New Rider
Currently Offline
Posts: 34
Likes: 0
Joined: Apr 16, 2013 12:07:25 GMT -5
|
Post by relaxinrob on Jun 13, 2014 6:54:12 GMT -5
I have a 50cc gy6 139qmb scooter. I work on scooters all the time, but i cannot get any speed out of this particular scooter. I have adjusted the valves, jetted the carb to an 80 jet, installed the orange coil and cdi, tuned the carb and still no more speed. It will rev up as you are taking off then just settles down and will not go over 30. I haven't messed with the variator yet. Do you think I need lighter rollers to give it more rpms?
Thanks for your help. I am at a loss on this one
Rob
|
|
|
|
Post by JerryScript on Jun 13, 2014 10:45:45 GMT -5
Can you post a picture of your CDI, it may be restricted.
Also, take the variator out and weigh one of the weights. Heavier weights usually give better top speed, but too heavy can cause it to spin out too soon. Lighter weights are used for faster takeoff.
|
|
|
|
Post by alleyoop on Jun 13, 2014 13:04:00 GMT -5
I hope you realize a STOCK 50cc will only do 30 maybe if your lucky little over. The motor only are pulling less than 3 hp.
Also sticking a #80 main jet your actually killing some power that is to much fuel for a stock motor. The 50s usually come with a 18mm carb and a main jet anywhere from 62-69 or so, you can try a #75 main jet. Your only recourse is to work with the CVT little bigger Variator and weights. All the other stuff CDI, COIL, Iridium plug will give you a good spark easier starting and if the CDI is advanced a little more power but nothing dramatic.
Alleyoop
|
|
|
|
Post by geh3333 on Jun 13, 2014 18:12:36 GMT -5
Can you post a picture of your CDI, it may be restricted. Also, take the variator out and weigh one of the weights. Heavier weights usually give better top speed, but too heavy can cause it to spin out too soon. Lighter weights are used for faster takeoff. I know many say lighter weights are for better takeoff and heavier weights are for top end but I def don't agree with that . I understand the physics behind it but I always say it's a tuning process . With a new belt I use 10 gram weights if I go up .5 grams I lose top end and if I go down .5 grams lose top end unless I want to run at redline. Also if u go heavier u can keep some of your takeoff by adding a heavier main clutch spring , It also depends on the weight of the rider . And let's say I being 210lbs let somebody ride my scoot who weights about 130 , they will probably need to up the weights to keep from redlining or if it where the other way around I would need to go lighter to gain top end. The only thing that is a certain is going heavier and u will lose takeoff and lighter u will always gain at takeoff but that dosent mean u will lose top end. |
|
|
|
Post by JerryScript on Jun 14, 2014 0:00:59 GMT -5
Can you post a picture of your CDI, it may be restricted. Also, take the variator out and weigh one of the weights. Heavier weights usually give better top speed, but too heavy can cause it to spin out too soon. Lighter weights are used for faster takeoff. I know many say lighter weights are for better takeoff and heavier weights are for top end but I def don't agree with that . I understand the physics behind it but I always say it's a tuning process . With a new belt I use 10 gram weights if I go up .5 grams I lose top end and if I go down .5 grams lose top end unless I want to run at redline. Also if u go heavier u can keep some of your takeoff by adding a heavier main clutch spring , It also depends on the weight of the rider . And let's say I being 210lbs let somebody ride my scoot who weights about 130 , they will probably need to up the weights to keep from redlining or if it where the other way around I would need to go lighter to gain top end. The only thing that is a certain is going heavier and u will lose takeoff and lighter u will always gain at takeoff but that dosent mean u will lose top end. I can't argue with fine tuning such as you have done, and I don't mean too. Just trying to get some info on his variator to see if we can help him get more speed, since he said he hadn't looked at it yet. |
|
|
|
Post by geh3333 on Jun 14, 2014 0:23:14 GMT -5
I apologize if I sounded like I was being argumentative it's hard to post some things without sounding that way . For the most part I think it's thought of as being how u explained it . I tend to look into things alittle to much sometimes. Lol . Just don't want u To think I was being an a-s.
|
|
New Rider
Currently Offline
Posts: 34
Likes: 0
Joined: Apr 16, 2013 12:07:25 GMT -5
|
Post by relaxinrob on Jun 15, 2014 13:08:55 GMT -5
I think I need to try some lighter variator weights because it will not get up to max rpms unless it is on the center stand. It labors when on the ground. If I had some more rpms, it would go faster.
|
|
|
|
Post by alleyoop on Jun 15, 2014 14:23:51 GMT -5
Yes, your are correct if it labors getting up to speed the weights are to heavy and climbing to early up the variator face which kills your rpms and will not let the motor turn freely enough to produce more rpms.
Alleyoop
|
|
..BAD TO THE BONE..
