Aerox problems

Hello everyone, I'm new to this forum. So, I have an 2000 Yamaha Aerox YQ50, I bought it like 3 weeks ago and it has some problems. First of all, I bought it as a 50cc with an aftermarket exhaust pipe for a 70cc kit and it was very slow (60kmh max) and it was very slow while pulling off. So I had another pipe laying around (LeoVince Titanium) so I put it on it, it is a little bit faster and quicker while pulling off but still it doesnt go faster than 70kmh. I decided to take the cylinder out, so I'd see what parts does it have inside as i have in mind to make it 70cc (i have a seized polini kit), so i opened it and it has the standard cylinder but rebored to 46mm and a standard crank. I got it back and running again, and I feel a small increase in power. The problem is that the ped doesnt increase revs while accelerating. It does increase revs but very slowly (even slower with the Lorenz 70cc pipe). Everything is standard except the pipe and the piston & cylinder, so i need some advices what can I do to it to get it increase rpm faster. Other than that, it didnt have a battery when I got it, and the guy told me it needs a battery so the indicators, starter, cluster display and horn will work. I got it a battery but they still dont work, and i actually found out it doesnt have a horn at all. After a while the oil light came on but it was with very low brightness. When i switched to high beams, the oil light brightness increased to normal and the cluster display started working (going up and down with the temperature and fuel level). When i put oil in it and the oil light turned off, the display stopped working too. Does anyone else have any similar problems? Any help will be apperciated.

 

Roller weights govern engine rpm.

lighter roller weights will allow the motor to build up its rpms before the clutch engages, having the rpm at an optimal range when your pulling away is good. usually 5 gram or 6 gram weights are a starting point, it maybe that you have stock roller weights in the variator and thats causing your slow pull aways.

usually when your bore up you need to add more fuel and air, so we tend to add a larger carb and/or we adjust the flow of fuel to the engine by putting a bigger main jet into the carb, a bigger jet means more fuel .
with these changes your going to need a little extra oil the stock autolube system just wont feed enough oil, most folks will blank off the autolube and do a straight to the tank premix where they add a certain amount of fuel directly to the petrol in the tank.

 

Thank you very much, I apperciate it. I will try and change the roller weights and see if its better. Other than that, does anyone know what should I do for the electrics?

 

check the fuses in the aerox , could be a faulty fuse. could also be a loose ground wire

 

The fuse is okay, power goes through, but where could the ground wire be connected?

 

ground wires tend to terminate direct to the scooters frame. i could not say for sure as i have not owned an aerox myself.

you could probe the lighting looms to see if there is a continuity problem somewhere in that area. checking the hi-lo wires ie wires from the switches to the headlamps , say white hi/low wire from main light switch to white wire on headlight bulb mount ) its going to be time consuming checking each wire is in continuity and has no breaks.

if the dash only lights up when say highbeam is turned on theres a ground problem somewhere ( headlights are pos and neg feed ie live-ground ) as the main highbeam works as its grounded but the dash does not because somewhere in the line the ground is faulty/loose.

Not sure if this is of help its a YQ aerox service manual and will have the wiring schematics

https://scootergrisen.dk/scooterhjemmeside/download/yamaha_aerox_servicemanual.pdf

 

Thanks to everyone who replied, I'll get the electricity sorted out, other than that, I have put new lighter roller weights in and a new belt. It is very slow while taking off, but when it takes off like at 5-10kmh it increases rpm very fast and its top speed its still like 65 kmh.. And also i found out that i have aftermarket clutch springs which one of them is yellow (i think malossi) and two are blue, somebody was fucking around with this scoot and im already starting to hate it...

 

Very slow take off could be weak clutch springs engaging too early. Slightly stiffer springs will ensure the engine revs get higher before clutch engages and pull away will be stronger. What revs is your bike doing when the clutch engages?

 

I don't know it doesnt have a rev meter but it is pretty low, so next thing im changing is clutch springs and i will try a bigger carburetor

 

So I've rebored my Polini Corsa cylinder, put it all together on the bike, it started immediately and it runs like a charm, but I have noticed that when i go full throttle, the revs go up and then slowly go down and then it just revs up and up slowly.. what could be causing that? Is it a small carburetor, do i need bigger jets, is it something with the transmission..? Thanks.

 

if you have had the bore honed out / re-skimmed ( bored out) you need to re-jet. the reason is you have added a very tiny amount of capacity by doing that, so you need to re-tune the carb to take that into account.

try knocking up one on the main jet or two on the main jet see if that helps ....... full throttle = main jet so i would say your a little low on mainjet now and it needs a slight tweeking to get you back again.

 

Thank you, i will try it out.. And does anyone know why it keeps snapping my belts? When i bought it i noticed that it was a little scarred on the inside side, so i put a new one and it got scarred on the same side so i left it like that and it snapped, yesterday i put a new one and idk whats the problem..

 

possible your variator is worn and roughed up to much and this causes belt wear to be excessive.
or the rear clutch pulley face is worn and this inturn is causing belt to wear excessively , check front and rear pulleys for roughing

 

Everything is nice and smooth, no rough spots, can you tell me which belt size does the Aerox YQ50 have? It had 743 on it when i bought it and the new ones i put are 743 too, maybe its the belt number thats wrong?

 

747 is what most shops are saying ,

 

Thank you for the information, and i have another question. I had a piaggio nrg a year ago and i have clutch springs from it, theyre white malossi and theyre driven like 50km or less, will they fit on the aerox?

 

not sure on that one, i would measure them up may find they are slightly different lengths - widths but still measure them up to see if they are the same size as stocks in aerox

 

So i found another ones laying around, brand new malossi black clutch springs, i put them on the scoot, its kinda better but its still slow on taking off.. So i think i might put the white ones on the scoot?

 

Tried the white ones, put back the original belt (looks used for a longer time) because the new one i put was a bit thicker and the clutch was engaged almost all the time.. With a white malossi clutch spring and little malossi white springs it has a kinda better accelerating(takes off at higher revs) but now the problem is: when its cold, if i start it and ride it hard immediately it goes pretty damn fast, but when it gets warmer and i stop on a stop light or something, its accelerating very slow and not only that, it doesnt have a top speed too.. It just doesnt rev more like when its cold.. Some will say its the choke that gives it more fuel when its cold, but not because the choke is electric and unplugged because this scoot had a manual choke originally..

 

possible the electric choke has failed Mario buddy and its sticking .

whats the engine temps like when its been running hard , is that top end real hot ? and are you running the right oil mix to the tank , you wanna be around the 33:1 ratio on oil mix so around 156ml-160ml of oil to a full tank of gas