Smoking gun (Lifan 200gy)

Thorgram · 05-30-2010, 04:21 PM

Awhile back I told the story of dumping my bike in a 4 wheelers mud hole, well I took the great advice I got on here, flushed the engine several times among other things and now have it back in action.

Everything seemed to be good for the first week or so but today I had it out for an extended ride and after about 30 minutes I pulled to a stop sign and wondered if I was on fire or something. Tons of light blue/white smoke was coming from the exhaust. First I checked the choke to see if it was running rich or lean that way, that wasn't it. By the time I got home it looked like I was riding an old 2 stroke.

When I got home I checked the oil to see if maybe I was getting a fuel/oil mix going on because of bad rings or something along those lines. The oil didn't smell gassy or burn when I tried a lighter test. (away from the bike of course) The only thing I can think of is the carb running too rich, there was oily residue on the end of the exhaust. I haven't checked the plug yet, the engine was still too hot. Why the carb would be doing this NOW would seem odd since I haven't messed with it latley.

If it ends up being a carb problem I'm not too worried since I ordered a new MIKUNI 30mm yesterday. I look forward to the expert opinions out there.

TurboT · 05-30-2010, 04:28 PM

If you're blowing a lot of blue smoke and have oily residue in the exhaust it's very unlikely a carb problem.

You may not have flushed it out completely and the extended running just allowed the left over dirt to eat your cylider walls and take out your rings, or, you had muck in the valve guides and it ate your guides allowing too much oil in. The second scenario is unlikely as it would probably run like crap (no compression) if the guide was really worn out.

Hate to be the bearer of bad news but it sounds like you may need to take apart your motor.

Weldangrind · 05-30-2010, 04:30 PM

Blue smoke indicates oil burning, and black smoke indicates an overly-rich condition. I'm guessing that your symptoms are a result of poor venting. Check the vent tube that is attached to the top of the engine and make sure it's clear and not pinched.

When excessive pressure builds up inside an engine (as is the case with all four stroke engines), it needs a way out, or it'll find one.

TurboT · 05-30-2010, 04:32 PM

Quote:

Originally Posted by Weldangrind

Blue smoke indicates oil burning, and black smoke indicates an overly-rich condition. I'm guessing that your symptoms are a result of poor venting. Check the vent tube that is attached to the top of the engine and make sure it's clear and not pinched.

When excessive pressure builds up inside an engine (as is the case with all four stroke engines), it needs a way out, or it'll find one.

Or it could be that.. :P

Thorgram · 05-30-2010, 04:52 PM

Checked the vent tube and it wasn't pinched in anyway, it was actually half dry rotted and when I moved it it broke the rest of the way.

Some of the oily poop was on the vent as well. It may be that a case of engine rebuild is in my future?

Cal25 · 05-30-2010, 06:13 PM

Or just buy a new one.

BrianW · 05-30-2010, 08:20 PM

I may have any parts you might need, if a rebuild is the case.

Buying a new one is a good idea, too.

MICRider · 05-30-2010, 08:36 PM

Just wondering, did it use some oil on your extended ride? And if so, how much? If it did use a bunch of oil you could do a cylinder leakdown test on it to see where it's leaking and then decide on a repair route from there. Hope it's nothing major but it sounds kind of nasty.

Thorgram · 05-31-2010, 09:59 AM

It did appear to have used some oil. I checked it before I went and it was a bit lower after I was done. Maybe I'll rip into it today and see what I find. If I find anything cool/horrid I may post some pictures.

Buzzkill · 05-31-2010, 09:27 PM

Did the engine suck up water into the combustion chamber, if it did and the motor hydro locked then your problem is most likely a cracked piston ring due to a massive compression of water in the cylinder. It will go for a little while until the broken ring wears a groove in the cylinder wall allowing alot of oil to pass into the combustion chamber. A simple test would be to remove the dipstick and run the engine to see if it is getting alot of blow buy, if you have pressure(compression) blowing out the oil fill you most likely killed the motor.

Wild_Alaskan · 05-31-2010, 11:53 PM

as a general rule if it smokes on acceleration its the rings cylinder, if it smokes on deacceleration it is valve guides. also leaking valve guides will NOT cause no compression.

also if your rings are cracked or have a similar problem resulting in low compression you should notice a loss in low end power, and possibly trouble idling

Wild_Alaskan · 05-31-2010, 11:55 PM

also make sure your connecting rod is straight.

if you get a new engine I would inquire about this "168-fml" that is advertised here

http://metricpartshq.com/shop2/index.php?cPath=25

Thorgram · 06-01-2010, 05:08 PM

I got the motor out and on my garage floor last night, I am prepared for the worst when I get down in there and see the potential carnage.

I checked out that link and I am somewhat amused that a new engine is pretty much the same price as an exhaust. Also rather sickened that you can get an engine there for that and on ebay they are selling for $1k.

Wild_Alaskan · 06-02-2010, 03:00 AM

holy crap! they were selling gy-5 engines for 350 6 months ago

Thorgram · 06-11-2010, 05:13 PM

Ok, I tore the engine down and have some pictures on photobucket to show what I saw.

http://s960.photobucket.com/albums/a...ifan%20Engine/

By the way, the pictures are in backwards order in case it looks odd.

Other than some ugly crud on the valves and top of the piston I didn't see anything that looked like obvious damage. The rings aren't broke or bent, nothing flops around all weird.

Could it have been something like the headgasket letting oil in? It didn't look blown or cracked but there was oil in the TOP of the cylinder. My realm of experience is in diesel engines, I've hardly ever touched small gas engines. Thoughts? Opinions?

05-30-2010, 04:21 PM	#1
Thorgram Join Date: Jan 2008 Posts: 145	Smoking gun (Lifan 200gy) Awhile back I told the story of dumping my bike in a 4 wheelers mud hole, well I took the great advice I got on here, flushed the engine several times among other things and now have it back in action. Everything seemed to be good for the first week or so but today I had it out for an extended ride and after about 30 minutes I pulled to a stop sign and wondered if I was on fire or something. Tons of light blue/white smoke was coming from the exhaust. First I checked the choke to see if it was running rich or lean that way, that wasn't it. By the time I got home it looked like I was riding an old 2 stroke. When I got home I checked the oil to see if maybe I was getting a fuel/oil mix going on because of bad rings or something along those lines. The oil didn't smell gassy or burn when I tried a lighter test. (away from the bike of course) The only thing I can think of is the carb running too rich, there was oily residue on the end of the exhaust. I haven't checked the plug yet, the engine was still too hot. Why the carb would be doing this NOW would seem odd since I haven't messed with it latley. If it ends up being a carb problem I'm not too worried since I ordered a new MIKUNI 30mm yesterday. I look forward to the expert opinions out there.
	0

05-30-2010, 04:30 PM	#3
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Blue smoke indicates oil burning, and black smoke indicates an overly-rich condition. I'm guessing that your symptoms are a result of poor venting. Check the vent tube that is attached to the top of the engine and make sure it's clear and not pinched. When excessive pressure builds up inside an engine (as is the case with all four stroke engines), it needs a way out, or it'll find one. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

05-30-2010, 04:52 PM	#5
Thorgram Join Date: Jan 2008 Posts: 145	Vent tube Checked the vent tube and it wasn't pinched in anyway, it was actually half dry rotted and when I moved it it broke the rest of the way. Some of the oily poop was on the vent as well. It may be that a case of engine rebuild is in my future?
	0

05-31-2010, 11:53 PM	#11
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	as a general rule if it smokes on acceleration its the rings cylinder, if it smokes on deacceleration it is valve guides. also leaking valve guides will NOT cause no compression. also if your rings are cracked or have a similar problem resulting in low compression you should notice a loss in low end power, and possibly trouble idling __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
	0

05-31-2010, 11:55 PM	#12
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	also make sure your connecting rod is straight. if you get a new engine I would inquire about this "168-fml" that is advertised here http://metricpartshq.com/shop2/index.php?cPath=25 __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
	0

05-30-2010, 04:28 PM	#2
TurboT Join Date: Sep 2008 Location: Surrey, B.C., Canada Posts: 2,185	If you're blowing a lot of blue smoke and have oily residue in the exhaust it's very unlikely a carb problem. You may not have flushed it out completely and the extended running just allowed the left over dirt to eat your cylider walls and take out your rings, or, you had muck in the valve guides and it ate your guides allowing too much oil in. The second scenario is unlikely as it would probably run like crap (no compression) if the guide was really worn out. Hate to be the bearer of bad news but it sounds like you may need to take apart your motor.
	0

05-30-2010, 06:13 PM	#6
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	Or just buy a new one.
	0

05-30-2010, 08:20 PM	#7
BrianW Join Date: Feb 2008 Location: Wheeling, WV native currently living In Natchitoches, LA Posts: 297	I may have any parts you might need, if a rebuild is the case. Buying a new one is a good idea, too.
	0

05-30-2010, 08:36 PM	#8
MICRider Join Date: Oct 2009 Location: Alberta, Canada Posts: 3,274	Just wondering, did it use some oil on your extended ride? And if so, how much? If it did use a bunch of oil you could do a cylinder leakdown test on it to see where it's leaking and then decide on a repair route from there. Hope it's nothing major but it sounds kind of nasty.
	0

05-31-2010, 09:59 AM	#9
Thorgram Join Date: Jan 2008 Posts: 145	It did appear to have used some oil. I checked it before I went and it was a bit lower after I was done. Maybe I'll rip into it today and see what I find. If I find anything cool/horrid I may post some pictures.
	0

05-31-2010, 09:27 PM	#10
Buzzkill Join Date: Sep 2009 Posts: 53	Did the engine suck up water into the combustion chamber, if it did and the motor hydro locked then your problem is most likely a cracked piston ring due to a massive compression of water in the cylinder. It will go for a little while until the broken ring wears a groove in the cylinder wall allowing alot of oil to pass into the combustion chamber. A simple test would be to remove the dipstick and run the engine to see if it is getting alot of blow buy, if you have pressure(compression) blowing out the oil fill you most likely killed the motor.
	0

06-01-2010, 05:08 PM	#13
Thorgram Join Date: Jan 2008 Posts: 145	I got the motor out and on my garage floor last night, I am prepared for the worst when I get down in there and see the potential carnage. I checked out that link and I am somewhat amused that a new engine is pretty much the same price as an exhaust. Also rather sickened that you can get an engine there for that and on ebay they are selling for $1k.
	0

06-02-2010, 03:00 AM	#14
Wild_Alaskan Join Date: Dec 2009 Location: Alaska Posts: 914	holy crap! they were selling gy-5 engines for 350 6 months ago __________________ Dune buggy build http://chinariders.net/modules.php?n...wtopic&t=14470 400cc lifan build vid: http://youtu.be/20HoU8OK_Y0 other fun: http://tinyurl.com/wildalaskan
	0

06-11-2010, 05:13 PM	#15
Thorgram Join Date: Jan 2008 Posts: 145	Ok, I tore the engine down and have some pictures on photobucket to show what I saw. http://s960.photobucket.com/albums/a...ifan%20Engine/ By the way, the pictures are in backwards order in case it looks odd. Other than some ugly crud on the valves and top of the piston I didn't see anything that looked like obvious damage. The rings aren't broke or bent, nothing flops around all weird. Could it have been something like the headgasket letting oil in? It didn't look blown or cracked but there was oil in the TOP of the cylinder. My realm of experience is in diesel engines, I've hardly ever touched small gas engines. Thoughts? Opinions?
	0