock

> MICHAEL FRENCH Wrote:

> -------------------------------------------------------

> HOLY HELL. so I flipped the packing, it's good now, and tried to start

> it. No dice so I removed the carb. The carb inside everything was full

> of what looked like silt. I'm a dummy and didn't take pictures.

> Cleaned the carb 3 times but it still wont idle, I'm hoping that will be

> just the idle "jet" because I don't remember seeing it 🤞🏻

You don’t have an idle jet, per se. But there is an idle passage hole that you need to clean out. It’s a tiny hole under the slide, behind the intake shim. The hole leads into the emulsion tube, allowing a tiny bit of gas to be sucked thru the throat at idle. Here’s a pic. Just poke a small wire thru the hole, then blast clear with compressed air.

D1938EA6-0148-4519-A05B-2D1198FB6AE3.jpeg

Re: Fuel petcock

MICHAEL FRENCH /

I knew there isn't an actual jet in there but looking online people were referring to it as a jet 🤷🏼‍♂️

In this picture you can see the tube I was referring to used like a site glass for fuel level

Cant figure out how to attach a picture(edited)

Re: Fuel petcock

I'd like to see that glass site.

Re: Fuel petcock

MICHAEL FRENCH /

Picture was to big 🤦🏼‍♂️

Tank is almost empty so I doubt you can see where it's at here. The zip ties were put on by my grandpa when I was a kid and almost ripped it off(edited)

20200522_143127.jpg

Re: Fuel petcock

that add on tube is cool but is not stock. The inframe vespa grande has an air bleed under the seak to allow gas to creep up the rear section of the frame.

Most people overlook the idle jet/passage. Although u can not unscrew the jet and change it "out", u can definetly clean it, u can drill it thereby enlargen it or u can fu by not lining up the emulsion tub. The jet along with your throttle slide meters your low end idle richness. oddly it is much bigger thain yout main, around a 72 or so.

Re: Fuel petcock

MICHAEL FRENCH /

That tube isn't a vent it's just a fuel gauge. I know my dad bought it new with it on there I just didnt know if it was a vespa thing or dealer installed. Its hooked to the fuel line after the petcock.

Thank you guys for the help.

One more question, battery this time, the battery was removed when I was a kid, I looked it up it looks like it's a b39-6 but I'm having trouble finding one, might. Be covid or do they just not make that battery anymore. If they dont make it does anyone know a battery size that fits right in these?

Re: Fuel petcock

> MICHAEL FRENCH Wrote:

> -------------------------------------------------------

> battery size that fits

> right in these?

Just measure the battery box and find the biggest 6 volt with the highest AH that fits .

Re: Fuel petcock

> P D Wrote:

> -------------------------------------------------------

> > MICHAEL FRENCH Wrote:

>

> > -------------------------------------------------------

>

> > battery size that fits

>

> > right in these?

>

> Just measure the battery box and find the biggest 6 volt with the

> highest AH that fits .

Go to a farm supply store, and get a 6 volt electric fence battery. They are sealed batteries, and they work great. Super cheap too! Get the highest mah batt you can fit.

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