2005 MFC 100cc 2 stroke dirtbike questions?? - Page 2

lovethegio · 09-09-2013, 02:57 PM

okay guys I tried everything to fatten it up with no improvements.....the easiest way to make it rev is wot on the stand in first gear and give it a shot of oxygen at carb filter and she picks up nicely.....so i put the needle in the top position with no bennefit....oil injection now properly set, was also dumping allot of oil as it was overly adjusted....but it seams to be it is running super rich and now i am wondering if it was needle and seat this whole time...I am gonna try to verify it by blowing into the fuel feed with it full, but if that is not a culprit....which i doubt....what else could cause a rich running engine....needle and needle jet look fine, everything doesnt look like it has much wear to it....could reads cause this??? more air= rev under load.....so this to me means running rich but just dont get it how??? unless needle and seat...well i will post results in an hour.....i hope thats what it is...

was just thinking a bit....and also noticed that the carb did not have the washer between the main jet and needle jet...which i thought was weird but figured that was how it was made as there was still a groove holding the needle jet in....but after looking at the parts diagrams for this engine it def has that washer..this would obviously affect jetting but i would think it would result in a leaner condition....almost scratching my head....hmmm

lovethegio · 09-09-2013, 06:08 PM

mfc is on right with some electrical tape to make better seal and skidoo is on left....note missing washer...

just a close up

now i am thinkin oxy just made better boom cuz thats just what it does and it was getting lean cuz the jet was too high up resulting in same affect as raising needle c clip position....a leaner mixture....i just cant find one that fits out of all my carbs so i think i gotta order one....does this make sense cuz i think i am going crazy over this thing now.....thanks
cheers

Weldangrind · 09-09-2013, 11:52 PM

I still think it's lean. Two-smokes are particularly sensitive to airflow changes, so a non-stock (and more free-flowing) air filter will mess it up. What is the OD of the carb inlet?

I wouldn't focus on the reeds yet. Conquer the carb first, and eliminate it as a possibility.

I'm glad that you were able to set the oil injector. Are there instructions in the owners manual for float height? Since the engine and carb setup are likely to be identical to an AX100, you should be able to follow that spec.

If it comes down to it, you could certainly order a new carb on Taobao, along with whatever else you need. Those parts are cheap as chips.

lovethegio · 09-10-2013, 11:08 AM

i think i may have found a new carb for it, but also was on taobao and was amazed at pricing...but what is the timeline for shipping and what is the cost?? i noticed that there was an option for overseas shipping and it seem to recalculate the price but still had the total cost super low.....i geuss i am just a little skeptical about it as i have never used it before.....but a super cool site once u find out how to get it translated....
thanks

Weldangrind · 09-10-2013, 12:01 PM

I use Google Chrome for Taobao and let it translate automatically. It works well enough. Sorta.

You need an agent to buy from Taobao, and I use www.tbtrends.com . The shipping price you see with a part will cover the shipping cost to tbtrend's office. Simply copy the URL of a part that you want, paste it into a tbtrends order form and hit Add to Cart. After you're done shopping, click Checkout.

Tbtrends will send you an email with an invoice, and that covers the shipping to their office plus their fee. Once they have received all of your parts, they'll weigh them and calculate the shipping costs to your door. You generally have two choices: EMS (mail) or DHL. When I had a small package shipped by DHL, it arrived in two days! I find that EMS arrives in less than two weeks. Once a final shipping cost has been established, they'll ask for a final payment. As soon as you pay, they'll ship the goods to you.

Easy and painless.

lovethegio · 09-10-2013, 12:31 PM

so i also went to my local old dealer of mfc for parts and he says he got out of selling them because they went out of business...which i think was wrong...but he had no clue what he was talking about and was trying to sell me a carb for 50 bucks...i would rather buy a mikuni for that price...but today i am going to try to find a washer to hold that main jet and tube in the right spot and see what happens....last day of tinkering before i am giving up

humanbeing · 09-10-2013, 06:21 PM

Repair kit: http://item.taobao.com/item.htm?id=9648425105
Carb: http://item.taobao.com/item.htm?id=9624002471
Those item(s) is made in Fuding (aka "capital of carb") , Fujian
--
Data is stolen from http://amazon.cn/dp/B0011AI212/ref=s...qid=1378853862
https://plus.google.com/photos/photo...30034462637282

lovethegio · 09-10-2013, 08:07 PM

through a 145 main jet from my grizz figuring it was too big and def was....i measured the carb at intake side(air box) OD 42.73 ID 40.01 engine side OD 26.77 ID 21.77 no markings on main jet but is suppposed to be a 92.5...i dont have any way to measure other then sticking the smooth end of my tip cleaner in there to get an idea....any other methods to measure jets? tomorow i am still gonna try getting a few bigger jets from a motorcycle shop and try it one last time to see if its worth my time right now, when so many other projects need to be done....might get on hold for abit...after tomorow of course....lol

lovethegio · 09-10-2013, 08:15 PM

thanks humanbeing.....i am thinkin about time to order a few new parts....even the airbox if i can find it and have it back to stock.....after i try a few more jets tomorow though....i hope some bigger jets make an improvement and work....fingers crossed....hehe

humanbeing · 09-10-2013, 11:20 PM

The service manual http://saa.auto.sohu.com/mt/thread-t...lbaaaa-1.shtml was bundled

w/ the bike when bought it new in '86
--
CG125 (Lifan) vs AX100 (Jincheng) http://www.microsofttranslator.com/b...om/msg-32.html

Weldangrind · 09-11-2013, 01:13 AM

The factory airbox and filter is likely to be junk. This is a filter with a 42mm ID that I've used several times. It's quite good quality, and the price is right. I use Maxima Fab1 filter oil, and it sticks like cobwebs.

I use my numbered drill bit set to establish jet size on unknown jets. It's close enough to establish what you're working with.

09-09-2013, 02:57 PM	#16
lovethegio Join Date: Apr 2012 Posts: 26	okay guys I tried everything to fatten it up with no improvements.....the easiest way to make it rev is wot on the stand in first gear and give it a shot of oxygen at carb filter and she picks up nicely.....so i put the needle in the top position with no bennefit....oil injection now properly set, was also dumping allot of oil as it was overly adjusted....but it seams to be it is running super rich and now i am wondering if it was needle and seat this whole time...I am gonna try to verify it by blowing into the fuel feed with it full, but if that is not a culprit....which i doubt....what else could cause a rich running engine....needle and needle jet look fine, everything doesnt look like it has much wear to it....could reads cause this??? more air= rev under load.....so this to me means running rich but just dont get it how??? unless needle and seat...well i will post results in an hour.....i hope thats what it is... was just thinking a bit....and also noticed that the carb did not have the washer between the main jet and needle jet...which i thought was weird but figured that was how it was made as there was still a groove holding the needle jet in....but after looking at the parts diagrams for this engine it def has that washer..this would obviously affect jetting but i would think it would result in a leaner condition....almost scratching my head....hmmm Last edited by lovethegio; 09-09-2013 at 04:19 PM.
	0

09-09-2013, 11:52 PM	#18
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I still think it's lean. Two-smokes are particularly sensitive to airflow changes, so a non-stock (and more free-flowing) air filter will mess it up. What is the OD of the carb inlet? I wouldn't focus on the reeds yet. Conquer the carb first, and eliminate it as a possibility. I'm glad that you were able to set the oil injector. Are there instructions in the owners manual for float height? Since the engine and carb setup are likely to be identical to an AX100, you should be able to follow that spec. If it comes down to it, you could certainly order a new carb on Taobao, along with whatever else you need. Those parts are cheap as chips. __________________ 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

09-10-2013, 12:01 PM	#20
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I use Google Chrome for Taobao and let it translate automatically. It works well enough. Sorta. You need an agent to buy from Taobao, and I use www.tbtrends.com . The shipping price you see with a part will cover the shipping cost to tbtrend's office. Simply copy the URL of a part that you want, paste it into a tbtrends order form and hit Add to Cart. After you're done shopping, click Checkout. Tbtrends will send you an email with an invoice, and that covers the shipping to their office plus their fee. Once they have received all of your parts, they'll weigh them and calculate the shipping costs to your door. You generally have two choices: EMS (mail) or DHL. When I had a small package shipped by DHL, it arrived in two days! I find that EMS arrives in less than two weeks. Once a final shipping cost has been established, they'll ask for a final payment. As soon as you pay, they'll ship the goods to you. Easy and painless. __________________ 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

09-10-2013, 06:21 PM	#22
humanbeing Join Date: Mar 2008 Posts: 2,436	Repair kit: http://item.taobao.com/item.htm?id=9648425105 Carb: http://item.taobao.com/item.htm?id=9624002471 Those item(s) is made in Fuding (aka "capital of carb") , Fujian -- Data is stolen from http://amazon.cn/dp/B0011AI212/ref=s...qid=1378853862 https://plus.google.com/photos/photo...30034462637282 Last edited by humanbeing; 03-31-2017 at 08:58 PM.
	0

09-10-2013, 11:20 PM	#25
humanbeing Join Date: Mar 2008 Posts: 2,436	The service manual http://saa.auto.sohu.com/mt/thread-t...lbaaaa-1.shtml was bundled w/ the bike when bought it new in '86 -- CG125 (Lifan) vs AX100 (Jincheng) http://www.microsofttranslator.com/b...om/msg-32.html Last edited by humanbeing; 09-10-2013 at 11:54 PM.
	0

09-09-2013, 06:08 PM	#17
lovethegio Join Date: Apr 2012 Posts: 26	mfc is on right with some electrical tape to make better seal and skidoo is on left....note missing washer... just a close up now i am thinkin oxy just made better boom cuz thats just what it does and it was getting lean cuz the jet was too high up resulting in same affect as raising needle c clip position....a leaner mixture....i just cant find one that fits out of all my carbs so i think i gotta order one....does this make sense cuz i think i am going crazy over this thing now.....thanks cheers
	0

09-10-2013, 11:08 AM	#19
lovethegio Join Date: Apr 2012 Posts: 26	i think i may have found a new carb for it, but also was on taobao and was amazed at pricing...but what is the timeline for shipping and what is the cost?? i noticed that there was an option for overseas shipping and it seem to recalculate the price but still had the total cost super low.....i geuss i am just a little skeptical about it as i have never used it before.....but a super cool site once u find out how to get it translated.... thanks
	0

09-10-2013, 12:31 PM	#21
lovethegio Join Date: Apr 2012 Posts: 26	so i also went to my local old dealer of mfc for parts and he says he got out of selling them because they went out of business...which i think was wrong...but he had no clue what he was talking about and was trying to sell me a carb for 50 bucks...i would rather buy a mikuni for that price...but today i am going to try to find a washer to hold that main jet and tube in the right spot and see what happens....last day of tinkering before i am giving up
	0

09-10-2013, 08:07 PM	#23
lovethegio Join Date: Apr 2012 Posts: 26	through a 145 main jet from my grizz figuring it was too big and def was....i measured the carb at intake side(air box) OD 42.73 ID 40.01 engine side OD 26.77 ID 21.77 no markings on main jet but is suppposed to be a 92.5...i dont have any way to measure other then sticking the smooth end of my tip cleaner in there to get an idea....any other methods to measure jets? tomorow i am still gonna try getting a few bigger jets from a motorcycle shop and try it one last time to see if its worth my time right now, when so many other projects need to be done....might get on hold for abit...after tomorow of course....lol
	0

09-10-2013, 08:15 PM	#24
lovethegio Join Date: Apr 2012 Posts: 26	thanks humanbeing.....i am thinkin about time to order a few new parts....even the airbox if i can find it and have it back to stock.....after i try a few more jets tomorow though....i hope some bigger jets make an improvement and work....fingers crossed....hehe
	0

09-11-2013, 01:13 AM	#26
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	The factory airbox and filter is likely to be junk. This is a filter with a 42mm ID that I've used several times. It's quite good quality, and the price is right. I use Maxima Fab1 filter oil, and it sticks like cobwebs. I use my numbered drill bit set to establish jet size on unknown jets. It's close enough to establish what you're working with. __________________ 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