2 stroke engine

So far I got about one hour and ½. And the chain is staying on, and none of the bolts have came loose. I try to tune my CNS carburetor and the only way it will run right is if my main jet ( mixture screw) is almost close. ( to the right) So this means I need to get a bigger size jet. I rather buy one. My question is, can I use Dellorto 6mm main jets? And what size jets does a skyhawk yung dong CNS carburetor have. Also can I use a Clutch handle from a dirt bike, even if it doesn't lock. Thanks.
 
One thing I did is get rid of the plastic spacer, and made one out of copper. Now the carburetor is on there right, and not loosening air.
I finally got to use my sister camera, and I took some pictures. But I can't post them because, I can't connect that camera to my PS3. That really sucks, cause I wanted to show my bike. Oh well, I will find another camera that I can connect my PS3. Thanks
 
Remember the two screws are for idle only, if you can adjust the idle thats all they do. The e-clip controls mid range and the main jet size controls full throttle. The cns has a idle jet also.
 
Greg58 said:
Remember the two screws are for idle only, if you can adjust the idle thats all they do. The e-clip controls mid range and the main jet size controls full throttle. The cns has a idle jet also.
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??? So I don't have to change the main? ???
 
Greg58 said:
Remember the two screws are for idle only, if you can adjust the idle thats all they do. The e-clip controls mid range and the main jet size controls full throttle. The cns has a idle jet also.
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can you post pics of the idle jet for the cns carb not the one for the choke enrichment circuit????

As far as i know the idle screw only controls how far the slide is open inside the carb and that controls idle speed not the mixture
 
The screw close to the air filter is the idle mixture screw. If you take the carb apart you can see the hole behind the filter element and the small hole in the throat of the carb.
 
Greg58 said:
The screw close to the air filter is the idle mixture screw. If you take the carb apart you can see the hole behind the filter element and the small hole in the throat of the carb.
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I read some where if this screw is all the way to the right, that you will need to get a size bigger Jet. Is this ture. And what size Jet does the crab come with.
 
I have not checked mine for size, what I had to do when I built mine was to clean out the idle jet. I use my torch tip file set to gently remove the burs, on mine you could not see daylight through it. What you might want to do is run it for awhile and get it broken in then make adjustments.
 
I was looking at the tag, that comes with my engine. What I found out about my Jet engine. It is a PK80, 68.5cc. Everything on the tag looks the same as on the PK80. But also my engine looks exactly like the PK80. These engine are coveted for racing, high quality japanese bearings and a longer bent clutch lever for eazy pull. No longer being imported to the USA. I heard that these are very good engines.
(Pizhou Yongxing Gasoline Engine Factory
Engine Family: 9PZHS.0695pp
Engine displacement: 68.5cc
Date of manufacture: 11/2009 Exhaust Emission Control.
Thanks Piston bikes brnot
 
I still cannot get my bike to run right. I got a SBP muffler on it now. And it runs very good for about 5 or 10 minutes when I first start it. And then it loses all of it power, when I press the gas for the bike to go. What could cause this? Thanks :-||
 
Hi Hose13; sounds like the engine is running out of gas when you twist the throttle and add a load to the engine. Check for adequate fuel flow to the carb. Also, you might want to try and move the main needle in the carb up a notch to richen the fuel mixture. I doubt that your problem is of a serious nature. BMF
 
I think otherwise, when the engine is cold it requires a richer mix which rapidly becomes too rich once the engine is warmed up. What you could try is to warm up the engine to the point where you feel it lacks power and shut off the fuel valve thus the engine will go progressively leaner until it empties the carburetor float bowl. While the fuel valve is off, test the power the engine has but be careful : You do not want to keep the throttle wide open as a lean mixture makes the engine heat and also lack lubrication and you potentially could seize it. As the engine recieves a leaner mix from the carburetor you will most likely be able to tell whether it has more power or less power just by going WOT for a second or two.
 
If you are using the trash-can tank with the happytime, you must ditch the in-tank filter screen and chinese petcock. You can get a 10mm brass fitting with a 1/4" barb, and a $5 in-line fuel shutoff, and a $3 inline fuel filter. You should be all set, and if not, it will save you some pedaling down the road.

Hoze513 said:
I still cannot get my bike to run right. I got a SBP muffler on it now. And it runs very good for about 5 or 10 minutes when I first start it. And then it loses all of it power, when I press the gas for the bike to go. What could cause this? Thanks :-||
Click to expand...
 
Hoze513 said:
I still cannot get my bike to run right. I got a SBP muffler on it now. And it runs very good for about 5 or 10 minutes when I first start it. And then it loses all of it power, when I press the gas for the bike to go. What could cause this? Thanks :-||
Click to expand...

Start it up, then remove the filler cap, and see if this helps.
 
Kinda sounds like there might be an ignition problem. I've seen it a lot. Runs great until it warms up. Wouldn't pull the hat off you're head after that. I could be wrong it wouldn't be the first time.
 
happycheapskate said:
If you are using the trash-can tank with the happytime, you must ditch the in-tank filter screen and chinese petcock. You can get a 10mm brass fitting with a 1/4" barb, and a $5 in-line fuel shutoff, and a $3 inline fuel filter. You should be all set, and if not, it will save you some pedaling down the road.
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Nope, Iam using a kit I order from piston bikes. And I look inside the tank before I install it, and it was very clean. No rust. Thanks
 
Bicycle Motor Fun said:
Hi Hose13; sounds like the engine is running out of gas when you twist the throttle and add a load to the engine. Check for adequate fuel flow to the carb. Also, you might want to try and move the main needle in the carb up a notch to richen the fuel mixture. I doubt that your problem is of a serious nature. BMF
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I check the spark plug and it's not oily no more. So it could need more gas some how. But when I move the needle into a richer area, it runs worse then it is already. Right now my needle is on the second spot from the top. Thanks
 
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