Need help: first build; engine wont start was origionally running

Chloe

New Member
Apr 22, 2019
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So I have set the engine onto the mountain bike have checked the spark plug for spark and I do get spark when tested on the outside case. I can get the engine started when I peddle to 20km/h but it wont idle and The throttle needs to be full throttle. If I start at a lower speed I get compression, but it will not start. So I thought that perhaps it was an issue with the gas. So I turned on the gas and watched it flow evenly out of the line into a gas can. so it wasn't an issue with the filter or the line then I decided to check the carb. So I opened it up and the float level was normal the gasket was in good condition. I then decided to further take it apart and checked the air filter and all the "holes' The gas goes through for a blockage. Then put it back together. I did a few other things But now I am starting to wonder if it is a timing or electrical issue. I am new to small engines and any help is well appreciated, thanks in advanced.
 

Chloe

New Member
Apr 22, 2019
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0
1
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also It used to work then I relised that I put the throttle assembly(on the carb) togther wrong so I fixed it then after that it stopped working. It worked prior to that.
 

Jimmy Bloodmaker

Active Member
Nov 24, 2018
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60
28
midwest
it's not timing. timing is done with the ports hard cut through the cylinder walls. check throttle cable tightness. make sure the barrel of the carb slides with the throttle pull and doesn't get hung up. check for air leaks, heck just seal it all with silicon anyway, just to be sure. check your plug color. make sure carb isn't clogged at the jet, shine light down the jet tube and look. check to make sure the c washer is over the jesus clip ( e clip on the needle tht runs through the slide barrel) and the cable is run in the middle of the spring. even try wiggling the carb while its on the intake. does it move? if so, it's leaking for sure. let me know how tht goes and i can recommend other things if it don't wanna scream to life.
 

fishing_basil

New Member
May 13, 2019
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8
3
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triple check your connectors, i had to re-crimp a few of the wires.

also, my fuel lines split, any good hardware store will have the fuel line.
 

donphantasmo

Member
Oct 3, 2010
372
11
18
Middleburg, FL
First, take off your wires, it may be a wiring issue (a short somewhere) so disconnect your wires from the handlebar. If the bike starts, you can just choke to kill.
Next, make sure that your clutch is correctly set. The bike would not start if the clutch doesn't engage fully. So, make sure with the clutch lever fully out, see if you can peddle it. It should be very hard to pedal, if not, then your clutch needs adjusting.

Next, see if you can spray some WD-40 in your intake directly (take off the filter and spray for .5 of a second. Not, try to pedal hard, let the clutch go, and see if it kinda wants to start. If that's the case, then you have fuel delivery issues (issues with carb, issues with petcock or fuel tank or fuel filter on backwards).

Try these steps and see how you do.
 

Citi-sporter

Active Member
Jun 16, 2014
206
42
28
North Bend, Or,
I'm thinking it's carburetor A lot of these engine come with the steel chromed intake pipe There's a lot of problems with those compared to the aluminum ones mainly some early ones were not cut square.

You need to securely seal the carb to intake joint, the best way to do this is to buy a 3mm diameter cross section Viton O-ring in 16mm O.D. and install it inside the carb's clamping recess. It's the best permanent solution. When tightening the carb's clamp bolt press the carb firmly forward so the O-ring get's trapped and squished a little between the intake and carb.

Secondly, have you gone through your carb's float tang adjustment so the float height is about 21~22 mm from the carb's, floatbowl's, mount's upper face? It's easy enough to check, and there should be a sticky here in the forum on setting up your carb before running your engine for the first time.
 
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