2005 MFC 100cc 2 stroke dirtbike questions??

[lovethegio]

hello everyone, been a yr since i have been here but now I have a few MFC dirtbike questions...

Has no air box and carb boot/manifold (rubber one from case to carb) is pretty bad....i put it back tegether with a cone style filter and dropped the needle 2 positions to fatten it up incase and it stars and idles or runs good....but it seems to not hit the powerband and it stalls everytime i try to drive it...I am about 240...the case is prob dirty as sh*t cuz it is hard to hit neurtral too...so gona sea foam it to clean it up after i get it too run right...so i also noticed that the slide was not going all the way up....is this common for these cables to stretch or is this normal....there is about 1/2 inch slade still hangin down at wot....also now that i ran it I see the seal behind the sprocket is pissing badly....we have no dealer for these around and am having a heard time getting any parts....being a 2005 100cc 2-stroke it seems rare and dont know if its worth fixing?? whats the info on these and are they good bikes....only thing i liked was the 120 psi comp....everything else is givving me a headache....any help and advise is appreciated very much!
thanks

[Weldangrind]

I remember the guy in Langley selling the MFC bikes out of a wood pellet stove shop, but I can't recall what they're based on. May we see a pic so we can try to offer guidance?

[lovethegio]

here are a few pics of the bike and motor it is 98 cc and a 2 stroke but i cant find any other bikes with the same configuration of the cylinder and carb....thanks for any help









if you would like more pics of the whole bike i could do that too....i think it would be a cool bike if i could get it to not stall.....i just dont get why it runs so good with no load but stalls everytime i try to move it....i have q-bonded the boot back together and am using electrical tape to temporarily seal it up...ican idle it and give it a shot of oxy around the flange without an increase of rpm, and it starts good so i am assuming it is sealing good enough for testing untill i can figure out what the issue is, and replace everything
thanks again for the help

[Weldangrind]

Thanks for the pics. Now that I see it, I recall looking at them in the showroom. I've never seen a cylinder head like that before. Does anybody else have any ideas about the origin of this engine?

I've found that two-smokes are particularly sensitive to both airflow and float level. You're on the right track by dropping the needle, but that only affects part throttle. My guess is that you're running out of fuel, and that a larger main jet is needed. If you remove the main jet and measure it, you might be able to find a similar jet on www.jetsrus.com

Also, I'd use a foam pod filter instead of a cone style. A properly oiled foam pod will more closely emulate the original airbox.

Have you checked the float level? Have you cleaned the carb, jets and passages? To check the float level, remove the float bowl and set the carb upside down on a flat surface. There should be a parting line in the float plastic, and you can compare it with the gasket surface of the bowl. Use that as a reference, and you can then gently bend the tab up or down to change the float level, and you can always put it back where you found it if it gets worse.

I've never seen a throttle cable stretch to the point that the throttle won't open fully. What is the second cable in the carb for? I'm guessing it's the oil injector. If it's an injector cable, you need to be careful about timing (for lack of a better term) between the throttle cable and the injector cable. Please show us a pic of how the injector works, and we might be able to guide you on setting the cable. There is also the possibility that you can easily shorten the throttle cable, but that's a last resort.

If you examine the seal behind the countershaft sprocket, it should have three numbers on it. Take those numbers to the local bearing shop, and they'll be able to match up the seal. Which Province do you live in? I'm guessing BC, since that's the only mention of MFC I've heard of.

[lovethegio]

i did clean the carb and made sure all holes and both jets were cleaned, a few times too to make sure it wasnt that...the second cable you see on the carb is choke...plunger style choke on this carb, and other cable connected to the twist grip goes to the oil injection...with the cables on it now it leaves the slide down about 1/2 inch, i had elliminated this as reason for it stalling by disconnecting the oil injection cable and running premix and it does rev a bit higher as i can open the carb up fully but still stalls when i try to get going......I am able to pull a plug and manually roll the bike in gear with no issues but this motor just doesnt seem to have enough to drive it.....i have never seen this before...I live in ontario and we actually have a dealer here but he is closed til monday,and is a known idiot and doubt he can help me but def worth a shot...he also doesnt sell the bikes anymore but still has some parts and a sign up at his tire shop...right now the carb boot/manifold is the most important part as i can find the filter and seals locally that should work....I will check the float level but it was a brass float and it wasnt cracked but could have been low....I just assumed that it would have been set right as i dont think anyone has touched it but will def try to change the level after measuring it to see if that helps....do u think it is a possibility that a bearing is gone inside the case and is binding it up to stall but when i roll it it is taking power from the other side of the drivetrain and not binding??? I am almost stumped.....thanks for all the help and tips and i will post some pics of the slide hangin down with wot to show u what i mean...thanks again for all your help...maybe i should be sea foaming the case to clean it up first to make sure no sludge and grime are causing this....i just didnt want to waste a bottle of seafoam if it is a lost cause...

[humanbeing]

Suzuki AX100???
http://jd-motor.en.alibaba.com/produ...or_partes.html

[lovethegio]

so i went back out side to take some pics for you, and i also noticed that out of the full throttle movement 25 % was freeplay, felt resistance in the next 50% then the last 25% moved the slide up from first pic to second.....I am thinkin this bike is a disaster....so abviously not getting wot.....also prob dumpin allot of oil in there as it feels like i am opening the gate after 25% movement....thinkin of just draining the res of oil, and running pre mix and to see if i can get it to go without stalling....I am hoping this sounds logical to you too cuz i have never seen this kind of issues on a bike that looks fairly new....

[lovethegio]

sorry forgot the other two pics.....and thanks for all your help!



sorry pics arent perfect but u can see what i am talking about

[oviking99]

I agree with Weld. I think it is running lean. I use electrical tape and wrap the cone filter a few times to cut down on air flow, add or subtract tape as needed. I have had good results, but I think I would still let the oil injector do it's job. I'm not sure, but I think there is a 'throttle mixture curve' that needs to happen. Obviously it won't happen with premix.

[Weldangrind]

Thanks OV; throttle mixture curve is what I was trying to say.

Lovethegio, is there a way to sort out the throttle cable with adjustments at the throttle tube or carb cap? From the pic, it seems like it should have a rubber boot at the end of the cable, right where it meets the carb. I have some old Suzuki TS bikes with a boot like that. Without the boot, the cable housing would sit too low and have excess slack, just like you're seeing.

I would definitely not dump Seafoam into the bottom end; just change the oil for some 15W40 diesel oil of your choice. I typically use Rotella, but I'll use whatever is on sale at Walmart.

Once again, Humanbeing has saved the day. I agree with him that your engine is cloned from the Suzuki AX100. http://en.wikipedia.org/wiki/Suzuki_AX100 I found a carb boot on www.taobao.com for 8 CNY, which converts to about $1.36 Canadian. I've bought several parts through Taobao. See it here: http://item.taobao.com/item.htm?spm=a230r.1.14.255.4F0YDF&id=15500146045

I also found a user manual online (remember that it is for the engine only; the rolling chassis will be different). Page 17 shows clutch and oil pump adjustment: http://oldraremotorcycles.blogspot.c...page_4888.html

A word of caution: don't disable the injector and run premix. My guess is that the injector is like the TS Suzukis, and it feeds the left main crank bearing as well as mixes with gas. If you run premix, you'll starve the left main bearing and you'll lean out your mixture.

With Humanbeing's contribution, there's hope for this bike!

[Weldangrind]

Ok, I found some more stuff of interest:

Service manual for $6.80 Canadian: http://item.taobao.com/item.htm?spm=a230r.1.14.218.peDgd1&id=13336141253

Oil seal kit for $1.70 Canadian: http://item.taobao.com/item.htm?spm=a230r.1.14.250.peDgd1&id=17261635244

Throttle / injector cable for $1.36 Canadian: http://item.taobao.com/item.htm?spm=a230r.1.14.304.peDgd1&id=10419063715

Here are some pages for you to check out. Just open a second tab, type CYN to CAD into Google, and prepare to be amazed by the priices:

http://s.taobao.com/search?spm=a230r.1.4.2.cbyERl&q=ax100%B7%A2%B6%AF% BB%FA&rsclick=2&promote=0&tab=all&bcoffset=4&s=NaN #J_relative

http://s.taobao.com/search?spm=a230r.1.4.3.cbyERl&q=%C1%E5%C4%BEax100& rsclick=3

http://s.taobao.com/search?spm=a230r.1.4.5.cbyERl&q=%BD%F0%B3%C7ax100& rsclick=5

[humanbeing]

http://chinariders.net/showthread.php?t=9957 PM "bigheavy150" if still had problems.
---
Mexico version:
http://suzuki.com.mx/motos/ax100/
http://bv000245.ferozo.com/despieces/SUZUKI/AX100.pdf
---
Columbia version:
http://suzumamoto2.com/descargas/suz...)%20Ingles.pdf K3-K6
http://www.diagramasde.com/diagramas...2/AX-100-2.pdf K6-K8

[Weldangrind]

I looked at each of the manuals that Humanbeing posted, and this one is the clearest: http://www.diagramasde.com/diagramas/otros2/AX-100-2.pdf I recommend that you use the "Save target as" feature, and keep it on your hard drive. Check out Figure 5, and you'll see item #20, which is the rubber boot I was trying to explain.

[lovethegio]

you guys are awesome!!! thats the info i needed to get this thing going....there is a rubber boot at the bottom of the cable and as far as oil injection on 2 strokes the only experience i have is sled, which i have deleted a few for racing reasons...weight, a gauranteed thing as well and as far as a mixture curve goes...i had no idere about that....but i am daddy daycare this weekend and will not have a whole lot of time to spend out in the garage until 7 ish pm here, and idont have a zuki dealership to get parts from but will definitely spend some time reading through all the material you guys provided to me....thankyou very much....and it seem that the knowledge in this forum extends way beyond off shore bikes.....so I will go through this thing with a fine tooth comb now that i can have some specs to follow....thanks again and i will keep everyone posted on how this turns out.....once this is done i will also share my gio-saki pics and adventures too.....gio with a kdx 175 motor in it...lol sweet ride!!
thanks again everyone
cheers!

[Weldangrind]

Happy to help! I'm somewhat of a vintage Suzuki nut, so this project really captured my interest. If an MFC bike comes along at the right price, I might grab it just for the motor, since it's suitable as a dual sport engine in a small bike.

I gotta see your Gio-saki! Please start a new thread and show us!