23mph...Whats wrong?

Rachtak said:

Ive ridden my MB for the past week about 50 miles.
I am 145lbs but the bike wont go more than 23mph at full throttle.
Its a DAX 62cc so I assume that it should be capable of at least ~30.
I live at 23feet above sea level.

I've checked the carb slide and its defiantly going all the way up 100%. I ride with my choke completely open (I've taped it down since I go alot slower when its not all the way open).

I've checked everything that can go wrong and the only thing that I can conclude is that the source must be at the carb. However, since I dont know anything at all about how the carb works or assembly, I dont trust myself with tearing it apart without knowing what to look for.

Is there a video out there that I can follow to open up my carb and get to the source of my problem?
Also, I dont know what the "idle speed" screw does but could that be affecting my speed?

Do I need to order replacement parts for stuff in the carb? and if so, from where?


(On a side note), the parts that connect the gas tank to the carb (valve thing, and tube) are dripping gas when the motor isn't on. Its very little but still very annoying. Are there any parts I can order that will fix this?

Thanks alot in advance.

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Just give it some time. Mine didnt go over 24 til after I put on some miles. Some motors even take longer than 50 miles to break in.

Is your engine running good at least and is your only problem is not going over 23MPH??

If you take a look at the sponsors for this site there are many places you can get spare parts from just look around.

I would suggest getting new fuel line and a fuel filter, you can pick those up at your local hardware store.

Hope this helped.

Tcams

Re: 23mph... I think somethings up?

here is the best I can do for taking the carb apart.

http://motorbicycling.com/f39/motorized-bicycle-carburetor-install-rebuild-302.html

the idle speed only either speeds up the idle or slows it down.
the choke can be fixed to not come on by its self. take off the air breather there is a small nut on the choke you can tighten the nut very slightly to make it a little tougher to move the choke lever.
what does the spark plug look like nice and tan or black and oily?
where is the c clip n the needle stock is #2 slot from the top or fat end.
you have only 50 miles on the bike? if that is so then I think its not broke in yet.
the leak from the fuel valve did you put the little red washer between the tank and the valve or put a little thread dope on the valves threads.
safety wire works good on the line for leaks the hose fitting if you look at some of my posts you will see the wire wrapped around the fuel line fitting then twisted to seal the line, its easier to use and cheaper than hose clamps or wire ties.
your engine is from Dax he sells parts for the carbs you can look at his site for parts for the carb
I do not know the fuel mix ratio your using but if its less than 20 to 1 its very oil rich and will perform less. 20 or 24 to 1 is a better starting point for breaking in. my opinion.
what gap is your spark plug 0.024 to 0.028 is good. Or if you run lights then 0.017 to 0.020 is what I run on my engines.
Give your bike some time if you have only 50 miles on it it will take up to 500 miles for them to get broke in some will sooner than that .
Have fun and keep riding it.
norman

Just so you understand what we mean by broke in the rings have to wear in to seal better for compression which basically means the pressure inside the engine is not what it will be once the rings seat in. I was shocked how slow mine went until after about 100 or so miles.

george_n_texas said:

Just so you understand what we mean by broke in the rings have to wear in to seal better for compression which basically means the pressure inside the engine is not what it will be once the rings seat in. I was shocked how slow mine went until after about 100 or so miles.

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Me too. Bigger difference in accelleration. When your motor is broke in you will definatly know it. It will sound much better.

Have fun

Yup.. after break-in you'll really love your bike.. It'll go fast and sound great..

BTW, break in periods seem to vary wildly - manufacturing, type of oil & mix, riding habits, random chance... all seem play a factor in how long it takes. Mine took close to 300mi before it figured out how it was supposed to run and snapped out of it.

Other than what Norm suggested, be careful "fixing" or modding it too much before it's done breakin' in - you may well be fixing a problem that doesn't exist, creating one for later

Also, what sprocket are you using? I have the 40? (its big) with a 20 inch wheel, its quick but it tops out at around 29. Thinking about a smaller sprocket because i like the look of the wheel.

A 36 tooth sprocket definitely ups the speed- but also (and I'm always harping here) TIRES!!! Most mountain bikes have dog tires- knobby 1.95 width or 2.225 Heavy and sluggish- too much rolling resistence!

You see bike racers with narrow tires- that's for weight and roll- we have a very small natural motor- less than a horsepower, and our 2 cycles haven't much power either- they do respond to the tenets of racing and touring bicycles.

get some smooth tread street tires- 1.75 or 1.50 and a smaller sprocket (at your weight 36 should be NO PROBLEM if you aren't mountain climbing- if you want to ride trails you have to sacrifice street speed. That's the diff between a dirt bike and a street cruiser in the motorcycle world.

Before the motor kicks over, you'll notice the difference peddling. Plus you'll find the vibration MUCH less and the ride more comfortable- 1.75 are not popular and a lot of shops sell them for ten and twelve dollars- and you can still use your old tubes.

it also depends on your gas! how you mix it etc.