Yamaha vino 50cc 2t exhaust

[luke0000]

I recently got this Yamaha vino started, it caps out at about 50km per hr. I have heard of people boring out their exhaust for more speed. (I have already removed the restricter washer). It looks like the exhaust from the engine side is restricted.(not sure how to add image) I was expecting for the restriction on the actual exhaust pipe but here is what mine looks like. The question is can I bore that hole out? Or are there any restrictions or things I can do to improve speed?

Thanks in advance

[Zino]

vinos are great little scoots I have built a pair of them up
that pipe wont let the engine rev out much past 8k rpms

the restriction is in the head end of the pipe the part that bolts up to the cylineer
it has a restriction that makes it only a dime sized hole .
There is a spot weld that you dremel out and then it is a quarter sized hole
This will make it flow better

You probably will need to go up on the main jet to keep from cooking your cylinder
I ran the mikuni jets in the 70 to 75 range with my vinos
jetsrus.com/a_jet_kit_scooter/yamaha_50_vino.htm

Make sure that you get a new exhaust gasket when you put the pipe back on
I always use permatex sealant to get a good seal
Air leaks are deadly

To make sure you are sealed up tight on the exhaust
You can test it
Take a wet rag with the scooter running and plug the end of the exhaust if it kills quick you are good if it keeps running you have a leak

[Zino]

this is where the restriction is and how to dremel it out
not exactly the same pipe but you will get the idea
www.pedparts.co.uk/blog/yasuni-exhausts-how-to-derestrict

[luke0000]

I believe the previous owner had removed the restricter. You are saying to upgrade the jet on the carb?

It’s about -3 c where I live and now that it got colder the only way that the scooter will start is if I put my finger on the intake until it starts. I’ve looked at a few other posts, it could be the enricher?

The bike will only get to around 50kmph

And how could an exhaust leak be deadly (genuinely curious I don’t know much about these scoots)

Thanks for the help!

[Zino]

with 2 strokes like this a proper fuel mixture/air mixture provides 80% of the cooling .
So on these 2 stroke scooters you need to run carbs on the rich side so that you keep from over heating your engine causing it to seize up .

If you have an exhaust leak it would cause your mixture to have to much air not enough fuel and so it would run hotter than it should and could push you closer to engine failure .

[luke0000]

I can say that there is no exhaust leak as you said to check I covered the exhaust while it was running with a wet cloth and it died almost instantly.

I have been reading different things, the rollers could be flattened?

Also many people say that the scooter should do 45mph with all restrictions out. So I’m really curious what the issue would be

[Zino]

I derestricted my vinos in the trans and exhaust pipe and was still under 40 mph
The stock variator is designed even derestricted to not get all the way to the top gear
So I swapped on a malossi variator and had better take off and top end
The stock exhaust also holds you back it doesn’t reb past 8 k rpm’s when you de restrict it gives better take off but it still has a ceiling on top end

A better pipe makes a big difference
I pushed past 45 mph with a higher gear ratio through the better variator and higher rpm’s with a better pipe

Then I went over 50 by upgrading the cylinder to a 70 cc malossi

[Zino]

a few vino guys on here to follow their builds
gutiwarrior ,tiny, ziptiejones, crankingwithcg, bigmathew86, oldgeek

[luke0000]

So the first things I should upgrade is the exhaust, and variator? If I were to upgrade them would I have to change something else along with those.

Also you mentioned rev limiter, would changing the cdi to a performance make it rev higher as I’ve seen people say that it restricts the rpm.

I really appreciate all the info 🙏

[Zino]

There is no rev limiter on the cdi on the vino
The stock cdi will keep up all the way to 11000 rpms

The rpms are limited by the stock pipe and the ports of the cylinder .

Every pipe has a power band this is where it makes the most power
The stock pipe power band starts at real low rpms and cuts out at about 8000 rpms .

[Zino]

If you are going to upgrade go slow and change one thing at a time and run it at least a few tanks of gas before you make another change .

This way if it performs worse you can retrace your steps .

The first thing I would change is the variator and matching variator fan .
You really should get a variator locking tool and a torque wrench so you dont mess up your crank or a battery operated impact wrench can be used if your careful and you mark the nuts before you take them off and snug back to the same mark.
Very important to remember to slack the belt when you reinstall so you do not screw up your crank.

I have used malossi ,polini variators on my vinos .
They both work well and will give you a better top end and take off .
With the stock pipe you will need around 5.5 to 6.5 grams weights to get best performance .

What you do is find the best weight combo that gives you the best top speed and spunkiness on and off throttle and at take off.

Run this for awhile.

Pipes
Be prepared to upjet with bigger main jets and with needle adjustments to handle the higher rpms.

expansion pipes (yasuni r ,tecnigas Next R ,malossi flip,stage 6 )
higher top end but harder to tune the transmission for max performance

narrower power band that starts higher so you may need rublighter than 5.5 grams in the variator
You will also need stiffer clutch springs other wise it will roll we slow at take off for a few hundred feet and than pick up speed the stiffer clutch springs will start you closer to the power band so you get your spunky take off back

Street pipes (Tecnigas Silent Pro,Polini Speed ,Malossi Wild Lion)
Be prepared to up the main jet and adjust the needle in the carb
These pipes look like stock but have a wide power band like stock but they run higher rpms .
You can run close to stock settings for the transmission .


Tiny got solid results with just a variator and pipe combo

[bigmatthew86]

I have a Malossi multivar & a wild lion pipe on my vino. Throw on a good sport 70 kit & it’ll do 50mph all day on the flat. Takes off hard with the little tires too. Just a little louder & looks stock for a good sleeper combo.

[luke0000]

Further investigation lead me back to original steps on why the bike wasn’t starting, I did a compression test and only had about 89psi. After reading the owners manual it says that 85psi is the minimum. So I figured I’d order all the parts to get the bike goin

here’s the parts I ordered

Polini 70cc

Malossi variator kit

Main jet kit

New belt

And a yasuni z exhaust this is what worries me now as many people say it is almost equivalent to the stock pipe? What do you think about the z

The listing had said it could be used for 50cc and 70cc cylinders so I’m a bit confused
Thx

[bigmatthew86]

I’ve never ran the z, I had the r. That being said if you remove the restrictions from the pipe I suspect it’ll be an improvement over the factory pipe.

[Zino]

The z is far from a stock pipe 
It will be a great pipe to pair with your polini cylinder the powerbands pair nicely 

You need to get some stiffer clutch springs either medium or hard to go with that pipe
The power band starts later than the stock pipe and runs to a much higher rpm .

You also will need variator weights in the 5 gram to 6 gram range so you feel the spunkiest on and off throttle and best top speed

www.pedparts.co.uk/blog/choosing-a-yasuni-exhaust-for-a-sports-70cc-kit