Jing ke carb

[chrisorion]

Hey

I am wondering weather anyone can shed some light on the situation i am having with my 125cc orion pit bike with a ducar engine. with a jing ke carb now i believe i may be having some issues with the carb.

As i know bikes take time to warm up thoroughly and for them to idle properly.
Although my bike takes abnormally long as in atleast 2 mins not 30 seconds like my mates, even though i can feel the engine warming it still refuses to idle for me...

No the bike runs perfectly doesnt miss a beat starts easy 2nd kick with choke on and half throttle, then quickly switch to no choke... this is also to say once the bike is hot it will hold its idle just fine...

does anyone know why this could be? any advice would be appreciated

 

[sean01]

could be a lot of things..

has it always been like this?

pretty sure the carb you have is a 19mm carb, bit on the small side and probly far from being jetted good enough...
china like to use this carb on a lot of different sized engines and not changing anything in them...

apart from that do a major service, making sure the air cleaner is in good condition and oiled up nicely..
then retune or replace the carb with a decent sized one like a china 26mm or pe24

 

[chrisorion]

i bought this bike second hand and have got it too this current state, extremely better then the previous owner had it.

when it comes to the servicing of the bike i have done the basics... i did a complete tear down of the carb and cleaned it all out, adjusting the main needle... and air filter is a unifilter all clean and oiled up, new fuel filter new oil etc...

i was hoping there may be something i was missing that could be causing it not to idle when warm, cause its a bugger when you got to wait for it to get hot hoping someone else had the problem as well and had way of fixing it..

if you have anything i could try i would greatly appreciate it

 

[sean01]

only thing to try is adjusting the mixture screw and making sure the valve clearance is good..
checking that the carb is sealing good would hurt too..

new gap if ya havent already

 

[chrisorion]

ok well i have done all that... so if i was to work up the courage to adjust the valve clearances what should i set them to on this bike... ooracing say 4 intake 6 exhaust... what would you recommend...

plus i cant find anywhere that explains what incorrect valve clearances affect on the bike, hopefully someone can answer this

thanks

 

[sean01]

.003tho on inlet and .004 on exhaust mate..

bad clearance on the inlet can cause compression to force some of the intake charge back to the carb..so basically the engine will starve..
on the exhaust it can cause the valve to burn out.. exhaust valve clearance on these engines never really move so if your unsure just do the inlet but if your brave enough lol try and do both..
engine will run hotter than usual as well..

oh and i forgot to mention earlier..

make sure your operating your choke the correct way too.. sounds dumb but plenty do it back to front lol

 

[chrisorion]

nah i will do them both probably on Thursday and see if that makes a difference and see if there actually out...

haha yea i an imaging i was curious at the three positions it had at first till i looked at the butterfly positions in the carb, but good thought!

i really appreciate your help and advice on my issue!!

if you dont mind me asking and taking your time, what is the go with the oil filter screen should i also do that i know it involves taking the right hand side of the engine off and cutting back some of the gasket but is it worth doing or? and is there any good tutorials on this...

 

[chrisorion]

well i did the valve clearances today and it has fixed the issue completely so i am over the moon with your help... although its caused another issue that when i go quick to full on the throttle to rev it it dies... when i give it a small amount of revs then throttle it is 100% good.. i am guessing this is a tuning issue on my carb would anyone agree ??