Final jetting decision ???

Ok so ive been thinking for some time now and have been getting different opinions off people but if everyone could post here so i can see them as a list it would be great. Basically i have a zip 2 stroke 50 cc and i dont have the right jet in it. Its running ok ish but its making horrible sounds when i go at 10 mph and sometimes when i accelerate ive been told its definitely the jetting. So my question to you is should i take it to get dynoed which will be 50 quid + because ive spoke to the guy over the phone or should I get one of my mates too fit it who are motorbike mechanics level 2 ? Will it ruun just as well if i get them to fit it or should i go and get it fitted so its precise. I could do without spending 50 quid on it tbh and rather just pay a fiver tenner for my mates time. Let me no what you think, thanks

 

if its only the jet its not reall that hard to change atall, just remove the carb and unscrew the float bowl and remove the old jet and place the new one where the old one went, its finding the correct jet for your setup that will be a little harder, start higher and work your way down, get your mate to show you how to do it do you know for future reference and then work from there

 

Thanks mate, i just had a little go of getting the carb off. It was easy disconnected a few wires then it basically came off but a long wire nearer the front end of my ped was attached to it do i just unscrew the screw on that ? Look at this picture bottom right just above the blue writing http://a3.sphotos.ak.fbcdn.net/hpho...793666447_1016158174_3078859_1509779865_n.jpg

 

thats the throttle cable going into the slide, if you dont know what your doing mate then stop where you are and leave it until someone who knows what they are doing can do it properly

 

ok i really wana do it cas i think that i can, you see the throttle cable do i just unscrew it to disconnect it cas then the carb would be off. Also when im changing jets etc do i just simply change them put the carb back on try it if its shit change it to another jet or is it more complicated ? If you can tell me i would really like to know although ill probably just get my mate to do it

 

Buy a box of jets!! Paying £50 for the most basic of set ups is just crazy. Changing main jets is one of the first complicated things I did on my ped and tbh I felt much more confident fixing bigger stuff afterwards.

Changing jets is just literally undoing the screws on the bottom of the carb, checking what jet is in it, and changing it depending on how its running. After the first time you do it itll be 10x easier i guarantee. If you start with a high number apart from running shit there is NO risk of anything getting damaged.

Even if something strange happens that is what the forum is for lol..

http://www.scootershack.co.uk/threads/scooter-carburetor-jetting-guide.2467/

 

yeah you undo the top and slowly pull out the slider and needle that is attatched, let it up slowly though as there is a spring right underneath. as for changing the jet remove the old one and put the new one where it came out from, then put the carb all back together and go for a ride and see how it is, would be better off doing a plug chop and seeing how well it is running

 

Yeah just unscrew the plastic bit on the top of the carb and the throttle slide will come out. If youve disconnected all the pipes then the carb should just come off after that.

 

ok thanks lads and what are plug chops and how do you do them loool ? Also what is it best to start on in jet size a 60 - 78 box should soon be arriving in the post and do i put my air box on before or after ive fitted the jets

 

Plug chop is just basically running at full throttle for a few mins and taking the plug out to check the colour which will I've you a idea of how the mixture is. I think there's a guide about that will tell you about the colours and what they mean

Start at maybe 75 and work your way down. If its madly rich or lean add/drop 2-3 sizes, when it feels like its getting near bang on do them 1 at a time etc

 

ok mate and after every different jet i put in do i need to adjust anything else like the air mixture screw or anything ? In other words is there anything else i need to do in the process. If you could sum it up it would be brill cheers pal

 

told ya at facebook how to do it mateeeeeeeeeeee

 

the air screw will affect jetting just make sure it's set right (2 turns if I remember) and leave it be. Changing the main jet is literally just changing the jet.

As you tune further you might have to start messing with air screw and needles etc but for now leave anything else as is