Labor Day Disappointment

[comradhuff]

Hi al,

So I got everything hooked up on my bike with no major problems except for what I would call a mid-size kink in my exhaust. With my wife filming (which may have been my first mistake), I made my first attempt to get the motor running. With no response, I realized that I hadn't opened the fuel valve (call it nerves), but it didn't get any better. I was getting a put-put noise, but it wouldn't fire up. After checking the forums, I tested my spark plug by leaving it exposed (I broke a chunk of one of my cooling fins trying to get the thing out) and riding in the dark. It produced a fairly consistent spark once I got going pretty fast. The spark plug also had traces of gas, so it appears that the gas is getting to it. I also opened up the clutch and tightened the flower nut to the point that if I hold the handle down it won't engage, but using the locking mechanism (which lets out a little slack) is too close and half-engages. So I'm pretty sure the clutch is not the issue. Where those were the two major fixes I saw on the forums I'm pretty stuck now. Someone mentioned that if there are dark splotches on the spark plug then it may mean that I have too much oil in my gas mixture. I think that might be the case, but I'm not sure. I mixed an 8 oz. bottle with 1.012 gallons of gas, so it doesn't seem like that would be the case.

Does anyone know what might be the problem? More importantly, does anyone know how I can fix it?

Thanks,
-Scott

 

[Kevlarr]

8 oz. to the gallon works out to 8 to 1. The engines call for 16 to 1 for break in. You have waaaaaay too much oil in your gas.

Get a bigger can and another gallon of gas, take your premix and add it to the fresh gallon and you should be just about right. Oh and make sure to drain the tank and the carb too.

 

[comradhuff]

I'm happy to try that if it's going to work, but I want to double check the math. There are 128 oz. in a gallon (8 oz. X 2 oz in a pint X 2 pints in a quart X 4 quarts in a gallon). 128:8 reduces to 16:1. Is this not how it works?

How do you drain the carb? I'm new at this (obviously).

-Scott

 

[Pablo]

8 oz in one gallon is 16:1

Tell us how your throttle cable bits are hooked up?

Are you getting good compression?

 

[deacon]

check for air leaks at the carb manifold connection that is the number one reason a bike will not start after a new build.

 

[comradhuff]

How would I check for leaks and how would I fix them? I thought I might have felt some puffs of air on my left leg as I was going so that sounds like it might be an/the answer.

I think I'm getting good compression. I thought I did the throttle bits as per the instructions. I can give more details when I'm home tonight.

Thanks for the help so far,
-Scott

 

[comradhuff]

So I picked up some silicone on my way home today and smeared it on the connection between the carb and the motor. I let it set for an hour, but it didn't make any improvement. I could still feel a puff of air on my leg as it was up in that area though. Is there anything else that might be leaking?

I also disassembled the throttle connection and it seemed to match my instructions. The cylinder moved up when I twisted the throttle handle when I had the carb off. What might possible be wrong that I should check for?

-Scott

 

[2door]

Okay, you've confirmed that you have spark. At least that's what I gathered from your original post. Now you need fuel and air. Is the choke open, lever down? Are you getting fuel to the carburetor from the tank. Pull the fuel line off the carb and open the petcock (valve) at the tank. You should have fuel flowing. Don't look for a flood of gasoline, just a trickle will be sufficient. Reconnect the fuel line, close the choke maybe half way, depress the fuel primer button on the left side of the carburetor a couple of seconds then start pedaling with the clutch lever pulled in. When you reach 5 to 7 mph release the clutch and tell us what happens next. You should feel the compression of the motor as resistance when you pedal if everything is as its supposed to be and hopefully the motor will start.
Tom

 

[comradhuff]

Wonder of Wonders:

So I adjusted the choke. My instructions had said to pull it all the way up and the markings on the engine are in chinese so I didn't know any better. I put it all the way down and took it out. When I let the clutch out, it didn't seem to do anything better, but then I used the throttle and it came to life. It was one of the best things to happen to me in recent memory (at least things that don't relate to my son).

Now my problem is that the engine won't idle. It'll stay going while I have the throttle engaged, but it won't keep running when I pull out the clutch. I fiddled with the choke and the idle screw (by no means systematically or extensively) to no avail. I also got the feeling that I should be getting more power than I am, based on what I've read. Is this something dealing with the throttle cable? I'll get to looking on previous posts when I have a chance, but any advice someone could give here would be great.

Everybody's help has been greatly appreciated. If any of you need a Marriage and Family Therapist sometime, I could repay the favor.

-Scott

 

[Ghost0]

OK now that you have got it to start, once it has warmed up you want to move the choke lever back up. Then your power should increase and then try adjusting the idle screw on the side of the carb. Turn it clockwise to increase idle and counter clockwise to decrease idle.

 

[2door]

Congratulations Comrad. You've joined the ranks of the motor powered. You can screw the idle adjustment screw in to increase the idle speed. If it bottoms out and the motor still will not idle with the clutch disengaged come back and let us know. There's several things to check. As for power; what are you looking for? During break-in, for the first couple of tankfuls, don't expect neck snapping performance. In fact, don't expect that even after break-in. But 20 mph should be easy to reach. Good luck, ride safe.
Tom

 

[2door]

OK now that you have got it to start, once it has warmed up you want to move the choke lever back up. Then your power should increase and then try adjusting the idle screw on the side of the carb. Turn it clockwise to increase idle and counter clockwise to decrease idle.

Ghost,
I think you mean choke lever down, not up.
Tom

 

[comradhuff]

Got it. It idles and everything. Turns out the idle screw needed to go in significantly further than I was able to do it by hand. I'm going to spend some time riding in around and getting a feel for it now and then I'll set to tweaking it. As far as power goes, apparently the reports of these 49cc motors being able to get up hills well must have come from people who never lived in eastern Connecticut. I guess I'll be getting a little exercise anyway.

Thanks again for everybody's help. These forums are a lifesaver.

 

[Ghost0]

Yes, 2door, I was going off memory and well see where that gets ya.

Comrad,
Do not despair, your engines horsepower will increase significantly over the next few tank fulls.

 

[jcchappy]

Did anyone notice that he said he felt puffs of air hitting his leg while starting the MB one kit we put together would not start. I say we but anyway the head was loose and the compression was blowing under the head out the side. sounds like you got it going now but if the head is leaking itwont run very well at all. yea and there's a definate point when the engine breaks in mine was a couple a tanks on the way back from town one day (3 miles to town) and all of a sudden it was like hitting a boost button it just smoothed way out and hummed right on up the power band.