Help with a chinese 50cc scooter

martinwest · 23rd February 2016, 12:47

Hi everyone I need some help with a running problem on a scooter I have got for my son when he turns 16 in May its a wangye ghost WY50 QT-16A 2008 two stroke ( yes I know Chinese cr**) but he only needs it for a year. I cannot get it to run on full throttle its ok to about ¾ throttle. The things I have done so far are as follows:-
drained fuel tank
checked fuel vac tap
checked fuel flow
washed foam air filter
checked reed valves
new spark plug
compression test 175psi
replaced carb with new one
replaced coil with new one
checked stator volts and ohms both ok
checked resistance to coil and ignition/ rev counter
tested volts at coil when running and cutting out ( no change)
checked auto choke is working
checked air gap on the trigger and ohms

The only other thing that seems strange is although the rev counter has both power and coil feed it has only worked once and when it did the bike revved on full throttle perhaps a coincidence the bike is not worth enough to get a garage to look at it so any help / advice would really grateful as I don't want to keep throwing money at it.

Mr Bone · 23rd February 2016, 15:47

Its not getting it to run on full throttle I'd be worried about on a Chinese scoot, the quality of the running gear (brake linkages, headstock & swingarm bearings /welding) would be my focus.

Or....

clf · 23rd February 2016, 15:57

Quote:

Originally Posted by martinwest

Hi everyone I need some help with a running problem on a scooter I have got for my son when he turns 16 in May its a wangye ghost WY50 QT-16A 2008 two stroke ( yes I know Chinese cr**) but he only needs it for a year. I cannot get it to run on full throttle its ok to about ¾ throttle. The things I have done so far are as follows:-
drained fuel tank
checked fuel vac tap
checked fuel flow
washed foam air filter
checked reed valves
new spark plug
compression test 175psi
replaced carb with new one
replaced coil with new one
checked stator volts and ohms both ok
checked resistance to coil and ignition/ rev counter
tested volts at coil when running and cutting out ( no change)
checked auto choke is working
checked air gap on the trigger and ohms

The only other thing that seems strange is although the rev counter has both power and coil feed it has only worked once and when it did the bike revved on full throttle perhaps a coincidence the bike is not worth enough to get a garage to look at it so any help / advice would really grateful as I don't want to keep throwing money at it.

I don't know anything about these, however, does the grip rotate enough to give full throttle, or is the cable restricted? Sometimes the simple things are overlooked?

dattrike · 23rd February 2016, 16:03

Check the float level in the carb, it can be critical.

martinwest · 23rd February 2016, 16:05

Yea seen the petrol and matches on nearly every scooter forum brakes and every thing else will get checked when it is running and it has to go for a MOT anyway it is just to get him to work so I don't have to take and pick him up.

As far as the throttle goes it opens fully the problem is it stalls after 3/4 throttle as soon as you let it off it runs again the carb has fuel in it I have let it stall and checked how much was in the bowl

clf · 23rd February 2016, 16:09

Quote:

Originally Posted by martinwest

Yea seen the petrol and matches on nearly every scooter forum brakes and every thing else will get checked when it is running and it has to go for a MOT anyway it is just to get him to work so I don't have to take and pick him up.

As far as the throttle goes it opens fully the problem is it stalls after 3/4 throttle as soon as you let it off it runs again the carb has fuel in it I have let it stall and checked how much was in the bowl

Perhaps not enough air, or when drawing air at max throttle, something collapses like an air intake? Or over 3/4 throttle, does it start to pull the choke cable?

martinwest · 23rd February 2016, 16:18

Quote:

Originally Posted by clf

Perhaps not enough air, or when drawing air at max throttle, something collapses like an air intake? Or over 3/4 throttle, does it start to pull the choke cable?

def not a collapse or air leak I have checked the intake and re-sealed gaskets etc the choke is a different matter its auto choke but again I have checked that.
I wish I could afford a old 1970's jap bike for him at least I could fix it with my eyes closed

Elliott · 23rd February 2016, 16:30

Coked up blocked exhaust, expansion pipe, Or some of the baffles blocking the pipe?

Hairline crack on reed valve where it clamps on?

Engine earth, poor connection to coil (weak spark)

Does it sound like its running out of fuel or more like it hits a rev limit every time?

Sprinter · 23rd February 2016, 16:35

did it run with the old carb?

Just asking because the needles might be at a different height. Try raising it by one notch and see if it makes a difference.

martinwest · 23rd February 2016, 16:38

Quote:

Originally Posted by Elliott

Coked up blocked exhaust, expansion pipe, Or some of the baffles blocking the pipe?

Hairline crack on reed valve where it clamps on?

Engine earth, poor connection to coil (weak spark)

Does it sound like its running out of fuel or more like it hits a rev limit every time?

I haven't had the exhaust off good idea, the spark looks weak but all the voltages are ok and the battery earth goes straight to the coil and as I have never had a restricted bike I don't know but as soon as you back the throttle off below 3/4 it runs fine The reed valve I have checked but I will try putting grease around it and see what happens
Thanks

23rd February 2016, 12:47	#1
martinwest Regular poster MG ZT + Join Date: Jul 2009 Location: Bedfordshire Posts: 88 Thanks: 10 Thanked 12 Times in 6 Posts	Help with a chinese 50cc scooter Hi everyone I need some help with a running problem on a scooter I have got for my son when he turns 16 in May its a wangye ghost WY50 QT-16A 2008 two stroke ( yes I know Chinese cr**) but he only needs it for a year. I cannot get it to run on full throttle its ok to about ¾ throttle. The things I have done so far are as follows:- drained fuel tank checked fuel vac tap checked fuel flow washed foam air filter checked reed valves new spark plug compression test 175psi replaced carb with new one replaced coil with new one checked stator volts and ohms both ok checked resistance to coil and ignition/ rev counter tested volts at coil when running and cutting out ( no change) checked auto choke is working checked air gap on the trigger and ohms The only other thing that seems strange is although the rev counter has both power and coil feed it has only worked once and when it did the bike revved on full throttle perhaps a coincidence the bike is not worth enough to get a garage to look at it so any help / advice would really grateful as I don't want to keep throwing money at it. __________________ [SIGPIC][/SIGPIC]

23rd February 2016, 16:03	#4
dattrike Posted a thing or two V6 2ltr auto in copperleaf +CDTI Auto in Royal Blue on loan to Son Join Date: Jul 2010 Location: Tewkesbury, Gloucestershire Posts: 1,710 Thanks: 105 Thanked 476 Times in 267 Posts	Check the float level in the carb, it can be critical. __________________

23rd February 2016, 16:05	#5
martinwest Regular poster MG ZT + Join Date: Jul 2009 Location: Bedfordshire Posts: 88 Thanks: 10 Thanked 12 Times in 6 Posts	Yea seen the petrol and matches on nearly every scooter forum brakes and every thing else will get checked when it is running and it has to go for a MOT anyway it is just to get him to work so I don't have to take and pick him up. As far as the throttle goes it opens fully the problem is it stalls after 3/4 throttle as soon as you let it off it runs again the carb has fuel in it I have let it stall and checked how much was in the bowl __________________ [SIGPIC][/SIGPIC]

23rd February 2016, 16:35	#9
Sprinter Posted a thing or two Jag S-Type 4.2 V8 Join Date: Apr 2011 Location: Derby Posts: 1,645 Thanks: 271 Thanked 427 Times in 293 Posts	did it run with the old carb? Just asking because the needles might be at a different height. Try raising it by one notch and see if it makes a difference. __________________ “Time flies like an arrow. Fruit flies like a banana.”

23rd February 2016, 16:30	#8
Elliott Loves to post Rover 75 Tourer Join Date: Nov 2015 Location: Sheerness Posts: 261 Thanks: 174 Thanked 61 Times in 50 Posts	Coked up blocked exhaust, expansion pipe, Or some of the baffles blocking the pipe? Hairline crack on reed valve where it clamps on? Engine earth, poor connection to coil (weak spark) Does it sound like its running out of fuel or more like it hits a rev limit every time?