Need help tuning Lifan 140

[locko90]

ok ill give that ago mate thanks. oh and the eclip is on the bottom notch atm that's where it was when I got it off a 125cc engine.

ill try raising it

 

[locko90]

Well i just went out and quickly took the carb off and took some pics.

does the float tab look about right?

I left that the same and raised the e clip one notch from the bottom.

It seemed to run worse with the e clip one notch higher.

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[my67xr]

The standard setting on the needle clip is on the centre notch

Carby look's pretty dirty inside, that gum/scale on the float can come off and block the jet's
Float arm look's twisted between the 2x float's, are the float's sitting square to each other ?

The mixture screw look's like it's less than 2x turn's out but it could be the picture too.

 

[locko90]

Yeah float arm is a bit twisted but its square.
And thats it right on 2 turns out from seated.

Yeah its pretty dirty i have cleaned it out few times with throttle body cleaner.

Ill have another go at it tomorrow hopefully i can get it right.

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[locko90]

Well ive been ****ing with this thing for about 8 months and im still not able to get it right so i just bought a 28mm molkt carb off ebay. Hopefully ill be able to get that right.
Nothing stresses me out more then this piece of ****! Ffs
****ing around with different clip heights mixture screw float heights different air filters different jets.grr im so stressed over this ****!

 

[locko90]

Sorry about my last post just making me furious.

 

[locko90]

I actually had the bike running pretty good vety close to perfect when i put a air filter on with no air filter oil on it, cuz it was a bit rich with the well oiled air filter on it. I thought i would try and lean the mixture with more air intake and it was better! But i thought it was still a tad rich. So i took the carb off and raised the float tab to lower the fuel bowl level then it ran like crap! Dying at about quater throttle.
Then i put the float tab back down i did a heap more ****!
Anyway... with this new carb. Are they any good??
I belive its got an air screw on the side ?? Not sure but i think the mixture screw is on the side and not under it so should make life a little bit easyer.
Not sure what jets they have. Should i need different ones ?

 

[my67xr]

Sometimes if they been left sitting for a while they get dried up gum etc holes block up etc.
They are cheap to replace and just start fresh.
I prefer them over the Molkt.

With the Molkt just check the float doesnt rub on the insides of the float bowl and on the main jet tower on the body of the carby.
The Molkts can be a bit hit and miss so if you cant get it running easily let the seller know and they might send you a new one .

 

[locko90]

yeah well i hope she goes all good. Thats probably what it is i havnt had the carby blown out with a air compressor. Anyway just guna start fresh with a new carb. Im over tryin to get it going.

 

[locko90]

I got the inlet manifold off the other day, and I noticed that there was a patch of fuel on the head end gasket. would this mean there was a air leak there ?

I ordered new gaskets cuz I stuffed the other one taking the manifold off anyway. oh well im kinda thinking this is what was causing my engine to backfire at higher rpm.

 

[locko90]

hahah got the new gaskets on today and still had the same problem! so I got some break cleaner and sprayed it around the carb intake and sure enough the engine dies. did it around the cyclinder base, yep engine rpm slows down. heres my problem! not the carb but a leak in the inlet manifold.

I remember you telling me to spray wd40 around the intake at the start of the thread but I didn't have any wd 40 so I skiped that fml. didn't know I could use break cleaner

any way im going to try a different inlet manifold off a 125 engine I got and see if that ones leaking aswell.

 

[my67xr]

You can use anything wet to find a vacuum leak.

With the manifold mounting face being warped you can sand it flat if you are careful.
Use some 320 wet and dry paper on a hard sanding block, mount the manifold in a vice, clamped in with a rag.
Only move the sandpaper wrapped block back and forth about 20mm, so there is less chance of sanding a half moon shape into it (sanding off too much around the bolt holes)
Watch the surface of the manifold after sanding it a couple of time's, you will see the sandpaper leave's mark's on the outside around the mounting bolt's, and might not mark the centre section around the port.
sand it flat till it is all the same.
For the gasket you could use a bit of cardboard from a cereal box and cut it out to suit the manifold if you need to.

There are some pic's of how to do it in this thread (show's how to sand carby face, but same principle) -
http://www.miniriders.com/chinese-mini-s/41585-help-needed-extreme-bogging-terrible-performance.html

 

[locko90]

I changed a different manifold from the other engine I had (that engine ran fine) and put it on to this one, managed to seal the air leak on the carb end of the manifold, but the cylinder end still has the air leak and that's got a new gasket aswell.

Tried to use a cereal box cut out to add extra width to the gasket already on there, thinking it might help seal that cylinder up and it didn't do much still had the leak.

I have run a razor blade over both inlet manifolds to get old gaskets off and they both seem very flat, could it be the cylinder is warped ?

well im going to head to bunnings to get some 320 grit sandpaper and ill give that a go cheers mate.

 

[locko90]

or should I just keep adding cereal box gaskets to it ?? >>

lol seal that leak up like a boss

 

[locko90]

Got it looking better. Does it look ok ?
I used 600 grit cuz they didnt have 320
Either 600 or 180. So got the finer stuff.

Dont have a vice so just used my hand and a cork sanding block.

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[locko90]

The head looked a little rough so i gave it polish aswell

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[my67xr]

Give it a try now with the surface's flat.
Did you put a rag in the intake port when you sanded the head so the alloy filing didn't go into the engine?
Might be able to vacuum it out, hopefully the inlet valve wasn't open.

 

[locko90]

New gasket

All back together just gota wait till tomorrow before i can start it

Im so hoping this seals it!!!!

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[locko90]

yeah I had a bit of plastic bag jammed in there man. blew it all out off before I removed the plug too

I gave it a kick in the guts this morning started right up, sprayed brake cleaner around that area, annnnd still there!!!!!! had such high hopes it would be gone, just my luck

there's something else I've noticed, could there be a leak where the head bolts on to the cylinder?? cuz if I spray brake cleaner in the gap between the air fins it stalls aswell, or it just could be that its going in the manifold leak anyway, not sure, think it could be leaking there?

**** I was so hoping this would work~!!!!!!!

 

[locko90]

Right here looks like theres still a gap.

Going to take it off and give it another sanding.

Might chuck some more cereal boxes in there aswell

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