Carb problems on my new 250

Cheryl · 04-04-2008, 11:45 PM

I just got a new LF250. It came in a box. After assembling it, I had a hard time getting the thing started. Pulled the spark plugs. The gap was a bit narrow. Re-gapped them. Finally got it started, but it won't idle without choke. I've tried to adjust the one adjustment on the carb. The bike just dies at idle speed. When I'm riding and I release the throttle, the bike literally dies. I give it gas, is bogs down and jumps forward as it catches. Once I have the throttle open a bit, the throttle responds well. Just can't run it at an idle.

Any suggestions on curing my carb woes????

I want to ride my bike!!!

katoranger · 04-05-2008, 02:17 PM

First, replace the plugs with NGKs.

Then you need to remove the carb and do the c-clip on the needle adjustment and put it all the way to the notch near the pointy end.

Instructions are in the dual-sport prep thread.

After that you may need to adjust the fuel screw alittle, but most likely you need to turn up the idle screw so it idles at about 1200-1500rpm.

My bike would die too at first until I did the above mods.

You will need to adjust the idle after the engine breaks in again.

The varnish smell is the paints and coatings on the engine burning off.

Now, if those mods don't help then you may have some manufacturing debri in the carb from the gas tank.

Allen

katoranger · 04-05-2008, 02:38 PM

This is you setup. That carb is different than what most of us have.

Bruce at EJcycles might know that one better.

I believe you need to remove the cover from the top and then you will see a diaphragm. Under the diaphram will be a slide that should have the needle in it. You can change the clip setting there.

Cheryl · 04-05-2008, 03:00 PM

Yes. That looks like my engine and carb setup. I'm not sure about the adjustment your referring to (the clip setting). I'll check the other thread for more info. I was hoping to not remove the carb. It looks to be quite painful with all the hose attachments and such.
I guess the clip setting can only be done with the carb removed?

I think you have a good handle on what my symptoms and problems are. I really appreciate the help. Keep following me. I'll try to do the things you've recommended. I'll probably need more help.

katoranger · 04-05-2008, 03:06 PM

You may not have to remove the carb. If you can reach that top cover and take out the screws holding it on without removing the carb then you can probably adjust the carb needle without removing the carb.

The diaphragm looks like a piece of flat rubber and the slide will be atttached to it. Just pull it out. Take some pictures if possible so we can help visually.

At least you only have one carb to work on.

Allen

henkri · 04-05-2008, 03:14 PM

My impression is that many chinese bikes are jetted very lean. Probably due to get low emmision values. In many cases the bikes seems very happy with a slightly larger main jet.

katoranger · 04-05-2008, 03:18 PM

Here is another pic of your carb.

The adjuster screw on the lower right is the idle adjustment.

The cap on the top is what you need to remove to get to the slide and needle. You can probably do it with the carb on the bike and removing the gas tank for access.

Take that off and pull out the slide and the take some pics to show us, but it should have a c-clip on the needle, move it down so it raise the needle portion up.

I would move it as far down as possible.

The air/fuel screw location is on the opposite side of the carb in the pic. Not real sure on that.

Allen

Cheryl · 04-05-2008, 03:56 PM

http://mefast.com/LIFAN/MOTORCYCLE/L...ke/Intake.html

Sorry, that's not my carb.
If you go to the above web site, you'll see what my carb looks like. It doesn't really match the picture that you sent. The bowl is on the side. The outlet is at the bottom and it Y's down into both cylinders. The "intake" is at the top.

It's a Mikuni, but I don't know what model. All I can see is the brand name. Maybe next weekend I can pull the tank and get a better look. I work 12 hour shifts, Sunday thru Wednesday. I won't be able to do much more to it this week.

I added some Chevron Techron this morning. It has helped some, but it's still not right. Maybe that's because of the higher octane. I only put 87 octane in it to begin with.

I checked the other string, but didn't see anything about the c-clip adjustment. Just the main jet replacement.

I have 20 miles on it. WOO!! WOO!!

katoranger · 04-05-2008, 04:02 PM

The circle portion with the gold colored piece inside would be on the bottom with that carb in the picture putting the bowl on the side to the front.

Adjusting the idle should only take a few minutes with your fingers. That should at least help the dying problem.

Turn the knob clockwise about and listen to the engine since you don't have tach. Turn it until it stays running without the choke. That may be about 1500-2000rpm for now. Probably lower after breakin and the carb needle is adjusted.

Allen

Cheryl · 04-05-2008, 05:00 PM

Sorry to second guess you. I just went out and adjusted my idle. It is now running at idle. I rode it at low speeds (just in my neighborhood). It still bogs down and then jumps when I give it gas from an idle speed. Makes it a little tough around the corners, having to anticipate if the bike's going to jump and try to throw you. Anyway, it runs better today than yesterday.

I looked at my carb and I see the chrome cap on the right side of the bike. The bowl is on the left side. I should be able to get that cap off without having to remove the carb. I'll just take remove the tank and a little thing someone called a fuel pump. It's not an electric pump.

I'll charge up the batteries in my camera and try to get some pictures during the next week.

Thanks....and keep watching. Appreciate your help.

katoranger · 04-05-2008, 10:07 PM

Moving the needle will probably solve that bogging problem.

Allen

250Brider · 04-07-2008, 01:01 AM

Quote:

Originally Posted by Cheryl

I'll just take remove the tank and a little thing someone called a fuel pump. It's not an electric pump.

That chrome piece shaped like a hexagon located under the tank is a vacuum valve. Your bike has a vacuum operated petcock system.

Now ya know..

After 50 years of no problems with petcocks, Im not clear as to the reason we now have to have them.. but, have them we have..

Ride Lifan, Ride it with Pride and Ride Safe!!

bigpaws · 04-07-2008, 05:05 PM

Cheryl,

You can get the gas tank off rather easily removing the bolt under the seat, then sliding it off. You should take out the 4 bolts holding the "fuel pump" (vacuum activated) and it can be slid back without disconnecting any hoses or spilling fuel all over the place. Carefully remove the rubber hose connecting the carb to the airbox on the frame, and you should be able to see what's going on.

This carb doesn't have a traditional needle valve to adjust lean/rich mixture like on a car. It's preset, and the needle mod is the only thing you can do to change anything.

Good luck with your cruiser...and if you haven't already, be sure to dump and change the oil if you were like me and just added new oil instead of dumping the junk oil that came from China. My bike is currently broken as a result of this expensive mistake. The bearings gave up at 1300km.

Ride safe.

Cheryl · 04-08-2008, 09:42 AM

Yeh. I read your story. Sorry to hear about that. I stopped at the motorcycle store yesterday and picked up some high quality oil. I've only put 22 miles (or it may be km's) on it. Was your odometer km or miles? I was reading someone else's story and now I'm wondering about mine. I haven't had a chance to take it out this week. I work 12 hour shifts with 2 hours of communting.
Of course, my commute is not too bad. 27 miles down US1 to Key West, FL. Gulf on one side and Atlantic on the other. I have a bigger chance of drowning than crashing with a car.
I'll have to take pictures of my first commute.

bigpaws · 04-08-2008, 12:02 PM

if your speedometer maxes out at 140 and not 85, it's in km, as is the odometer. if you want to really check, 1 mile = 1.6 km...check the mileage at one mile post on us-1, and see if more than one "mile" has passed once you get to the next one. also, my speedo was off by about 5% (read too high) compared to radar checks here (have next to dangerous intersections...to warn you photo radar & red light camera is ahead).

i've only been to the keys once, back in 2000. i really liked it a lot. it's not surprising you work 12 hours there...most people i talked to had at least 2 jobs, and some of them 3. just watch out for hurricaines

my virago just passed smog yesterday, and i'm enjoying it already. i've chopped up 90% of the lifan for parts, and the seat is especially more comfortable than the stock virago seat.

04-04-2008, 11:45 PM	#1
Cheryl Join Date: Apr 2008 Location: Key West, FL Posts: 24	Carb problems on my new 250 I just got a new LF250. It came in a box. After assembling it, I had a hard time getting the thing started. Pulled the spark plugs. The gap was a bit narrow. Re-gapped them. Finally got it started, but it won't idle without choke. I've tried to adjust the one adjustment on the carb. The bike just dies at idle speed. When I'm riding and I release the throttle, the bike literally dies. I give it gas, is bogs down and jumps forward as it catches. Once I have the throttle open a bit, the throttle responds well. Just can't run it at an idle. Any suggestions on curing my carb woes???? I want to ride my bike!!!
	0

04-05-2008, 02:17 PM	#2
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	First, replace the plugs with NGKs. Then you need to remove the carb and do the c-clip on the needle adjustment and put it all the way to the notch near the pointy end. Instructions are in the dual-sport prep thread. After that you may need to adjust the fuel screw alittle, but most likely you need to turn up the idle screw so it idles at about 1200-1500rpm. My bike would die too at first until I did the above mods. You will need to adjust the idle after the engine breaks in again. The varnish smell is the paints and coatings on the engine burning off. Now, if those mods don't help then you may have some manufacturing debri in the carb from the gas tank. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-05-2008, 02:38 PM	#3
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	This is you setup. That carb is different than what most of us have. Bruce at EJcycles might know that one better. I believe you need to remove the cover from the top and then you will see a diaphragm. Under the diaphram will be a slide that should have the needle in it. You can change the clip setting there. __________________ You meet the nicest people on a Honda Clone.
	0

04-05-2008, 03:06 PM	#5
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	You may not have to remove the carb. If you can reach that top cover and take out the screws holding it on without removing the carb then you can probably adjust the carb needle without removing the carb. The diaphragm looks like a piece of flat rubber and the slide will be atttached to it. Just pull it out. Take some pictures if possible so we can help visually. At least you only have one carb to work on. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-05-2008, 03:18 PM	#7
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Here is another pic of your carb. The adjuster screw on the lower right is the idle adjustment. The cap on the top is what you need to remove to get to the slide and needle. You can probably do it with the carb on the bike and removing the gas tank for access. Take that off and pull out the slide and the take some pics to show us, but it should have a c-clip on the needle, move it down so it raise the needle portion up. I would move it as far down as possible. The air/fuel screw location is on the opposite side of the carb in the pic. Not real sure on that. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-05-2008, 03:00 PM	#4
Cheryl Join Date: Apr 2008 Location: Key West, FL Posts: 24	Yes. That looks like my engine and carb setup. I'm not sure about the adjustment your referring to (the clip setting). I'll check the other thread for more info. I was hoping to not remove the carb. It looks to be quite painful with all the hose attachments and such. I guess the clip setting can only be done with the carb removed? I think you have a good handle on what my symptoms and problems are. I really appreciate the help. Keep following me. I'll try to do the things you've recommended. I'll probably need more help.
	0

04-05-2008, 03:14 PM	#6
henkri Join Date: Apr 2008 Posts: 5	My impression is that many chinese bikes are jetted very lean. Probably due to get low emmision values. In many cases the bikes seems very happy with a slightly larger main jet.
	0

04-05-2008, 03:56 PM	#8
Cheryl Join Date: Apr 2008 Location: Key West, FL Posts: 24	http://mefast.com/LIFAN/MOTORCYCLE/L...ke/Intake.html Sorry, that's not my carb. If you go to the above web site, you'll see what my carb looks like. It doesn't really match the picture that you sent. The bowl is on the side. The outlet is at the bottom and it Y's down into both cylinders. The "intake" is at the top. It's a Mikuni, but I don't know what model. All I can see is the brand name. Maybe next weekend I can pull the tank and get a better look. I work 12 hour shifts, Sunday thru Wednesday. I won't be able to do much more to it this week. I added some Chevron Techron this morning. It has helped some, but it's still not right. Maybe that's because of the higher octane. I only put 87 octane in it to begin with. I checked the other string, but didn't see anything about the c-clip adjustment. Just the main jet replacement. I have 20 miles on it. WOO!! WOO!!
	0

04-05-2008, 04:02 PM	#9
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	The circle portion with the gold colored piece inside would be on the bottom with that carb in the picture putting the bowl on the side to the front. Adjusting the idle should only take a few minutes with your fingers. That should at least help the dying problem. Turn the knob clockwise about and listen to the engine since you don't have tach. Turn it until it stays running without the choke. That may be about 1500-2000rpm for now. Probably lower after breakin and the carb needle is adjusted. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-05-2008, 05:00 PM	#10
Cheryl Join Date: Apr 2008 Location: Key West, FL Posts: 24	Sorry to second guess you. I just went out and adjusted my idle. It is now running at idle. I rode it at low speeds (just in my neighborhood). It still bogs down and then jumps when I give it gas from an idle speed. Makes it a little tough around the corners, having to anticipate if the bike's going to jump and try to throw you. Anyway, it runs better today than yesterday. I looked at my carb and I see the chrome cap on the right side of the bike. The bowl is on the left side. I should be able to get that cap off without having to remove the carb. I'll just take remove the tank and a little thing someone called a fuel pump. It's not an electric pump. I'll charge up the batteries in my camera and try to get some pictures during the next week. Thanks....and keep watching. Appreciate your help.
	0

04-05-2008, 10:07 PM	#11
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Moving the needle will probably solve that bogging problem. Allen __________________ You meet the nicest people on a Honda Clone.
	0

04-07-2008, 05:05 PM	#13
bigpaws Join Date: Mar 2008 Location: Arizona, Dalian China Posts: 21	Cheryl, You can get the gas tank off rather easily removing the bolt under the seat, then sliding it off. You should take out the 4 bolts holding the "fuel pump" (vacuum activated) and it can be slid back without disconnecting any hoses or spilling fuel all over the place. Carefully remove the rubber hose connecting the carb to the airbox on the frame, and you should be able to see what's going on. This carb doesn't have a traditional needle valve to adjust lean/rich mixture like on a car. It's preset, and the needle mod is the only thing you can do to change anything. Good luck with your cruiser...and if you haven't already, be sure to dump and change the oil if you were like me and just added new oil instead of dumping the junk oil that came from China. My bike is currently broken as a result of this expensive mistake. The bearings gave up at 1300km. Ride safe.
	0

04-08-2008, 09:42 AM	#14
Cheryl Join Date: Apr 2008 Location: Key West, FL Posts: 24	Yeh. I read your story. Sorry to hear about that. I stopped at the motorcycle store yesterday and picked up some high quality oil. I've only put 22 miles (or it may be km's) on it. Was your odometer km or miles? I was reading someone else's story and now I'm wondering about mine. I haven't had a chance to take it out this week. I work 12 hour shifts with 2 hours of communting. Of course, my commute is not too bad. 27 miles down US1 to Key West, FL. Gulf on one side and Atlantic on the other. I have a bigger chance of drowning than crashing with a car. I'll have to take pictures of my first commute.
	0

04-08-2008, 12:02 PM	#15
bigpaws Join Date: Mar 2008 Location: Arizona, Dalian China Posts: 21	km/miles. if your speedometer maxes out at 140 and not 85, it's in km, as is the odometer. if you want to really check, 1 mile = 1.6 km...check the mileage at one mile post on us-1, and see if more than one "mile" has passed once you get to the next one. also, my speedo was off by about 5% (read too high) compared to radar checks here (have next to dangerous intersections...to warn you photo radar & red light camera is ahead). i've only been to the keys once, back in 2000. i really liked it a lot. it's not surprising you work 12 hours there...most people i talked to had at least 2 jobs, and some of them 3. just watch out for hurricaines my virago just passed smog yesterday, and i'm enjoying it already. i've chopped up 90% of the lifan for parts, and the seat is especially more comfortable than the stock virago seat.
	0