Same o, same o - JET topic

Hello guys, im new here but i have experience with bikes so im not so stupid and understand whats going on in the scooter, but I have one problem with my brother new scooter Piaggio NRG 2011 carburetor. Can you please help me what main jet to put on the Piaggio NRG 2010 carb. without restrictors and with Leo Vince TT pipe. Stock 49cc. Is it matter where i live for the main jet (sea level) ? Im 550 up from sea level and humidity is around 50 to 70% in the summer. I use stock air filter and dont want to change it with open air filter (sport). So what main jet is best for this setup:
49cc stock Piaggio NRG
LeoVince TT - Restrictor is removed from the exhaust. Im not installed yet the rollers and the springs from the complect, but i will when i set up the main jet correctly.
I understand the rule of the 5% or 10% for the jets but many people told me to install jet from 75 to 79 and to see what will happen ?! The stock jet is 53. All restrictors are removed.

 

around 65 - 68 main jet i would say for a leo vince tt

75-79 jetting your looking at a 70cc sport cylinder jet set up there, and on a stocker 50cc thats just going to be very very high.

Try with a 68 jet see how you get on then if need be come down in jet size a little ( keep it more on the rich side is safer), you will want to add the rollers as soon as you put the new pipe on and jet up. the leo vince has a somewhat tight powerband spread and is not to easy on variator tuning ( 5.55 - 6g rollers) as you have around 800rpm spread to play with , so install rollers at same time as pipe goes on then install jet and start tuning from there on.
power peak is at around 8500rpm and 9300rpm with the leo vince.

if you find it really rubbish between 0-30mph its your rollers and contra spring - clutch springs, you wanna be opening that clutch out at around 6000rpm onwards so a 1k contra and 1k-1,5k clutch springs.

 

Thanks for the quick answer. Richer is safer that is the rule The exhaust is installed but the rollers are stock, and the springs are stock.
I have a set of 5.7 grams with exhaust should i put it now or later when i changed the main jet ? Also with the exhaust came Piaggio Soft Blue little springs. When to put them after the rollers or everything on once ? I tune the bike for my brother and he is 100kg. ,also he wanted to be faster from 0 to 60kmh so he can be faster then the traffic from the traffic light (im not sure that how you said this )

 

yes install the springs now with the new 5.7g rollers.

install the new jet say a 65 jet ( 68 maybe a little to much) and have a couple test rides, see what its like , your main jet kicks in from 3/4 throttle to wide open throttle. the throttle needle inside the carbs throttle slide is 1/4throttle to 3/4 throttle ( just move the needle clip down one ring to make it richer ), for idle its the air/mixture screw.

keep an eye on engine temps and as always air on the side of being a little rich on the tuning .

 

Thank you. What about the needle - stock position was highest ( lean) and i put it on the second from the top, but with this jet 53 its really a pure nightmare and i can run faster than this bike .. I will try this what you said. Most important for me now is to get the correct main jet and from there is easy. Thank you again. It's possible not to answer in a short period or long ( some months) because here winter is falling and the temperatures are low and the setup of the carb It makes me worried because of the weather.

 

hot summer months can be more a pain as the air is alot thinner when its heated. in the winter the air is more dense . long as your keeping that idea of rich is always good thing you should be ok.

65 jet, but you may want to come down to something like a 60 jet, see how a 65 jet pans out first , and make sure those rollers are put in so you have a little lighter weigh in the variator to help that clutch come out sweet at around a good rpm range. going to take time to jet and tune but you should be ok and find a sweet spot.

needle setting you have now sounds a lot better. in stock form companys always make the bikes run lean, you have just made the scooter a bit more richer between the 1/4 throttle and 3/4 throttle range nothing to worry about and better for the motor to

 

Im worried about the fuel consumption. On my previous bike ( beta ark 70cc mhr) needle setting from one to one make big difference in fuel consumption ( but then i didn't know anything about main jet).

p.s. And what about the two pipes with antifreeze in the carb ? They are worming the carb, should i remove them because every time i need to change the main jet it's get real mess.

 

Derestricting any 50cc twostroke is going to see a slight MPG lower rate instead of the 70mpg its going to be around 60mpg.
that is something one will get used to and depending on rider to. that is the pay off for that extra speed a slightly lower mile to the gallon

need to explain to little brother that if he keep that throttle open wide all the time he will be gulping more fuel, but if he rides sensible he will have that little extra speed and get away at the lights but will not be filling up every few days. your 70cc MHR is very differnet to a derestricted NRG 50cc its not going to be drinking fuel like the MHR kit did so dont worry much.

what i would do is drum into little brothers head to check his two stroke oil bottle every few days, running out of that will cause more damage than using a tank of fuel in a week . running out of oil and seizing the engine will cost a huge amount to correct .

 

Yes he know that. He is 6 years bigger than me. I have''d Beta Ark mhr in the past, now i have Benelli Velvet 250cc 4t. The lightest 250cc scooter.

p.s. check the upper post for the antifreeze.

 

unplug them for time being while you install main jet, then refit them. they warm the carb up in cold weather and the fuel to, helps stop carb icing

 

Good evening guys. Today was the day. The weather was fine and i have time to install the new rollers 5.7 gram , little blue springs on the clutch and 68 main jet. Then adjust the air screw and the bike is like never was before. Result is perfect. Good start, good top speed (90 km/h on the bike speedometer). I have smaller main jets 65 and 62 but maybe in the summer or spring i will setup it again if i am not satisfied from the fuel consumption. Thank you very much for the help.

Setup is:

49cc stock Piaggio cylinder
Leo Vince TT
5.7gr. rollers from the complect with Leo Vince (19x15,5)
Little blue springs from the complect Leo Vince
68 main jet
Postion of the needle second from top.

 

sounds like a little fettling has done the job from that poor runner to giving the scoot a new lease of life.

fuel usage is always going to go up once you derestrict a 50cc but its not as bad as one thinks, your brother should be happy with the results you have gained from the new parts fitting and the small upjet .

your very welcome for the help and advice, being a comunity of scooter /bike owners we all help one another because we have one thing in common and thats enjoying the open roads and the freedom of owning a scooter/bike.

Ride safe milenkatara and brother and enjoy those open roads together

 

Yes the NRG starts a new life from today. Thank you.

11204km on the dash.