66cc bike engine bogging bad!!!!

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fall_down_stand_up

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Apr 26, 2009
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granbury
At low rpm's it boggs and when I can finally get it up to around 20 mph it will kick in but act like its is cutting in and out at times or running out of gas or something....I changed the fuel filter and changes the cdi with one I had laying around and still have the same problem....I also built a new intake gasket and still the same problem....What gives?:-||
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Los Angeles, CA.
My first guess is that its running too rich, but lets wait until your engine is broken in before messing with the carb...
Check your spark plug gap & make sure your gas is mixed @ 24:1 for the first 2 gallons; and remember to shake it well before pouring it into the tank.
Also... make sure the choke lever is DOWN while riding.
 

fall_down_stand_up

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Apr 26, 2009
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granbury
Gas mixture is good and I have been using this engine for 800 to a 1000 miles....I bought a new carb for it a few months back,took it off to and cleaned it....Still had the same problem so I took a old carb I had laying around and cleaned it and put it on and still the same problem....Im dumbfounded....Could it be shorting out going to the magneto?The plug is only a couple months old so I dont think that is the problem eather.....
John
 

Spunout

MB Builder Extraordinaire
Jul 21, 2008
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coventry, RI
blog.360.yahoo.com
sounds to me like its sucking air in from someplace. i suggest spraying carb cleaner or something around where the carb and intake meet, the intake/jug, around the head, and at the base where the jug and bottom meet. the revs will either go up or down at the site of the leak, if there is one
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,271
1,810
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Los Angeles, CA.
dont assume the plug is fine... take it out & check it... I had a new plug 2 weeks ago go bad, the electrode came loose & was touching the ground.
Check all the wires... maybe they are getting hot & grounding out?

you say you have a second carb? take the jet from that, solder it closed & redrill it a size smaller... put it in your bike & see what that does?
 
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fall_down_stand_up

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Apr 26, 2009
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granbury
dont assume the plug is fine... take it out & check it... I had a new plug 2 weeks ago go bad, the electrode came loose & was touching the ground.
Check all the wires... maybe they are getting hot & grounding out?

you say you have a second carb? take the jet from that, solder it closed & redrill it a size smaller... put it in your bike & see what that does?
Ok just got back from a slow boogy ride....I took the magnet out,cleaned it,reziptied the wires to the frame and checked for cracks in wires....Cleaned the plug,but it looks like it is bearning perfectly clean with tells me its getting good spark and the oil mixture is ok....I think the next step is to take the carb back of and change the needle and set(jet)....I tried drilling the jet out on a old carb in the past but had no luck so I sodered it closed and went back to the same size....Im pulling my hair out here....Man I wish there was a bunch of us that lived in the same area so we could start a motor bike club and get togeather and help eachother out with our bike problems from time to time....Vinice I will go get another plug from autozone to make sure....Thanks for all the help guys keep sending any other ideas....Oh the compression is great so I know its not a weak motor and it will also come alive from time to time...
John
 

Retmachinist

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Oct 21, 2008
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Urbandale Ia
Are you using the spark plug, and the little fuel shut off valve that came with the kit? If you are I would throw away the spark plug and go buy an NGK B5HS. Gap it at .035.
Then watch the gas flow to your fuel filter. I had trouble with some of the kit fuel valves starving the engine for fuel. I threw them away and put on a small ball valve that they use on B&S small engines. I would give those two things a shot. It will only cost your around $5 total.

John
 

fall_down_stand_up

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Apr 26, 2009
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granbury
Are you using the spark plug, and the little fuel shut off valve that came with the kit? If you are I would throw away the spark plug and go buy an NGK B5HS. Gap it at .035.
Then watch the gas flow to your fuel filter. I had trouble with some of the kit fuel valves starving the engine for fuel. I threw them away and put on a small ball valve that they use on B&S small engines. I would give those two things a shot. It will only cost your around $5 total.

John
I have ran that idea of the valve on the gastank starving the motor but never changed it....I took the valve off and took it apart lastweek and checked it for flow and it seemed to be fine....I will go down to the lawnmower shop and get a ball valve tomorrow....I did put another jet on the carb that hasent been sodered on....I will also pick up the sparkplug you mentioned....
 
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fall_down_stand_up

New Member
Apr 26, 2009
554
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granbury
Are you using the spark plug, and the little fuel shut off valve that came with the kit? If you are I would throw away the spark plug and go buy an NGK B5HS. Gap it at .035.
Then watch the gas flow to your fuel filter. I had trouble with some of the kit fuel valves starving the engine for fuel. I threw them away and put on a small ball valve that they use on B&S small engines. I would give those two things a shot. It will only cost your around $5 total.

John
Retmachinist I went down and bought a briggs gas shut off valve,but all they had was a plastic one..........It is the right size 1/8 inch with tapered threads.....Is this plastic valve worth trying?it looks kinda cheap and im afraid it will break threading it in or leak....It is black with a red shut off valve....Is this the right one you use?It cost 8.85,kinda high for a cheap peice of plastic....
John
 

noobtard

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Apr 25, 2009
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PA
I'd be pointing at the spark plug.. mine ran fine for a couple weeks with the stock.. and then I started getting "violent stuttering".. plug was to blame..
 

fall_down_stand_up

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Apr 26, 2009
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granbury
I'd be pointing at the spark plug.. mine ran fine for a couple weeks with the stock.. and then I started getting "violent stuttering".. plug was to blame..
I changed the plug,cdi,magneto and drilled the fuel valve out to get a straight flow(have a few extras laying around)to see if it was fuel problem and nothing has helped....The only thing left is the carb....I ordered 2 and they should be in monday or tuesday....
 

Nopedaling

New Member
Jul 11, 2014
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Atlanta Ga
I hate to bump a thread so old but I'm having the same issue with it cutting out at around 30 wot and bogs low rpm. Did you ever get the issue resolved?