New member needs help w/ 48cc 4-stroke (chinese)

J

jason4207

New Member
Hey guys! New member here. I joined to try and get some help w/ a recent project. I recently acquired a free mini-ATV. It was not running when I got it (that's why it was free), but I've been trying to resurrect it. I know it's not a motorized bike, but I was hoping to find some help w/ the engine itself.

I completely dismantled the electric start system trying to figure out how it worked (and why it wasn't working). I managed to get that going. I then proceeded to put some gas in the tank. I can't get it to fire yet, but before I proceed I need to fix another problem...gas leak. [side note...do not pour gas inside the garage...the garage stinks, and it starting to permeate into the house.] There is a small hose coming out the bottom of the carburetor, but it is broken off. I'm not sure where it's supposed to go, but I'm guessing it might be a return line to the top of the gas tank (pure guess...I'm still a novice mechanic, but pretty handy).

Anyway, any help I can get to get this little monster running again would be greatly appreciated. My 7yr old was so excited last night as I put some gas into it. He's really hoping I can get it running...so am I!

I searched online, and this model looks to be identical except that mine is red where this item is camo-blue.

Art.No.:RA-ATV009
1) Max. speed: 55km/h
2) Engine: 50cc, 4-stroke, air-cooled
3) Fuel: gasoline
4) Fuel tank volume: 4.5L
5) Ignition: CDI
6) Start system: electric or remote start
7) Transmission: chain drive system
8) Front / rear suspension: hydraulic pressure shock absorber
9) Dual suspension / shock-absorber system: dual swing arms
10) Tires: 145 x 70-6
11) Brake: rear disc (brakes the axle)


I can take some pics of the engine if it would help.

Thanks in advance!

Jason
 
Welcome.

You'll probably want to at least remove the float bowl and clean the carb out with some carb cleaner. Make sure the jets (little brass screws with a littler hole in it) are clear.

Yes, gas in the garage or house is particularly bad if you have gas heat, hot water, ect. The fumes can creep along the floor and ignite once it gets to the pilot.
 
Also, remove the spark plug, and ground it against the engine and crank it over to make sure you have spark.
 
Thanks for the quick response Joe.

Am I correct that the 'mystery' broken line goes back to the top of the tank? I'll post up some pics later tonight if it helps.

Where do you guys get spare parts? Does Auto-Zone or similar carry these items? Is there a good online outlet? I'm going to at least need some new fuel line, maybe a new float bowl, and a new spark plug probably wouldn't hurt.

When you say to remove the float bowl, do you mean to also replace it? Does it act as a filter?

Is there any instructions on how to clean the carb? Should I just blast cleaner into every opening?

My next step was going to test for spark, but I once I got the fuel leak I figured I should get that under control first. I'll be sure to make sure the fumes have dissapated before igniting anything, though. I'll probably push the ATV half-way down the drive-way just to be safe.
 
Don't know if the line is a vacuum line, vent line or ??? for sure.

What I meant was take off the float bowl, and clean it, and the carb out with some carb cleaner spray, since old gas collects in there and turns to funk.
 
If the mystery hose comes off the top of the bowl area, it could be just an "overflow"/ vent line to the ground. Someone with a sharper mind than me would know.
Sometimes a fuel tank has a "pressure" hose running to it, but I think thatis only on 2 strokes. (Refer to my second sentence):D
 
If the hose is on the bottom of the bowl it's a drain line. There will be a screw to open it.
It's a china bike, used to sell them. Check the jets as others have said, check the gas tank for flow. It should run. Those little starter motors are very fragile. Take it t an electric motor person. also do not over tighten it. The metal is weak and will break.
 
From the bottom of the fuel tank there is a small piece of hose going into the top of the 'float bowl' as you guys call it (I just thought it was a fuel filter previously). From the bottom of the float bowl there is another small piece of hose going into the carb assembly. On the other side of the carb assembly, near the bottom of the carb, there is another hose coming out. This hose is broken off. When I put fuel in the tank, and tried to start it last night my wife noticed the fuel on the floor. I found the fuel coming out fairly quickly out of this broken hose. The hose was too hard to pinch shut, so I pulled it off, and used a plastic bag and ty-wrap to stop the leakage.

I'll take some pics tonight, and post them up, so you can better see what I'm taking about.
 
fairracing31 said:
Welcome to the forum (^)
Click to expand...

Thanks!

Saddletramp1200 said:
If the hose is on the bottom of the bowl it's a drain line. There will be a screw to open it.
It's a china bike, used to sell them. Check the jets as others have said, check the gas tank for flow. It should run. Those little starter motors are very fragile. Take it t an electric motor person. also do not over tighten it. The metal is weak and will break.
Click to expand...

The little starter motor seems to be working fine. First I removed it and hot wired it directly to my car battery, and it came to life. Then I re-installed it and worked backwards through the starter switch assembly trying to figure out why the starter button didn't make it spin. There was a pair of wires going to the rear of the vehicle that were broken off. After I completely disassembled what appeared to be some kind of relay switch I determined that it was an electric magnet. Put current to the coil and the metal plunger drops which allows current to flow across the large copper contacts to the starter. I got that back together and working fine. Now I can push the button, and the engine spins...YAY! My 1st small victory. (^)

I was pretty excited to just get that figured out, so even though it was after dark, I went and got a gallon of gas. As I tried to crank it we noticed the gas leak. I have no idea if any of the gas is making it into the engine or if it's all leaking out of this broken hose.

Once I get the hose situation figured out, and get the carb cleaned up a bit I think it'll be time to test for spark.
 
Should I remove the carb to clean it? I'm worried there will be some kind of gasket that needs replacing if I do so, and I don't know where to get spare parts.
 
Here is a link to one of the forum's members "Norm" who did a good job explaning the workings and rebuild of carb used on the bike motors but will help with other carbs too. http://motorbicycling.com/f30/motorized-bicycle-carburetor-install-rebuild-302.html

If you pull the plug, the auto parts store can help you get the right one. Most times if you get fuel and spark, it will start. So like the others said, check the spark, and get the carb working. Good luck and welcome to the forum.
 
OK...I think I was confused earlier. I think that little thing b/n the gas tank and carb is a fuel filter and not a float bowl. The float bowl is actually part of the carb assembly, and is on the bottom, correct?

If so, and if the line is a drain line, then was it suppose to be broken off? I'll look for the screw to close it tonight. My gas tank cap has a small hole on a nipple. Is that just to allow air in or should a hose be attached?
 
Many off road bikes have a hose on the cap to vent air in without spilling gas on the rider. Both the drain hose or the vent tube is not critical to the bikes operation. If your float is sticking it will leak gas because after the bowl if full, the float shuts the gas off just like the float in the back of the commode in your bathroom. I would remove the carb and clean it and blow out the jets that deliver the gas when the needle is pulled by the throttle cable. If it is more then you want to take on, I would take it to a motorcycle repair shop. Now your son is interested, he will keep after you untill you get it running, I know that is the way my kids were:)
 
jason4207 said:
OK...I think I was confused earlier. I think that little thing b/n the gas tank and carb is a fuel filter and not a float bowl. The float bowl is actually part of the carb assembly, and is on the bottom, correct?
Yes.

If so, and if the line is a drain line, then was it suppose to be broken off? That could be a vent line or a vacuum line for the fuel petcock. I'll look for the screw to close it tonight. My gas tank cap has a small hole on a nipple. Is that just to allow air in or should a hose be attached? That is a vent to allow fuel to flow freely from the tank. QUOTE]

I would connect the correct size hose where it broke off, and run it above the carb. Put fuel in the tank and see what you get from there.
Click to expand...
 
TexasDav said:
Here is a link to one of the forum's members "Norm" who did a good job explaning the workings and rebuild of carb used on the bike motors but will help with other carbs too. http://motorbicycling.com/f30/motorized-bicycle-carburetor-install-rebuild-302.html

If you pull the plug, the auto parts store can help you get the right one. Most times if you get fuel and spark, it will start. So like the others said, check the spark, and get the carb working. Good luck and welcome to the forum.
Click to expand...


It's not that kind of carb he's working with.
 
Alright...learned a lot today!

First off, here are some pics of the engine still in 1 piece.

PC080200.jpg


PC080203.jpg


I pulled the carb out, and dismantled it. I used a whole can of carb cleaner on it, but it still looks a bit green. The bowl is still soaking outside. Should I use a toothbrush on anything to help facilitate cleaning? It appears to be a "PZ-16 50cc Carburetor w/ gold Hand choke lever". I think I'm going to order another bowl gasket. Should I also order the entire 4-stroke 50cc gasket kit? I only need (or can I re-use?) the one for the intake manifold.

I found the screw near the drain line and I think, as suggested, a longer piece of fuel hose propped up will do the trick. That's how it looks in some pics online for ordering a new one.

PC090203.jpg


PC090205.jpg
 
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50cc_carburetor_4stroke_logo.jpg



I haven't tested for spark yet, but the plug is an NGK-R. I think its a pretty high quality. Not sure if I should change it or just try to clean it...any advice?

PC090200.jpg


What do you think about the air filter? It looks kind of beat-up, and some gas got on it. Should I replace it or can I clean it? I have one of those K&N filter cleaning and re-oil kits. Is this the same kind of filter?

Does anybody know what this red switch does?

PC080204.jpg


Here is a list of stuff I've compiled for order: I found this place called ScooterParts4Less.com that seems to have a lot of the parts i need.

43cc/49cc chrome cone air filter kit $29.00 USD
12v Charger for Gas Scooter (round plug) $16.00 USD
4stroke Fuel Line green- $15.00 USD
4-stroke Carburetor Bowl Gasket (PZ-16) $3.30 USD
NGK Spark Plug (C7HSA)(1st class mail) $7.50 USD
4-Stroke Battery, 12v, 4ah $41.00 USD
4-stroke Oil Drain Bolt (magnetic) $7.00 USD
50cc Complete Gasket set $20.60 USD
Subtotal: $139.40 USD
Shipping & Handling: $6.00 USD
Click to expand...


A lot more than I want to spend (I think you can buy this entire atv brand-new for ~$350). Hoping I can re-use the air filter, spark plug, and the intake manifold gasket. I need a new battery as this one is swollen...I guess I also need the charger. I'm assuming its probably a good idea to change the fuel line, and I also need a fuel filter, but this place doesn't sell them (or I didn't see it).

Do these things have oil filters? Can I change the oil w/ some Mobil 1 synthetic 5W-30 that I have? What is recommended?

Please advise on what I should salvage, and what I should purchase. Also if I should look elsewhere for better deals...I don't mind buying from multiple places or going by an auto parts store. I'm trying to keep this project as cheap as possible.

Thanks again!
 
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