Carburator coffing and splattering!!!

[swyer]

hey guys can anyone help me?

I have a lifan 140cc with a mikuni 26mm carbi, im struggling with setting up the bike so it idles without coffing and splattering and eventually cutting out.
i have already

-Cleaned the carbi
-adjusted the air/fuel screw 2.5 turns out
-fiddled with the idle screw and the only way the bike will run is through having the idle turn up really high!

the bike is about a yr old and suddenly started doing what it is!

note: bike seems to idle fine when the choke is on but when i go to ride it, the bike bogs down and i have to keep the revs up for it to run, but then it also seems to splatter when im just cruising along at a steady pace also i have noticed it backfires a lot more on engine braking!

any help will be appreciated!!! thanks

 

[user 11561]

!

Have you tried cleaning the airfilter? Alternative just try taking it of to see how much a difference it makes!

 

[swyer]

yeah

Yeah, done that all when i done the carbi clean!

 

[Undicided]

Get a new Jet that fixed mine

 

[zumanity]

mate my lifan 125 has started doing the same thing. while i dont have an answer for you i will be watching this topic with interest!
Did u actually pull the carby completely apart or just give it a spray with carby cleaner?

 

[headsmess]

check the valve clearances if its been a year of usage...

is the mikuni the prick carbs with the mix screw at the bottom, not the side?

go track down a model helicopter tail rotor with shaft drive...they got a nice lil right angle drive thats ideal for adjusting the screw...and a LOT cheaper than the real thing from a bike/tool shop(can even make one from lego if your really keen)

if its on the side ignore that tip...but check the valves anyway

 

[swyer]

!

yeah pulled the carbi apart and cleaned jets out and blew compressed air through them and made sure they were clean... yeah ill see if i can borrow a mates jet n see if theres any difference

 

[bulldog93]

this happens to my XR200R(ts125 motor in it) it's been doing it for ages when i brought it, it was doing it so just keep the revs up, has no air fillter, haven't cleaned the carbi and now i can't kick the bloody thing over, my fualt i gusse but for $300 i gusse it was going to be shit.

bit off topic but though i would put that in but i got no help for you, hope you get it sorted.

 

[Kraycer]

i got the same problem mate, done the exact same thing to try fix it as u as well!

hopefully someone out there has a answer to dis.

 

[Fiddy@norway]

tried to install a different size pilot jet? sounds like your lean or way rich, does it start easy? does it run good on wide-open throttle?

 

[swyer]

!

thanks guys keep all the tips coming, they are useful to know.

yeah im going to try the valve clearances this weekend and see what they are like.

And yes mikuni carbi is the prick carbi that does have the air/fuel screw on the bottom of it and at the moment i have to un-bolt the carbi to adjust it! (very frustrating)

 

[bulldog93]

just get a new carbi, all prob solved.

 

[crazy-latin-steven]

i was looking at those Molkt carbs are they anygood?

 

[bulldog93]

you know what, is the fuel tap turned on???? or your lines could be kinked

just putting it out there.

 

[swyer]

nah mate im not 100% convinced its the carbi that the problem has originated from. i want to check everything before i go out and waste money on a new carbi, and yeah fuel and the lines all run freely

 

[headsmess]

someone metioned valve clearance, its an idea to whip out the feelers and check em, only takes a few minutes...and if thats ok, id be checking out a new cdi n crap. dont bother with the overpriced race ones, they dont do much but then theyre only 30 bucks as compared to a genuine honda one of 300 bucks....

quick test...when its warm and does its thing, check the spark then...

 

[zumanity]

i pulled my carby off today and noticed that the spacer between the carby and manifold has a piece broken away.....not enough to pass the round seal but who knows when its under load???
just a thought to contribute.

 

[twisties]

did you say it runs better with the choke on?

that means you need to turn your air/fuel screw to make it run richer. what way you turn it depends on the carb, might have to look that up on google.

i see you said you turned the air fuel screw 2.5 turns out - thats only meant to be a rough reference as to where the sweet spot is, not necesarily THE sweet spot. keep turning it in/out until your bike is running sweet.

hope that helps

 

[swyer]

yeah good thanks guys, still havnt had the chance yet to try most of these tips but i certainly will this weekend, just another quik question... What size feeler gauges should i use to check the valve clearances?

 

[headsmess]

standardly .004/.005 or two sheets of paper i think? them damned feeler guages are expensive i, errrr, borrowed mine