Modern Vespa

I have been searching the forum for the answers and I'm not coming up with what I need.
So, I reach out to the tech guru's of the Inter-webs.

My scoot is a 1981 Vespa P200E. It has a 24/24 carb with:
-Idle Jet: 55/160
Main Jet Stack:
-Air Jet: 160
-Mixer Tube: BE3
-Main Jet: 116

I want to install the Chrome SIP Road 2. The up jet I was thinking is a Main 122-124.

Does this sound right to you?
What else should I change?

Thank you

Robin

Pictures for the fun of it.

Normally you up jet 2-4 point. The chrome version may need more because it's lack some baffling stuff in the box. Beware, those exhausts are pretty loud and tinny sounding compared to the painted version.

PureDrivenSnow,
The tinny sound is what I'm looking for.

So, if this model originally came with a 20/20 back in 1981 and now is a 24/24, would this change the equation for up jetting?

Also compounded, Since the Chrome does not have sound attenuation, would this also affect the jetting equation again?

Robin

Run a 122 if youre at sea level. The rest of your 24/24 jetting is spot on. The only reason I'd say run a higher main jet would be if you have the heart in your air filter drilled OR if you run wide open freeway runs all the time.

Don't worry about the 20/20 carb. Those were installed to meet emission requirements, not engine requirements.

I have a 1983 p200 in a 68 sprint....I have the exact same jetting as you, but I run a 122 main in the winter, 125 main in the summer. Summers here can be in the 100's for many days in a row. I tend to run a bit on the rich side....just to be safe. As MJ said 122 main. You should be right in the ballpark.

Excellent feedback guys.
So what is the difference between the Dellorto 122 and the SIP 122?

Well if your talking about jets I'm not sure there is a difference. I have some of each.

If you look at them under a magnifying glass you'll see the tips of the nozzles are machined a little differently. BGM jets are different still. I haven't compared the actual tolerances. Haven't noticed any difference in the way they perform.

exactly the post was looking for

about to buy a carb with

air;160
main;116
mixer; BE3
idle;55/160

already have a 122 main so should be perfect as I have a sip road 2

PS
don't see any red on the scoot, I wonder how many times it would be booted over if you parked it at Parkhead. I painted the hubs red on mine to finish off the theme white walls, a bit more subtle, but living in Glasgow...