First build: no idle, no power, no throttle

LWalker

New Member
Joined
Apr 19, 2020
Messages
5
Hi everyone,

I am BEYOND frustrated with my motorized bike. I finished assembling my bike yesterday and it starts - but just barely. I peddle up to about 5-10 mph and release the clutch to engage the motor. The motor engages but there is absolutely no power whatsoever. There is also no idle - the engine is so weak as soon as I stop pedaling, the motor completely dies. I was able to get the bike to idle by turning the idle screw all the way in - however, when I did this the engine was idling way too high. Lastly, when I twist the throttle I can hear something in the carb being raised and lowered but the throttle has no effect on the engine whatsoever. I get 0 acceleration from the throttle and I can't even hear it making the engine rev.

I suspect these are all symptoms of one core issue but I'm not sure what that issue is other than it probably has something to do with the carb. Does anyone have any suggestions? I don't want to take the bike to a mechanic (do mechanics even work on motorized bikes?) but I really need my bike working so I can get around.

Here are some of the specifications of my bike.

29 in Mongoose Excursion.
Zeda Firestorm yd100 kit (so yd100 engine)
Extra Long Carb offset (I couldn't get the carb to fit under the frame)

This is the carburetor:

https://www.bikeberry.com/2-stroke-speed-carburetor.html?keyword=&utm_source=google&utm_medium=cpc&gclid=CjwKCAjwwYP2BRBGEiwAkoBpAm6Slw10yzOUH1xbvgq_GnPuDPgm6PtNEBmlcuVm1-AfwH65Ye_gZhoCOVgQAvD_BwE

One other thing to note: My spark plug is a little loose in the engine - I had to hand tighten it because none of my wrenches fit around the plug. A bit of gas was leaking from around the plug. Could this be the cause of all my issues?

Please help!
 


Wrench

Well-Known Member
Joined
Nov 14, 2018
Messages
1,386
One other thing to note: My spark plug is a little loose in the engine - I had to hand tighten it because none of my wrenches fit around the plug. A bit of gas was leaking from around the plug. Could this be the cause of all my issues?
Yes - Must tighten the spark plug more than hand tight
 

LWalker

New Member
Joined
Apr 19, 2020
Messages
5
Yes - Must tighten the spark plug more than hand tight
Ok, I will do that tomorrow. I also just noticed that there was a lot of oil and gas leaking from my cylinder head - I will put a good gasket sealant on it. Hopefully all my issues boil down to compression problems
 

Tyler6357

Well-Known Member
Joined
Sep 28, 2011
Messages
1,112
Ok, I will do that tomorrow. I also just noticed that there was a lot of oil and gas leaking from my cylinder head - I will put a good gasket sealant on it. Hopefully all my issues boil down to compression problems
I wouldn't put a sealant on it. How tight do you have your head bolts? They should be tightened to 12-15 foot pounds of torque. If oil is coming out from the head gasket you must have a leak that is causing compression problems. If it won't seal at the recommended torque levels, replace head gasket and also check your head to make sure it's flat and not warped, I've seen warped one from the factory before.
 

LWalker

New Member
Joined
Apr 19, 2020
Messages
5
I wouldn't put a sealant on it. How tight do you have your head bolts? They should be tightened to 12-15 foot pounds of torque. If oil is coming out from the head gasket you must have a leak that is causing compression problems. If it won't seal at the recommended torque levels, replace head gasket and also check your head to make sure it's flat and not warped, I've seen warped one from the factory before.
Hey Tyler,

Thanks for responding! Why don't you recommend sealant? I liked the idea of sealant because I have no way of measuring how tight the nuts are. I don't have a torque wrench only a socket wrench. I tightened them down until it was difficult to turn the wrench any more.
 

Tyler6357

Well-Known Member
Joined
Sep 28, 2011
Messages
1,112
Hey Tyler,

Thanks for responding! Why don't you recommend sealant? I liked the idea of sealant because I have no way of measuring how tight the nuts are. I don't have a torque wrench only a socket wrench. I tightened them down until it was difficult to turn the wrench any more.
It's just not practical to use on these heads, it will probably make it less flat and create an even bigger leak. A flat cylinder and a flat head need to be sealed with a head gasket.
 
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