Help please, 138 Lifan won't idle without choke.

[AJ 138cc]

Hi all,

I just assembled my Pitpro 138cc, chucked some fuel in and kicked it over and it started with the choke on no worries. I let it run for a bit while i went around and checked a few things, looking for leaks etc.
Anyway, i flicked the choke off and it died. Tried to start and would not start. Choke on and it starts. I grab the throttle and gently increase idle and flick off the choke and down it goes again. I repeated this several times and then played with the idle/mixture screw. Eventually i could turn off the choke and the bike would idle extremely low and as soon as i touched the throttle it would die. The bike is well and truly hot enough to run with out choke.
Bike will not start at all with out choke in up position.
Any newbie advise people???
Cheers AJ.

 

[mjc85]

You may need to make adjustments to the needle level, move the circlip down a notch or 2 to make it richer and that should fix it.

 

[Mack]

Could have a blocked jet. New tanks have been known to have floatie bits in them. Other than that do as mjc85 said.

 

[Postie]

When you turn the choke off you could be putting it on.
Or are the butterfly looking bits inside the carby 180 deg out?
Not sure if it's possible but I know my postie dies if I put the choke on after it has warmed up...
Quicker to check than the above.
Remember K.I.S.S (Keep It Simple Stupid)

 

[mjc85]

Hey postie the 26mm mikuni as on the pitpro don't have a butterfly choke, but yeah choke on is lever up, so you definately have the choke lever up and it runs ? Does it idle high?

Before adjusting the needle try what mack suggested, open the carby and remove the jets and give them a blow out with a compressor, if that doesn't solve the problem then maybe your idle level is too low?

When the bike is running with the choke on, give it a bit of throttle then turn the choke off, does it keep running whilst giving it throttle? Your idle is possibly too low.

If these don't fix it then it must be your needle adjustment.

 

[AJ 138cc]

Tried all that except for needle position. Will do that tomorrow when i get back home. I will be sure to post my results.
I did manage to get it to idle with no choke but even the slightest bit of throttle and she would die.
Yes it does idle high with choke on. Its almost like its flooding or something. Is there a float level in the carb? Silly question. Could that be not floating due to rough transport?

 

[tubes380]

ive got the problem with my pitpro every time you crack the throttle open it coughs and dies the bike idles fine and runs fine otherwise its only when you give the throttle a good turn from idle that it plays up tries moving the needle clip down to the very lowest clip (came on 2nd lowest) but that didnt help anybody else got the same problem

 

[mjc85]

Try starting the bike with CHOKE OFF, after a few trys, remove spark plug and report back with results. Should be either really black or a ceramic/bone colour

 

[AJ 138cc]

Um so? How do i adjust the needle position? Pull the slide out i guess? Going to take a closer look now.

 

[mjc85]

Pull the slide out, compress the spring to remove the cable from the slide, then take the spring out of the slide and turn upside down and slide should drop out. Now remove circlip carefully and move it down a notch towards the pointy end of the needle, replace and retry.

 

[AJ 138cc]

Ok, tired that. No success. Ive been on the phone to a mechanic who knows a bit about the 25mm carb and he told me to pull it off, including the manifold. Underneath the carb is a mixture screw. Turn all the way in and then anti clockwise back 2 full turns. That should be standard A/F mix.
Did that too. No luck.
The bike is under warranty so im getting a new carby sent up. It should be here early next week. I will keep you all posted incase any of you are having a simmilar prob. If i get a chance i will completely re build the carby i have and clean jets etc. If it works i might end up with a spare carby.
Cheers.

 

[mjc85]

The carby that was on my Orion was a dud and a 26mm mikuni too, had a problem with the casting resulting in it breaking up above about 4000rpm

 

[johnnie5]

i put $50 on a blocked pilot jet

 

[AJ 138cc]

Your on. Im thinking it could be the prob too. Idle's fine but dies at any amount of throttle.. Even though im getting a new carby, i will pull the whole thing appart tomorrow and inspect everything. Clean and re assemble. And try it again. If it works i will have a new carby as a spare.
... im not paying you $50 if your right either. Just for the record.

 

[Mack]

Blocked main jet would be where I'd put my money

 

[mjc85]

Make sure you blow the jets out with an air compressor.

 

[AJ 138cc]

gave the jets a ******** and fixed the problem. Bike is hammering.
For a little 138cc anyway. Big step down from a CR250. but i love every miniute of it. Thanks for all your help guys.
AJ.

 

[Mack]

Don't ya love it when its an easy fix.