Modern Vespa

Hello Vespa enthusiasts! PLEASE HELP, I am doing something wrong... here is my set up: 2004 Derbi Atlantis Bullet - Vespa ET2 engine, 50cc stock cylinder, 17.5 Naraku electric choke carb with 34 pilot jet and 90 main jet, air brass restrictor still on , Malossi 2000 multivar variator with 5 gram roller weights, did not used the stiffer white contra spring since its 50cc, polini clutch with replaced green stiffer springs, stock air box with malossi red sponge inside, YASUNI R exhaust derestricted....and going only 46 miles an hour 🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️ PLEASE HELP!!!

You're drowning it in gas. Way too much main jet.

What will your Jet suggestion be? Or just start lowering 88, 86, 84... I was advised to put From 5 gram to 6gram rollers and remove the brass metal between the air box and carb

try an 84 or smaller...take that brass restrictor out...

honestly you arent going to go much faster than 46 on a stock cylinder..maybe 50ish...how fast are you looking to go?

Thank you! I was advised from one of my scooter gurus to ad 6g rollers and remove the brass. Will let you know. I hope to get to 55miles, no more. If that doesn’t work...I have a Polini small covered open air filter...will try that too. Then may start rejecting...

Greetings:

The Holy Grail in 50cc scooters is to reach 50 MPH on 50ccs. You're pretty close as it is. Find a hill with a tailwind!

lol I am by the ocean on the east coast...no hills around here

that airfilter will take you there...you might need a jet larger than 84 though....do you have other jets just in case?

I have Polini kit 80-98...just tried polini filter with 90 brass on 44 miles 6g rollers🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️

try a smaller main jet with that filter...take the cover off that filter too...

Ok ...I tried yesterday many different combinations...open air filter or stock air box, 88,86 main jet, 5,6,7.2 gram rollers...I did end up with 5g , 86 main jet and stock box with brass on the carb 47 miles h With lowering the main jet size, everything seem to get better. I will try today 84 main jet. With lighter rollers I achieved the top speed of 47. Acceleration obviously it’s not as good as behavior rollers six or 7.2 g. I will try today 84 main jet. With lighter rollers I achieved the top speed of 47. Acceleration obviously is not as good as the heavier rollers six or 7.2 g. I just wanna break that 50 miles an hour barrier that’s it…

definitely try the smaller main..

is it better at 7/8ths throttle that full or does it pull hard all the way?

that brass disc can act as a restrictor too...

I use a temperature gauge to assist in tuning...trying to keep the temps between 195-210 really helps

Try a 78.

Ok . Just want to thank everyone in advance...I in counter another problem- twice. My starter clutch came out twice while riding with about 25 ml/h ... you can imagine the sound that came out from the clutch grinding into the teeth of the pulley. I thought that I blew up the engine!!! Just figured out that I am missing 2 little washers to keep it in place. It starts now without problem but I am not gonna try anything until I Figure that out...Then my plan is to keep lowering the size of the main jet. What I noticed - when I removed the brass on the stock air box or the Polini open air... scooter runs worst and loses about 2 ml/h!?!?? Thanks again. Will keep you posted. But if anyone comes Up with an idea or wants to share, please do so!

Missing number 4 washers...

your variator nut is not all the way down.... you need to tighten it more...that plastic fan is tagging the side cover.....also be sure you use threadlocker on that nut or it will spin off

let me know if thats as far as it goes

Yes the variator nut got unscrewed when the starter clutch hit the pulley ....and the plastic. Now its not ...but I have to figure out how to keep it in place without sliding out.

Finally! I Reached 59 miles an hour😳😳😳 I didn’t expect that much. The main problem was the belt. I have replaced the original Piaggio belt with better Malossi kevlar belt that also was a Little longer. Assuming that this is better, opposite It made things worse after I found out I swapped and put the original Piaggio belt.

My final set up is (Will start with parts are replaced): 84 main jet, 34 pilot jet, Malossi 2000 Multivar (tried rollers from 4g to 7.2) ended up with the 7.2 for quicker acceleration, polini clutch with green springs, Yasuni R Black edition.

Stock: 50cc, Airbox with red Malossi sponge, Brass air restrictor left on the 17.5 Naraku carb... For some reason it’s running better when the restrictor is on, stock contra spring on the clutch.

With this set up I’m doing 50-55 miles steady. I am at sea level.

My goal was to break 50, after I did 59 with 5 g rollers… I put the 7.2 g rollers and acceleration it so much better. I think I’m gonna put all the Fossett covers and enjoy it now… Done with the tuning for now... until the Stage 6 MK2 🤣🤣🤣

Thank you all for the help and support!

I forgot to mention, the bendix was broken replaced and it was all good.

Night shot

Way too many pictures if anyone needs a picture of the parts I got let me know. Thank you again!

hey there!...great job!....that pipe is the bees kneez...great pics

Hello dear fellow scooter enthusiast! Quick update...

I installed Stage 6 MK II Sport 70 cc cylinder with St6 intake system and reeds, St6 PWK 21 Carburetor.

OMG 😳... not sure why ...🤣🤦🏻‍♂️, that thing its a beast!!! I am not supposed to push it too much at the first few hundred miles...I supposed too, but I attempted a top speed test in a very windy day...bad idea. Went up to 66 miles on 2/3 throttle and decide it was not worth the risk. Very strong gust near the beach here...

That is a 70+ bike now, not sure if I am going to attempt another top speed test...till the summer, but that thing its a beast!

woo hoo! nicework

I bought a stage6 MK2 pro that im gonna install on my et2...sounds like you have a rocket there...

are you on the stock crankshaft?

my et2 doesnt like to have anything other than touring style pipes (pipes with an expansion chamber hit the bodywork)....your pipe is going to make this bike fly...

be sure you have some sticky tires and good brakes up front...upgrade them if you can..you will want to haul this bike down real quick...sintered pads at least..maybe an upgraded caliper and some ss lines...

keep us posted

Yes I am with stock crank shaft. I was advised by my friend who’s helping me with the build that with my Yasuni R exhaust I am limiting the Rpm’s to 11000, and my piaggio crank is strong enough but its near its border. If I had Yasuni c16 or 20/21 new crank its a must. Top power with my set up should start at 9500 and should be around 10 hp...currently with 5gr rollers, original contra spring, green Polini clutch springs. I got Stage 6 front racing pads, can you please put z links or model number to the brakes you are referring? I know this is a 70 + miles bike but the brakes are still 40 miles brakes...

Can you please list or link with your tire, caliber, disk, ss line recommendations? Thank you!

I have a different bike than you.... i have a vespa et2..only the motor is the same as yours so i dont know what calipers you can fit

sounds like your brake pads are good....and those tires look like conti zippies...which are sticky

I took my brake line off and measured it and had a custom stainless steel line made here https://www.coremoto.com/category_s/4085.htm

id just look for an upgraded caliper..if yours is a single piston, a dual piston would rock...and get a high end disc

does this have a shock in the front?..upgrading suspension will help with stabilty at speed