can't find an answer then ask here someone may be able to help!!

[maniac57]

Try swapping the jets and needle from the original carb. The size of the chinese jets can be WAY off the size marked...
Every single ht I've built was blubbery rich from the factory, but I can usually get them running okay without a jet change. I like my engines to run clean under load and four-stroke a bit the rest of the time since they last MUCH longer a tiny bit rich.
Jetting for max power is a chancy thing with the "quality control" the chinese practice.
As far as gas spitting back through the carb, this is totally normal with a non-reed piston port motor. You just see it better without a filter.

 

[Shays]

"quality control" or complete lack there of..Nice..couldnt be more true.....Ill give it a shot, thanks

 

[dsword75]

Howdy, been dealing with some slight four stroking lately and low power on steep hills. Mind you, they are pretty steep hills. But today I adjusted my float by ever so slightly bending them to toward the top of the carb, in order to allow more gas in the bowl. Now today, at right about full throttle, the choke turns itself on. Right now I got a rubberband on the choke lever to hold it down for a quick fix cuz I was on the road, but am I correct in assuming my tinkering is the cause of this? Also, for the last week or so I have been trying to adjust my idle (stock NT carb) and I swear I can screw the idle adjustment screw all the way in or out and you will not notice any difference in idle on a warm engine. Any advice? Greatful. -Dan

 

[GratefulUndead]

Hi I'm new to the forum and really need some help! I just got finished buildingmy second bike put fuel in it, go to start, and clutch doesn't catch to get it started. It's as if the clutch is disengaged whether the lever is stressed or released. I tried adjusting the clutch but not sure if I'm doing it correctly. Can someone please help me?

 

[maniac57]

Howdy, been dealing with some slight four stroking lately and low power on steep hills. Mind you, they are pretty steep hills. But today I adjusted my float by ever so slightly bending them to toward the top of the carb, in order to allow more gas in the bowl. Now today, at right about full throttle, the choke turns itself on. Right now I got a rubberband on the choke lever to hold it down for a quick fix cuz I was on the road, but am I correct in assuming my tinkering is the cause of this? Also, for the last week or so I have been trying to adjust my idle (stock NT carb) and I swear I can screw the idle adjustment screw all the way in or out and you will not notice any difference in idle on a warm engine. Any advice? Greatful. -Dan

Look for an air leak in the intake tract.
As far as the choke lever, they can simply get loose under vibration. A rubberband or spring is as good a fix as any. New carbs are cheap if it annoys you.

 

[maniac57]

Hi I'm new to the forum and really need some help! I just got finished buildingmy second bike put fuel in it, go to start, and clutch doesn't catch to get it started. It's as if the clutch is disengaged whether the lever is stressed or released. I tried adjusting the clutch but not sure if I'm doing it correctly. Can someone please help me?

Look at Norms clutch thread in the classic motor bicycle instructions. Search here and find almost ANY problem possible.

 

[Jesse_James]

When I start my bike for the first time for the day (or anytime I have it rest for awhile) it runs fine for the first 5 minutes. Then things get funny. The engine starts losing power and would want to stall. But when I pedal it (as its stalling) and give it throttle a little it goes back to running good for a couple of minutes then the same thing happens why is this? How can it be fixed? I shouldn't have to pedal like this at all unless I am pulling out from a stop sign or red light at idle. I also notice a really high idle when coming to a stop then if I push my bike forward with my feet it goes back to a normal idle.

 

[GearNut]

Sounds like an air leak. It could be at the carburetor to manifold seal, manifold to cylinder gasket or one of the crankshaft seals. The "pushing with your feet" idle speed fix... I have no idea. Just chance timing of the events when they occur?
It also could be a poorly vented fuel cap or some random dirt swimming around in the carburetor float bowl temporarily blocking the fuel jet?
Spark plug acting up?
Many different issues can cause the symptoms your engine has.

 

[chessir]

hi norm,
I need help figuring out how to get back clutch engagement. I started out with clutch engagement in the released position.Then I went to the locked position and messed with the star nut to the point where in both the released and locked position the clutch will not engage. In other words I can turn the nut in either the released or locked position.
How do I get back to having an engaged clutch. Seems no-matter where I turn the star nut I cannot get to clutch engagement like I had before I messed with the star nut.
I have searched the forum but I cannot find instruction for simply getting back clutch engagement.

 

[GearNut]

have you tried reading this thread here?

 

[=StreamlineDeco=]

Hey guys,
New guy here from SoCal. I recently built my motorized bike: Huffy Nel Lusso with a no name brand 66cc 2-stroke from venice motor bikes (wish I knew what model it was). Here's the thing: Earlier while riding I encountered a loss of power, suddenly, I had my hand on the throttle and it was going, then all of a sudden, I started losing power. I tried to give it more gas but it wouldn't come to life. PLEASE, any tips would be appreciated!! I checked all my fuel lines, adjusted the throttle cable some. I have no air leaks. My stock spark plug seems to be working fine. I will get the newer NGKb5hs plug soon. I've read some things about the magnet adjustment for the timing, but how can it be off if I was riding it and it gave out while running? Any info would be appreciated guys. Thanks in advance! Here's a photo of my recent build:

 

[Norman]

check this out http://motorbicycling.com/showthread.php?t=13953
read through it try one thing at a time to trouble shoot your problem.

 

[joker]

Help my 4 stroke gxh50 runs beutiful just before it runs out of gas.
The rest of the time it runs terible won't react when you give it gas but just before it runs out of gas superb.
What am I missing ?

 

[=StreamlineDeco=]

Thanks Norman! I will definitely run through this check-off list to try to solve this issue. I think I will need a new boot and spark plug, too. Earlier, I disassembled it and realized the brass fitting inside was damaged. The slots that are there to keep the small U-shaped clip in were broken. I tried to bend the clip around the brass cap, but it didn't aleviate anything. I'll end up replacing it anyway. Thanks for the tip!

=Adrian=

 

[maniac57]

Help my 4 stroke gxh50 runs beutiful just before it runs out of gas.
The rest of the time it runs terible won't react when you give it gas but just before it runs out of gas superb.
What am I missing ?

If it only runs right as it runs out of fuel, it is running too rich the rest of the time.
Lean out the mixture.

 

[BarelyAWake]

Very likely that's true, but the plug should be examined before & after altering the mix jus' to be on the safe side

gray/white it's lean
coffee/tan it's perfect
black/wet it's rich

http://motorbicycling.com/showthread.php?t=24873

 

[Nunyadam]

what size is the woodruff key for the engine sprocket on a 66cc china girl?
The nut holding the sprocket came loose and the key fell out. the key way is damaged on the 10 tooth sprocket. ("v" shaped now),
I ordered a new sprocket, and can get keys local, I'm just wondering what size it is before i go shopping.

 

[Nunyadam]

bought some straight key bar stock and made my own for now. back on the road for now.
I'll go get the proper key when i get the new sprocket.
for the record it is a 1/8" width key.

 

[HardcoreHadaway]

Hello Norman,

Good on ya helping people out like this, I hope my problem can be solved by your expertise.

I am still breaking in my newly mounted kit and I am losing power. I believe it is a fuel problem. The bike will go seemly fine until it seems to just choke out and slow down then speed back up. I heard about there being a gas cap problem but this still happens with the cap off. I can really feel how it should be running if I turn the gas valve on the tank to off. Then it doesn't seem to stop accelerating... until all the gas is used in the hose and fuel filter.

What do you think??

PS I think I found similar problems here and am replacing the boot and plug, I have only run 50:1 mix.

 

[Jeckler]

It's too rich, or the float is too high. Maybe even a little of both.
What does the plug look like and what's the angle of your carb?