80 c.c runs best on half choke..whats wrong ?

rumme

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Jun 11, 2008
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does this mean I need to lower the needle clip / raise the needle in the carburetor one notch to allow more gas in the carb > ? I did modify the muffler by cutting out the inside baffle rod....leaving only 2" of rod inside the muffler.
 
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Mar 16, 2008
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If you need to close the choke, you probably have an air leak at the intake manifold. To check you can spray some WD40 near the area while the bike is idleing, if it revs air leak.
 
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Then the clip on the needle needs to be lowered to raise the needle to allow more gas so that the choke can be opened. More gas = more air, so raisnig the needle should allow you to open the choke all the way... What position is the clip on now?
 

rumme

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Jun 11, 2008
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i didnt check its position when i assembled it last nite....whatever stock postion is.


I did cut the baffel rod inside the muffler down so its 0nly 2" long now.... iM PLANNING ON drilling two 1/4" holes at the end of the muffler baffle tommorow and then lowering the needle clip 1 lower to see if it will make the engine run smoothly with the choke fully off ...
 
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Well let me know how you make out when you move it. I think that will solve your problem. Like I said too little fuel meens you have to close off air to balance the mixture so I'm pretty sure that will solve your problem......Just one more piece of advice I would get the bike running the way you want it BEFORE making any more modifications, that way you have a baseline as far as performance to start with.....Just my opinion.....
 
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adjusting needle should Do it. ( if no blockage in carb or fuel supply)

I agree with MrRight.
Mods should be done after Things are running smooth and up to par.


As my shop teacher always said 25 years ago " KISS "
Keep,,, It ,,,Simple ,,Stupid.. ( According to him Back then All of us in class where stupid).

cheers

Bob
 

rumme

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Jun 11, 2008
Messages
45
just tryed it....


first thing I did was to make sure there wasnt any air leaks around intake/ carbereutor.....

then I lowered the needle clip 1 increment....no change...I then lowered the needle clip to the lowest position down, 2 increments and the engine still runs best with the choke lever in the middle instead of all the way down.


any other ideas to fix this problem ? Or is it allright to leave the choke lever in halfway position and just run the engine like that all the time ? Id rather get it so its working correctly though.

Keep in mind this is a new engine and I havent ran a full tank of gas thru it yet....and I also took the baffle out of the muffler and cut the inside rod down to 2" then put it back together. Is it possible that I need to drill two extra holes in the back of the muffler baffle to remedy this problem ? Or maybe I need another jet ?
 
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just tryed it....


first thing I did was to make sure there wasnt any air leaks around intake/ carbereutor.....

then I lowered the needle clip 1 increment....no change...I then lowered the needle clip to the lowest position down, 2 increments and the engine still runs best with the choke lever in the middle instead of all the way down.


any other ideas to fix this problem ? Or is it allright to leave the choke lever in halfway position and just run the engine like that all the time ? Id rather get it so its working correctly though.

Keep in mind this is a new engine and I havent ran a full tank of gas thru it yet....and I also took the baffle out of the muffler and cut the inside rod down to 2" then put it back together. Is it possible that I need to drill two extra holes in the back of the muffler baffle to remedy this problem ? Or maybe I need another jet ?

Are you sure The carb is clean and not blocked .( Main jet isn't plugged)
I would drop the bowl and give it a good look.
Just a small piece of grit would cause the symptoms your describing.

cheers
Bob
 

rumme

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Jun 11, 2008
Messages
45
if the main jet was blocked, im assuming it wouldnt run at all....or having half choke wouldnt make the engine run good...would it ? In other words, setting the choke on half way makes the engine run decent.....how would that unclog the main jet ? If the jet was clogged, adjusting the choke wouldnt make the engine run better or make it act as though the jet was unclogged...would it ?
 
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