I own a Roketa MC-109-50. I am very interested in derestricting it so it can perform more to its true potential. I have tried to research this as much as possible but it seems as though everyone says something different. I just ordered, yet to receive, an unrestricted CDI, polygon sliders 5g, and a uni filter that came with a #85 main jet. When I replace the sliders I plan on removing the variator restricting washer as well
My main question is, what else can I or should I do to derestrict my scooter? I am also looking into changing the clutch and torque springs but what size (rpm) would be best? I could really use some input and help. Thanks in advance for the help!
Congrats on wanting to upgrade. The speed and fun factors of owning a scooter will definitely go up.
The exhaust will most likely be restrictive from the factory to control noise and emissions, so I would invest in a free flow one for sure. There are some nice pipes available online for less than $100. Keep in mind that with everything you do to change airflow (entering AND leaving the engine) you will need to tune the carb to compensate. The #85 jet might be perfect, but carb tuning is trial-and-error, so you'd have to luck out.
To my understanding, changing the clutch springs and main torque spring don't affect top speed (I just put up a thread asking about those parts actually). Stiffening the clutch springs improves acceleration because it keeps the clutch disengaged until you reach higher RPM's. When the clutch finally does grab, the engine is putting out more power than it was with your stock springs.
The torque spring affects your gear ratio by controlling the rear pulley. A stronger spring means you will stay in the lower ratios longer, giving you more low-end power (climbing hills, starting from a stop, etc.)
I think that the 1000 rated springs are the stock ones, but wait for another opinion before you buy. I really can't recommend anything because I haven't done anything with them myself, and it depends what you want.
Unrestricted "performance" CDI's will not help your performance at all unless you know for sure you have a restricted one in the first place. Most often, claims of an "advanced timing curve" simply don't exist and are just a sales gimmick.
For more overall engine power, definitely think about a 72cc big bore kit. It's not the easiest thing you can do and can take many hours if you've never done it before, but it will improve every aspect of performance.
Thanks for the reply 50seesee! I actually saw your post on clutch and torque springs right after I made this thread hah. I never even considered the exhaust to have restrictions. How difficult is it to switch to an unrestricted exhaust? Do you have any recommendations on one to buy? The more I research all the different things one can upgrade on their scooter the more overwhelmed I become! I am by no means an expert or even close. I get somewhat worried that I may upgrade something and damage my engine or worse. So by adding the uni filter and swapping out the main jet to a #85 you think that will work? I guess I shouldn't get too deep in thought on this since I am yet to even get my parts. As for changing the clutch/torque springs I am considering that because I want to increase the speed/capability of my hill climb. I had heard, as you said, that this upgrade is capable of doing just that. I will keep an eye on your thread to see about the sizes. Lastly, I have been on the fence about a BBK for a LONG time and I cannot decide. i have heard they are hard to install, especially for first timers (me). Also, that they are hard on your engine and decrease its life. I'm not sure if either are true. I feel as though these small upgrades are a good "beginner" project for me. Thanks again for the help thus far ;D
Take a look at that link for exhausts. I bought the exact package that's second from the top. It's a great pipe, but I had to rig a custom mount for it, as in go to home depot, measure a bunch of stuff, buy metal rods, cut them myself with a hacksaw, drill the right sized, holes, etc. For some stupid reason, the manufacturer decided not to include this invaluable part. It makes me frustrated all over again just thinking about it. Unless you enjoy custom work like that, I really wouldn't recommend it. The 6th kit from the top (same price as mine) APPEARS to include everything you need...
Now for the good news (lol): once you get the pipe you want, installation is a breeze. It literally is a bolt-on upgrade. To remove my original pipe, there were 4 bolts to unscrew, two easily visible from the side (for support) and two where the pipe connects to the engine. To attach your new pipe, it's a simple as lining up the holes and screwing the original bolts back on.
As far as getting the jetting to match your upgrades, I'd bet the #85 would cover the filter nicely. Put the exhaust on with it though, and you'll probably need to go higher (#88-#95 in most cases).
As will any upgrade that allows the engine to work harder, a BBK does increase engine wear. But on that same note, it's all relative. If you ride 5 MPH all the time, your engine will last a hell of a lot longer, but where's the fun in that? The reason I suggested the 72cc (as opposed to the 83cc) is because it's a great balance between engine longevity and performance. In fact, the 50cc GY6 engine is a clone of a Honda engine and was originally designed to displace 72cc anyway.
The installation is probably the most difficult and time-consuming project you can do to a scooter (besides a total rebuild), so you're smart to hold off on it for now if you're not 100% sure. Here's the guide I used during my install. It has pictures and step-by-step instructions.
Great stuff 50seesee, thanks again! You pretty much have me set on an exhaust now. I will most likely install the parts I just ordered then get an exhaust. Just to clarify, what can I expect to see as far as performance changes if I were to install a new exhaust? What do you think of the exhaust here? "GY6-50 Stainless performance exhaust system" about 1/4 page down www.scrappydogscooters.com/139QMB_50cc_Performance.html your suggestions seemed good I just don't want the hassle of making a mounting system hah. When I do order one I will make sure I get a couple different sized main jets. Out of curiosity, how will I know when I have found the right size jet?
The BBK will always be an upgrade I will want to do but I don't think I am capable of doing it yet. It's funny you posted that link to the guide, I had stumbled across it right before seeing your post. I will keep that link for future reference.
I have a few more somewhat random questions. My first is, do you have any tips for getting that pesky variator nut off? I saw the tool which holds the variator in place but it was about $30 I would rather put towards an exhaust now. Second, does the uni filter just install directly to the carb?
Hope I am not annoying with all the questions! Just want to do everything right and make sure my scooter runs better then ever! Thanks again for all the help
That pipe is a great choice (not only because it's the exact same as mine ha ha) but also because it has gotten positive reviews from many other people on this forum. A word of caution though: that exhaust is the exact same kit as the one I bought on Ebay (noticeably more expensive if bought from Scrappy) and there's a thread on this forum saying that it likewise does NOT include the support hardware. More specifically, you CAN install it without that piece of hardware, but bumps and shakes from everyday riding will stress the joint between the muffler and pipe, leading to possible shearing and ruining of your exhaust (that's what happened to the guy who posted that thread).
To be totally honest, upgrading the exhaust by itself didn't show any noticeable MPH gains for me, maybe 1-2 MPH at the most. Other people and mainly advertisers will tell you that by simply adding a better exhaust, you will go faster. That's not guaranteed to be true because more power does not simply equate to more speed. If you boost the engine without touching the transmission, the increased power and torque will send it shooting right through the powerband. You'll rev really high, but the engine won't be working efficiently and you'll lose acceleration and speed. The transmission must also be tuned to effectively get that power to the ground. Those slider weights will be a godsend for your acceleration and top-end.
To see if the jet size is correct for your setup, you'll need to do something commonly referred to as a "plug chop." Ride at full throttle for a little bit, then shut off the engine and coast to a stop. Then remove the spark plug and take a look. If there are white deposits present, you aren't burning enough gasoline (lean mixture). This can cause the engine to overheat and fail prematurely. If the plug looks black and sooty, you are burning too much gasoline (rich mixture). Running rich does not damage anything, but decreases fuel economy, performance, and can ruin your spark plug if left uncorrected. If the engine has noticeable problems while running, go ahead and look here.
As for that variator nut, an electric impact wrench is ideal. A cheaper alternative would be to brace the drive face (the round disk that has teeth all the way around it) with anything that works (block of wood, screwdriver, whatever) and muscle it off with a ratchet and socket. If you happen to have or are willing to buy a strap wrench, I've heard those have worked for some people as well (used as a brace instead of round-the-garage items). I bought one from O'Reilly's Autoparts, but the damn thing broke when I tried to use it. An impact wrench really is the best option.
Yes, any and all aftermarket filters will clamp right onto the carb. I'm assuming the stock filter on yours right now is a rather large black box that hangs over the CVT cover. The new filter will go on the same place as the beginning of the stock filter.
That is a real bummer about the exhaust but I am happy you told me this prior to ordering! I'm not sure what you necessarily mean by support hardware but is it possible to use the hardware from the stock exhaust? I think I will stick to these upgrades for now and maybe in time look into a nice exhaust system.
That "plug chop" sounds like a pretty easy way to see how my jets are working. Can I perform this stationary? Put my scooter on the stand so the back tire is off the ground and then do the test or do i have to be physically riding?
I considered "jamming" something in my variator so I could get the nut off but I figured that would result in something breaking. I will be purchasing an electric impact wrench instead. I'm sure it will prove useful in other situations.
Thanks for clearing up the filter install. I thought that was where it went but it is always better to be positive. So does the stock filter just sit there now basically doing nothing?
Thanks again! I can't wait to start working on my scooter and see how everything works out
No because there is no support hardware for the stock exhaust (at least for mine anyway...). The stock muffler and pipe are one piece (welded together) instead of two pieces connected by nuts and bolts. That connection creates the weak spot in the performance one.
While technically you can do the plug chop on a stand, you shouldn't for two reasons. One, the gyroscopic force from the spinning wheel at high RPM's will cause the scoot to actually slide across the ground, even if you try to brace it with your foot or something. Ya wouldn't want the wheel to catch on something and send the scoot flying. And two, the engine would not be under load, so the engine will rev higher than if you were riding it. You want a reading that will show WOT (wide-open throttle) conditions with you actually on the scoot.
That stock filter is doing its job, but it's probably not letting in ideal airflow. It will of course have to come off to install the new one. After that, you're free to sell it, keep it for a rainy day, whatever.
I ride 40-42 mph tops (was 45 before I lightened the roller weight, it was worth the better acceleration) on rolling flats no problem with my big ss and an essentially stock 50cc., traffic only backs up behind me on steady and/or steep uphill grades. I definitely would not want to go any faster on this Chinese hunk o plastic with 10 inch wheels though, lol
'08 US Titan 1P57QMJ NCY CVT kit & Teflon intake - 9g sliders - Mikuni fuel pump - pod filter w/ tube - $99 POS exhaust - #114/#38 - blue CDI w/orange spark - bedazzled with LEDs - she goes like a raped ape '08 139QMB - Retired
Good point with the plug chop, definitely do not want a runaway scooter haha.
For the filter I guess I was wondering if it could remain attached to the moped or does it have to be removed when I switch to the new one?
As for saying derestrcting will not do anything, well I am willing to take the chance. Even if I see a very small improvement I will be happy. Hopefully I can get the variator nut off soon though! Thanks again everyone
do you still have the reciept for that impact wrench?? go to the nearest home depot and return that sissy impact wrench....and buy this instead @ autozone or O'reilly -----> www.harborfreight.com/12-volt-1-2-half-inch-emergency-impact-wrench-92349.html this is what i use....it loosens any size bolt,,. very powerful. delivers up to 150 ft. lbs. of torque to power off lug nuts. 11 ft. cord with cigarette lighter plug Reversible--removes and installs lug nuts Includes 11/16'', 3/4'', 13/16'', 7/8'' chrome steel sockets 1/2'' square drive 30-40 blows per minute.
Haha my sissy impact wrench...nice. I may end doing just as you say, just need to try one more time. I am no expert but according to the specs the wrench I have produces 200 ft. lbs. while yours is only 150. Wouldn't yours be the sissy just saying haha. Yours does work though, so I give it credit. We will see how tomorrow goes.
LOL!!! well maybe....yeah, try to fully charge the battery and give it another shot.....you know, the entire mechanism of your "S" impact wrench maybe rated to produce 200ft lbs, BUT the "small" battery doesn't give enough power to it to produce that 200ft lbs to begin with. .....now on the other hand,,,my 12v impact wrench gives out full power,provided you have to turn the car engine on while using the impact wrench....now i can say that my 24 buck impact wrench is more effective than your 99buck impact "wreck"....LOL...just teasin' yah bro!....hope you get that project done. keep us posted.
Ok ok my wrench is no sissy!!! Not even close. I just needed a fully charged battery and it took the nut off with ease!! I guess the 18V and 200 ft lb really is better then the "sissy" 12V 150 ft lb haha
Anyways, I received my parts today...sliders, performance CDI, main jet, and uni filter. Cdi is installed, easy. Sliders are in, not exactly sure if they are positioned correctly. Anyone know how they should be positioned in the variator? I'm in the process of doing the filter and main jet but hit a small glitch. I just noticed my stock air filter has a small hose (which is attached to the hose connecting the filter and carb) which tuns to my exhaust...? So when I replace the filter can I just not worry about this? In other words when the stock air filter comes off is it ok to take this off as well?
I wanna ride so bad! Hope this info made sense and I am glad my BEAST wrench worked
BIG PROBLEMS!!!! My questions in the previous post ^ are still issues, but I now have a bigger one.
I installed the new main jet and put the uni filter on, leaving the stock one on (unattached) until i got an answer to my question. So I put everything together, with all my new parts and started her up. She pretty much started right up and everything seemed perfect...but things don't work that way. Suddenly I heard an awful grinding noise! I immediately shut off the scooter and knew it was coming from the variator. When I put the nut back on I wasn't sure how tight to put it on so of course it was too loose and unscrewed itself. I tightened it up and tried everything again, only to have the exact same results!!! So now I am wondering could I have over tightened? The threading appears fine on both nut and bolt. I added a drop of loctite then put the nut on good and tight! Let it sit for about 10-15 mins and put everything back together. She started right up and managed to idle for a long time with no issues. I decided to go for a test drive and was instantly paranoid. It accelerates amazingly slow! But about 75-100 ft into the ride I heard another grinding noise but it was different. I am lost! The nut is still on and very tight. What was grinding???? Could it be the electric starter gear?
Please Help!! I am quite worried I have done something irreversible and am about to give up. I just wanted to make my little chinese scoot perform better but to my typical luck the exact opposite happens!!
Post by eldertripp on Jun 30, 2011 21:54:37 GMT -5
something aint right take it apart again, what about startin up with the cover off and watch the parts move to see where the noise is Also HELP me I run WOT after cone filter chg and it dies out after a few miles, put on HP CDI, HP coil, big main jet and still did same thing, could it have something to do with the vac lines going to the stock air box. I left them in original place and covered up the old opening for the carb. do ya think its a elec thing or a fuel thing???
Do NOT electric start without the cover... it'll spit that bendix so hard you could kill the drive face and/or the bendix. Believe it or not I have started the engine with a ratchet over the variator nut before. A regular electric drill with a 3/8 adapter and a 17mm socket might work better for you.
It might be the bendix itself or one of the kickstart parts grinding too, in which case no noise will be noticeable with the cover off.
I believe sliders should be installed with the largest flat part towards the inside.
Not sure I understand the question about the hose. There may be a hose from the VALVE COVER to the snorkel on the airbox. You can leave that hose dangling from the valve cover, or you can put a breather on it.
I agree with D-cat, try starting with a drill over the variator nut. See what's going on down there.
As for your performance issues, that's what happens when you go messing with the air filter. I have had problems myself. You'll need to figure out whether you're running too lean or rich and tune the carb accordingly. The stock box doesn't do a bad job, IMO, unless you do extensive mods.
QUESTION FOR 50seesee: are the plans for your muffler support bracket available anywhere? I have the same muffler and need the support.
hi i see u know alot about scooters i have a jonway yy50qt-21 i don't know any thing about them but some did run over me already bent my wheel now i looked on line and tried to get parts but not too good with comp either so i was wondering if u know where to get a front rim for the jonway yy50qt-21 ;D
Thanks for all the replies. Things are not getting much better here. I decided to take the uni filter off and reinstall the stock main jet. This will probably be temporary, just eliminating some variables to figure this issue out. Anyways, I attempted to start my scooter again today and now it seems like my electric starter gear (not sure if that's the technical term) is grinding/not starting my moped. It sounds like its not doing anything, just spinning in there. So i took that "gear" out figuring I could just kick start it but that didn't work. The kick start would not budge. So I took it all apart again, put the electric starter back in and fixed the kick starter so it moved (i say fixed but I don't think it really is). Tried to start it using the electric but I made an awful grinding noise. I then tried the kick starter, which pushed down (not smoothly) then got stuck facing perpendicular to the ground. I took everything apart and that's where I am now.
So my questions: What is happening!? Why is my electric starter and kick starter both not working? Somewhat random, should it be easy to spin the variator/belt or take a little bit of force? If I were to start my scoot with a wrench, how do I do that? Put the wrench on the variator nut then what?
Thanks again for the help! I really want to get my scooter running and in working condition. I hate not being able to ride it let alone have it broken.
Btw I put the sliders in with the flattest part (no angles) on the bottom. Hope that is right
no need to derestrict...a 50cc scoot derestricts itself automatically...you can not ride faster than 35mph....otherwise vibration kicks in..
Luke that's really not entirly accurate.. My little scoot does 45 before vibration starts, the vibration comes from unbalanced tires, and worn out motor mounts. And with the upgrade i get up to 50 under the right conditions.. I also know of 50 cc TaoTao scooters that give my 72 a good run for it's money... The guy makes 45, yes he's pushing his engine too hard but he still gets the speed and has never mentioned any vibration..
P.S. the 45 mph I'm talking about is a true gps verified speed.
3x 8 gram and 3x 8.5 Dr Pulley sliders. LED tail and turn signals Bando Drive Belt. And many other mods to numerous to mention.
I fixed everything! I got my scooter running and just took it for a test drive, I must say things have turned around. I took a short ride, which I do quite often, to see if I could feel any differences in the scoot. The first hill I hit was a pretty big one which I normally climb at about 20 mph to a rare 30mph. I did it this time at about 30-35mph only hitting 30 when I was practically at the top. The next hill isn't too steep, just really long and a constant incline. I was always at 30mph on that one before and this time I was doing about 35-37mph and I felt as though the scooter was still speeding up when I reached the top. And finally the last set of hills were really long and fairly steep. I did those at about 35mph which was extremely surprising. As for my flat ground top speed, well it seemed about the same but maybe a little faster at some spots. It was sort of weird because my scooter seemed quieter but was running better. The upgrades I have on it now are a performance CDI and a set of 5g sliders. I have not put the uni filter on yet and I am not sure I will. In the near future I plan on buying a set of 6g sliders to see which perform better or maybe even alternate 5g, 6g, 5g and so on. Also, my speed readings are just based on the on-board speedo so I know they are inaccurate by about 5mph. They are still faster then before though hah. Thanks again to everyone for all the help
wereed: HOw can I start a thread?
Jun 1, 2013 10:55:49 GMT -5
wereed: or respond to a thread I started three years ago...
Jun 1, 2013 10:56:07 GMT -5
marklorenzi: I just bought one of the Fleetwoods. They look like a clone of the Honda XRM's they sell overseas. It is in transit now and I should get it this week. I will try to post my experience here. Call me the guinea pig hahaha.
Jun 2, 2013 20:29:11 GMT -5
flyangler: wereed, this forum is read only the new forum is on the banner above. Dan
Jun 5, 2013 7:35:29 GMT -5
silkyg1973: can someone please tell me how to post
Jun 10, 2013 12:08:46 GMT -5