Needle Position for lifan 140

[edzy]

hey guys
ive searched the fourms but cant find the exact answer.

what setting should the needle clip be on?

its currently on the middle setting but its a bit boggy when i hit the throttle.

any ideas?

thanks

 

[numroe]

Mate, no short answer to that. Which is prob why no answers yet. It depends on carb model and size, slow and main jet sizes, air filter condition, humidity, altitude, and air temps.

If you have a Mikuni 24mm, then stock setup works okay at sea level and moderate humidity and about 25C:
Stock: M= #97.5 (41thou), P=17.5, screw = 1.75, needle 1dn (clip up = leaner).

Listen to and feel your engine. Rough = rich, hesitation = lean. Real rich or lean can cause a bog, but a rich bog is usually a cough type bog. Set needle in mid posn. Note throttle position. Snap to wide open, feel then set main jet. Snap to 1/4 open, feel and set slow jet. Then snap to 1/2 open and feel and set needle.

I have my OKO26 ripping on my Lifan 140. Always near sea level. Air temps between 23 and 33 not making a huge diff but humidity does (eg. humidity 50% versus 85% and I change the main jet). Maybe the OKO26 is a fussing thing, not sure since I only played with a Mikuni 24mm for a few rides. I am running:

Slow jet: K38.
Air screw: Approx 1.75 turns out.
Needle: One clip richer than mid (clip down 1 from mid).
Main: K100 or K102 depending on conditions. So quick and easy to change on a OKO/Keihin!
Float level raised substantially. No idea now to measure it though.

I can go full throttle at any time. It always pulls hard from idle out of corners when you are committed and need the power badly. Never misses a beat on jump landings. Maybe under some freak conditions it will bog, but that did not happen yesterday.

 

[edzy]

ok,
well the carbys a mikuni 30mm.
after riding my mate dhz that he has barely ridden
i figured my bike has lost its "get up and go".
so i thought back to when i change my throttle cable when i took the needle out (just to have a look). and i dont think ive put it back in right.

so im just after a standard setting.

 

[themountain]

Very simple answer: If you start messing around with the jets put it always in the middle!! I guess you are a bit lean on the pilot...post your Jetsizes

 

[Cactus Jack]

ok,
well the carbys a mikuni 30mm.
after riding my mate dhz that he has barely ridden
i figured my bike has lost its "get up and go".
so i thought back to when i change my throttle cable when i took the needle out (just to have a look). and i dont think ive put it back in right.

so im just after a standard setting.

I checked two new "25" Mikunis and the clip is in the bottom groove in both ....... when you take the needle out there is a "W" clip that holds it down ...... you have to make sure you put it back in before you put the spring and cable back in ....

Also if your engine 'aint blowing smoke or using oil ...... CHECK that you have adequate valve clearances ..... lack of clearance basically causes compression loss as if the rings have lost their seal and can be a cause of loss of " get up and go" .... this type of scenario is also why proper bed-in when new is necessary ... properly bedded and run in engines that are well maintained actually gain more "get up and go" than they had when they were new !

Your carb is a 26 mm oval bore Mikuni (24 mm slide / 30 mm outlet bore) it's stamped on the top of the carb to manifold flange . The 25/26's are 22 mm carbs and have 22 stamped in the same place ......... Tuning is a methodical mess and play thing ........ change only one thing at a time so you always know where you're at ....... and as you've already found out ....... it pays to write down the stock settings before you go altering things ...