Jetting Query

[Zino]

down shifting is mainly the contra springs job
stiffer contra equal quicker down shifting

clutch springs 
is for take off 

variator weights is so you shift in the meat of the  power band 

[Zino]

Oct 25, 2023 10:27:04 GMT -5 dwint said:

That's the first thing i change when i start a build.Take off is day and night.I always use white contra with yellow clutch springs.I couldn't fix my bog awhile back and it ended up being a fouled plug from so many different tests.Make sure its plenty warm before any carb adjustments too.

Your take off might be that you put the polini clutch in with the stock unpainted spring these are soft springs just like stock .

Dwint is running yellow malossi that is a medium strength spring polini medium strength spring is green i run polini greens on my vinos i ran malossi yellows on the zuma with similar set ups to yours 

the white malossi contra is stiffer than a stock contra and works great with a sport level build .

Do you have a tach ?
Or a temp gauge ?

Both would help immensely dialing in your scoot 

[Zino]

here is a good blog that has your pipe and kit combo
www.pedparts.co.uk/blog/sports-exhaust-testing-50cc-and-70cc-sports-mopeds-part-two

[seacoastzuma]

I don’t have a temp gauge on it rn but I did a bit ago, and with similar jetting I think I saw peaks right around 300-308 ish, losts of 280-295 while riding. I do a ton riding in 25-35 mph (mostly 25) so it’s a lot of full acceleration and then stopping, so I’ve only really gotten to run the bike hard once to get it over 300. My lead on my temp gauge has broken since then and I’ve gotta replace it just haven’t yet. Do you have any tips to determine if my air screw and fuel screw setting are right? The bike seems to do a little better when it seems to be rich on idle, but I don’t want to use incorrect idle mix as a crutch. Even when hot, it never loads up or stalls at lights, and idles super consistently, so is that good enough?

[Zino]

For idle jet you need to be able to control the mixture from 1 to 3 turns out
Otherwise you need to go to a bigger jet if you are less than 1 turn out or go to smaller idle jet if you are more than 3 turns out

To dial in the idle mixture quickly

with scooter well warmed up .
Let it idle on the stand or at a stop sign .

Note rpm speed (if you have a tach this is easier)
Blip the throttle .
3 things will happen

If idle speed drops below regular idle speed and then cleans up and rises back to normal you are on the rich side for idle mixture you could adjust a notch leaner.
The rpms drop back to normal speed real quick
This is close to perfect
The rpms stay above normal for a little bit and hang there you are lean .

For the main jet i just take the jet that gives me the highest speed via gps at wide open throttle on at least a 1/2 mile run.
.
If 2 jets give similar top speed I take the richest one

For the needle take the position that is most responsive at 1/4 to 3/4 throttle.
If 2 feel similar i take the richer one .

After this I may need to move the idle mixture a 1/4  or so to clean up 0-1/4 throttle

This is the order I go
Set a functional idle
Set The main to a safe wide open jet
Then dial in the needle for responsiveness

[seacoastzuma]

Ok then I think my idle jet is pretty close then. When it’s 55-65 out I’m about 1-1.5 turns out of closed to get the best return to idle when warmed up. It now 25-40 degrees out and dry and I might size up on the pilot for the cold season. It’s gotta be the transmission then, right?

[Zino]

For tempature changes from 40 to 90 degrees
I dont ever change pilot jets after I get one that works within 1-3 turns out any adjustment can be handled by a 1/8 to 1/4 turn at most.
Your temps say you were rich enough for your riding style .
Street light to street light up and down throttle you can run tighter leaner jetting on the main.
If you run wide open for miles on end you need to run richer main jets .

I still think its the cvt

[anttikauko]

To clear out the carb issue, can you please list all settings on your carb:
pilot jet
needle type
atomiser size
main jet
slide cut