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Discussion Starter #1
So I bought used 49cc Cateye pocket bike. It didnt start so I bought a new carb. Now it has a very hard time staring. It sounds like I wants to and then I stops. It has spark, compression is good, there are no air leaks, all gaskets are good. Also, when it does run and I give it gas it is too weak to pull me and dies. Another thing is when the choke is up so the little air hole is blocking the choke. it wont start. Please give me some tips on what I should do. Thanks
 

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But who prays for Satan?
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As long as your description of what is happening is close to correct, it sounds to me like the engine is still starving for fuel, what type of condition are your fuel lines and fuel filter in? such as kinks, cracked hose, old dirty fuel filter, etc?

If you put a few drops (really just a few drops) of gas / oil mix right into the carburetor intake hole (the hole the choke covers) will the bike start right up and then die soon after? because that could help confirm a lack of fuel.

Nick.

So I bought used 49cc Cateye pocket bike. It didnt start so I bought a new carb. Now it has a very hard time staring. It sounds like I wants to and then I stops. It has spark, compression is good, there are no air leaks, all gaskets are good. Also, when it does run and I give it gas it is too weak to pull me and dies. Another thing is when the choke is up so the little air hole is blocking the choke. it wont start. Please give me some tips on what I should do. Thanks
 

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Discussion Starter #3
The fuel lines seem to be pretty good, the filter might be dirty, however there is a steady flow of gas from the gas tank to the filter. When I prime it there are no air bubbles. Would a lack of fuel kill the bike at open throttle because of the amount of air? I have starting fluid and it doesnt seem to make a difference on whether I spray it through the car, or take out the spark plug and spray it there. The bike still starts only sometimes. Could it be a bad coil? I mean there is definitely spark..
 

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Discussion Starter #4
I checked today and it seems like gas squirts out of the intake... Its a 49cc engine and the carb doesnt have the overflow hose. It just has one hose for the gas to get in and the other to get out with a primer. What screw should I try to adjust?
 

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It could be a weak coil, bad plug or wire connection. These cheap coils don't last long, seen them on eBay for $7.50. Pull the plug, w/ wire on hold the outside of the plug and crank the engine over and see if you have a good blue spark. You can tell by looking at the plug, if it gets fouled it will not work right. Make sure you did not block the pulse hole between the manifold and carb or it won't pump gas. Remember it's harder to make a spark at 15:1 pressure inside the engine.
 

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Make sure your gaskets are good and the tiny purgeports line up ,,make sure the fuellines are on right aswell as make sure the carb points the right way.....Also check to make sure the plastic intake is sealed at the engine block and isnt cracked.......

Id pull the fancover,,pull the coil,,,clean up the magnet if rusty and clean the coil thongs aswell and reinstall with an airgap between the coil and the magnet with a .020" strip of business card,,cereal box or index card

Then I would stick in a fresh NGK sparkplug BPM6A gapped to .030" mix up some fresh fuel,,pull the fuel clunker from out of the tank clean it up and add the fresh fuel mixed at 42:1

If it still wont fire-up replace the coil......Like EPR said its cheap and they go bad very often and for no apparent reason other than shoddy craftsmanship.........

Good Luck
 

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Discussion Starter #7
Well thanks for all the great tips. The fuel lines are new. new spark plug, no cracks anywhere and gaskets are good. Gas sprays out of the exhaust port when I try to start it. Not a lot but I can feel the spray. The spark is strong, but I will buy a new coil and try that. I will let you know, if that work.
 

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I would test the coil you have thru the spark plug in the dark, see what the spark looks like blue is Good, yellow is Bad. Double check everything before you buy new parts, could be a loose spark plug wire connection inside. does your coil have white or black filler?
 

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Discussion Starter #9
The coil is 2 inches from the bolts, and it looks like the spark is blue with white. Honestly I am all out of ideas. I tore everything apart and put it back on checking everything, and still at best it starts and bairly runs. Whats weird is when I tilt the bike there is a breaf second where it sounds like it works good, then it goes back to being weak. Still dies when I gas it
 

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Did it run the same w/ the old carb?? That's just weird, you have no reeds what about your crank seals in front of the main bearings in the cases?? Maybe the new carb is bad, it would not be the first time. Did you adj. the low and high jets on the carb??
 

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The coil is 2 inches from the bolts, and it looks like the spark is blue with white. Honestly I am all out of ideas. I tore everything apart and put it back on checking everything, and still at best it starts and bairly runs. Whats weird is when I tilt the bike there is a breaf second where it sounds like it works good, then it goes back to being weak. Still dies when I gas it
Do a compression test on the engine..Chances are you need a new topend.........
 

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Discussion Starter #12
The compression is very good. I adjusted the bottom screw to be 2.5 turns out, but when the bike is running and I adjust it, it doesn't seem to do much. How do know how much to adjust the top jet?
 

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Discussion Starter #14
All I can see is the pic. So I messed around and the bike started again. Once I gave it gas it made a loud popping sound, died, and woudnt start again. There wasnt a black cloud and the cylinder did not break. It still ha good compression.
 

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All I can see is the pic. So I messed around and the bike started again. Once I gave it gas it made a loud popping sound, died, and woudnt start again. There wasnt a black cloud and the cylinder did not break. It still ha good compression.

The pic is a video,,click on it........
 

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Discussion Starter #16
I went and bought a new engine and it still wont start. I am 100% sure now that it is something with my carb. Can someone please tell me what the stock tuning is? 2.5 turns out on the bottom , but what about the top?
 

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PBP SENIOR M!LKER
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Is the opening for the carb / Venturi 15mm or 12? I bought one once and it had the wrong carb all together... Measure the opening on the carb and make sure its 15mm... Are you sure your not blocking that pulse hole with a gasket and all the holes line up? Back Fires are not a good sign on these bikes... Bad ring cylinder or piston usually..
 

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Discussion Starter #18
It's a 15mm and I am not blocking the pulse hole. So I made the spark plug gap bigger and now it runs, not perfect but it does run. Stupid little things that cause such big problems. Also I tuned the carb and ended up cleaning my new carb out... Anyway everyone who hepled me get to the bottom of this I am truely thankful. You guys are awesome !!!!
 

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Have you done a compression check, my C1 felt ok with the pully start but only had 78lbs. not near enough and I tested 5 times. I pulled the cyld, the rings were all scatched up and had to hone the cyld and I have a new piston kit w/ rod bearing and all.
 
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