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Post by cybie257 on May 21, 2008 0:03:45 GMT -5
OK, so I have MAUI-50st with the 82cc (autotech) full upgrade kit and I put in a #80 jet. Everything else is stock (intake, cdi, air filter, etc. On my way to work (25miles), I can average about 52MPH at about 90-95% throttle. On my way back from work, or anytime after about noon time, i can only achieve about 45MPH at about 65-70% throttle. Up to 45MPH, I can full throttle it to get up to speed without any issues. But, when I hit 43+MPH, I have to start letting off the throttle in order to maintain a speed without hesitation, or cutting out. It'll run at 45MPH all day long without issues, but again, as long as I don't exceed about 70% throttle. I get about 90MPG with this setup, so I'm not sure where to go as it seems to be running very efficient. Is it possible that the warm air during the day doesn't allow it to pull enough fuel in, meaning I need to increase the jet size? I've already concluded that the fuel delivery is fine because up to 43MPH, and long hill climbs, I can full throttle all day long without running out of fuel (in the carb). When I speak of warm air, I live near Salem, OR and that's talking above 60 degrees and usually with some sun. On another hand, I am thinking about upping the carb to the 24mm 150cc part. So, is the 82cc head already sized for the larger intake? Or will I need to modify it? 90MPG, I wanna get this puppy running tip-top. Thanks - Cybie
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Post by Enviromoto on May 21, 2008 8:56:55 GMT -5
Stock setups use a #85 main jet so when you used a #80 you took fuel away from a engine that requires more. You need to run atleast a #90 (I recomend a #92) or your going to burn a hole in your pistion.
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Post by cybie257 on May 21, 2008 14:36:50 GMT -5
Stock setups use a #85 main jet so when you used a #80 you took fuel away from a engine that requires more. You need to run atleast a #90 (I recomend a #92) or your going to burn a hole in your pistion. Interesting. I found a #70 in my stock bike. hmmm. But, yeah, I was thinking bigger jet, just wanted some feedback in case there was something else I could do. Thanks for the input as I will give that a try. Anyone else have any other ideas? Open to whatever -Cybie
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Post by medman1952 on May 24, 2008 14:55:18 GMT -5
Runs better when it is cooler, might be because of air density. Check for any crack in a hose or plastic that might be causing a vacuum leak.
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Post by cybie257 on Jun 1, 2008 0:51:46 GMT -5
Checked all those as a first shot and found nothing. I know from reading in the past that some of the stock hoses don't last very long. Although, from what I've read and seen, not much of the stock items seem to last people very long, but with over 2500KM (1600+ Miles), the only things that needed to be changed are oil, battery, fuel sending unit. The fuel sending unit became a problem after being filled up and the float came off the rod. I think it was inadvertently shoved off by the pump nozzle .. But, all is good except this hesitation problem after 45MPH which I am going to order a bigger Jet. Will post results when that happens. $4.09/gal, rain or shine, this baby's getting ridden to work, getting 90MPG with the 82cc Upgrade. -Cybie
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Post by kaczor on Jul 1, 2008 15:12:44 GMT -5
But, when I hit 43+MPH, I have to start letting off the throttle in order to maintain a speed without hesitation, or cutting out. It'll run at 45MPH all day long without issues, but again, as long as I don't exceed about 70% throttle. The only two times I've seen this behavior on my scooter is when I was running lean at WOT and I had to put in a larger main jet. Now granted, if you have an issue with a vacuum leak, it will behave similarly, so do check your entire intake path from the carb to the engine paying special attention to the plastic spacer between the intake manifold and the engine! Those tend to crack very easily.
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Post by rallyrrr on Jul 25, 2008 3:16:40 GMT -5
I bought a cheap chinese scooter in '03. Name brand was Tuohe. It was qmb139 powered. Bought it new. Seller clamed it would do 45mph. It would only do maybe 38? I set about trying to remedy this as inexpensely as possible. As far as power is concerned minimizing flow restrictions into and out of the engine, proper jetting and a Denso 0.4mm tip irridium plug got me to 45 and with proper gearing (upgear) would have gotten me to 50. I would estimate I gained approximately 40-50% in power by improving high speed airflow. My modifications included: Size-matching exhaust port/headpipe junction and smoothing imperfections on either side. Sawing muffler apart, removing baffles and rewelding. A small round steel disc was tack-welded about 3/8" immediately behind muffler exit to break up and spread out exhaust pulse. Unmuffled 50s are extremely piercing to the ear and I had to take it easy around the cops. Filing down cv carb brass butterfly pivot spindle and butterfly retaining screw so that around 2-2 1/2mm remains on either sid of the butterfly. Leading edge of butterfly when fully open was also tapered slightly on non-resting(when closed) side to prevent as much turbulance as possible in the airstream as it parted above and below the butterfly at WOT. This really made a difference. Probably increased flow area by 10+%. The smaller the carb bore the more effect this technique has. Polished inside of intake manifold and matched to head port. Adapted K&N automotive valve cover vent breather(was just like oiled cotten air filter) to carb for air filter. Cost around $13.00. Can't remember adaption details but may have involved metal vacuum cleaner suction nozzle glue and pvc pipe/coupling. Irridium plug (these things do provide advantage through consistent firing under a wide range of conditions). Main jet was drilled progressively with plug-reads and seat-of-pants evaluations made as to power and delivery thereof. At point of performance drop-off jet was filled with electronics solder and redrilled to next to last size. Transmission modifications: Ground 1mm from variator spacer length very carefully while constantly rotating spacer for even material removal. Chamfered(beveled) remaining sharp edge slightly. This lets belt ride out slightly higher on vees for slightly higher-speed gearing. Inner surface of variator can be marked with a magic marker to see how far out belt is riding. If obtainable, 1mm diameter larger roller weights would help here too. I tried drilling my roller weights to reduce weight but botched the job and wound up having to order weights from the U.K.(only place I could find them at the time) to get the weight of 4.2g I desired. Subsequently I have been able to successfully drill rollers for my '02 Derbi Atlantis reducing the weight from 7 to 4.5 grams. Hint. Use plenty of lube while drilling. Removed weight in identical locations from the three clutch shoes by drilling and grinding(same effect as installing stronger springs) and final matching of weights for higher rpm engagement and quicker take-offs. Note. Removing the weight the fartherest away from the pivot has the most effect. Installed home made bushing behind torque-driver spring(can't remember what I used) to help hold up RPM on acceleration and up hills. Scoot would now do 45-47MPH @10,700RPM. I am confident that 50MPH would have been easily obtainable with an up-gear kit. Take-off would jump you ahead of traffic at lights easy. These are very inexpensive techniques that yield substantial results. The tools are really the most expense, but once you have them you can work on any number of scooters. Word of caution. These things break piston rings when rpms get in the mid elevens or so(and a little birdie didn't tell me). So watch that tach going downhills. Another reason for upgearing. Positive note. This particular scooter with trailing-link (or is it leading?) front suspension and skinny 10" tires would lay into a curve fostering a lot more rider confidence than my telescopic-forked, fat, 12 inch-tired European Derbi. The Tuohe's drum brakes. Not so good. Nice things to have when scooter tuning: Electric impact wrench. 120 VAC model for the power. About $30-40. For weighing roller weights, a simple, hand-held letter scale. Harbor Freight has a digital scale that may be even better. On sale about $13.00. Suggest www.drillbitcity.com. Great selection of inexpensive good quality twist bits. The ones at Harbor Freight, if you find one in their odd packaged assortments to suit your .purposes, are very brittle and break very easy. 0.001" digital or dial calipers. 0-6"range. An Installed tachometer. Northern Tools. Small engine section. EMC digital with hour meter. About $45.00. Not very responsive, but who's shifting gears anyway? Ha. Ha. I installed one of these inside the dash in the available plastic to the right of the speedometer under the "glass" in my present Derbi. Had to install a tiny incadescent lamp inside the tach for night time illumination. That was a bitch. I just glued it on the China job with no illumination. Sewing needles can be used to drill jets. Cut them off square with a pair of sharp diagonal wire cutters and carefully deburr the corners leaving the full width. Clamp it long ways in a pair of vice-grips and spin the jet on the needle by hand. Not real fast and you have to make small-change cuts. Use the calipers to measure needle diameters. Tips for night riding: Install the brightest headlamp bulbs your generator will handle. Remove some of your speedometer illumination lamps so that you can barely read the speedometer and obscure your high beam indicator if it is glaring in your eyes. You can see down the road so much better and if you've hopped up your scoot you need all the help you can get. Happy scooting and may your asphalt abrasions be mild to non-existant. Reg
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Post by Enviromoto on Jul 30, 2008 12:27:49 GMT -5
Update:
In Indianapolis here is what worked best for my 72cc upgrade.
Stock Head Stock exhaust 72cc big bore kit 85 main jet 38 pilot jet 2 1/2 turns fuel mix 8.0 Dr pully slider weights UNI free flow intake
48 mph top speed 40 in 6 seconds 45 up steep grades Rider weight 270
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Post by lectric on Jul 30, 2008 19:07:47 GMT -5
Hi, I just bought a new scooter (2008 Bashan "Motobravo" 50cc), and looking to upgrade the performance as much as possible. Mine has pretty slow acceleration, but seems to do 40 mph easily, once it gets moving, and seems to be improving as the engine breaks in. I have a couple of questions, and some clarification, if someone doesn't mind educating a noob:
1. The carb kits that kaczor is talking about at the top of this thread - can I use any of these carb kits on my 50cc scooter? (sort of like overclocking a computer), or do I need to use the one that matches my engine size?
2. Mine comes with a cheap foam air filter. Has anyone tried replacing (or making) a higher-quality air filter, for better breathing? Does anyone know if these Bashan bikes match any higher-quality OEM parts maker (like Vespa or others)?
3. Also, some of the other posts mentioned removing washers in the exhaust pipe and baffles in the air filter housing.... Is there a post somewhere with a step-by-step? Pictures are always helpful for the first-timer....
4. Is there (or can there be) a single post with all of the tricks for maxing performance on these little scooters?
Thanks!!!!! js
2008 Bashan "Motobravo" 50cc scooter.
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Post by stiks on Aug 2, 2008 17:31:47 GMT -5
if you read through the who;e thread you will see
1: dont know havn't looked at them. 2: yes you can get a regular free flow filter like a uni-filter or other cone type paper filter but you will need to upjet your carb (put a larger jet in the fuel bowl) or you will run it to lean and burn the motor up 3 there are some here but i don't know exactly what to do a sesrch for.. mainly though it is taking parts off and looking for the stuff.. plastic washer between variator plates, rubber piece behind foam filter in airbox, washer tack welded to the header pipe of the exhaust.. variator washer cut and remove (or diassemble variator and remove but first method is easier), open airbox and pull rubber piece out, remove exhaust and if washer is there use a dremel or other small rotory grinder and remove it.. 4 your in it for the most.. read all threads from 1 to current and you will find most of what you need..
your 50 is doing pretty good for stock actually. just keep working on breaking it in so you have a baseline to know where you get improvement when you start tinkering. when my WF was still stock it did 40 after breakin then i had to tinker to get any more. best bet to improve accel up to speed would be changing roller weights though more then other things..
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Post by pantinor on Aug 7, 2008 17:12:40 GMT -5
Any issues with the starter when you upgrade to the 82cc cylinder and head kit with and leave the stock carb on and stock exhaust?
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Post by rw58 on Aug 10, 2008 21:38:12 GMT -5
I was able to achieve good acceleration and top end in my Roketa with a 50cc engine with low cost upgrades also. This is what I did. Rejeted the carb from a #79 main jet to a #80. Tried others, but no increase in performance was detected. Only more fuel consumption. Changed the variator to a high performance variator using 3 - 8.5g roller weights. Changed the belt to a gates power link. 0 - 30MPH is quick. Acceleration is constant with power to climb. 46 to 47MPH on the flats, gets there quick. I weigh 220 and it still moves out great. I get 224mpg with this set up. Also, a wind shield is essential. I don't get this kind of performance without it. Top end drops and fuel mileage drops without it. The air box is stock, and there is no big bore kit. I use the 8.5g roller weights because I haven't received my 4.5g weights yet. I think my top end will increase slightly with the 4.5s. I had a top end speed of 49-50MPH with the stock variator and a combination of 6.5 and 5.0 roller weights. Acceleration sucked. The only problem with the setup with the high performance variator is that the diameter had to be machined down to 40mm so the starter drive teeth would not grind into the variator. I'm still fine tuning with the weights.
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Post by rallyrrr on Aug 11, 2008 11:21:23 GMT -5
Wow rw58. You are truly a magician. 224 mpg. You need to check with Guinness. That might be a world record. More top speed with a windshield and lighter roller weights? Mystifying. Surely you must have been testing with about a 100 mph tail wind.
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Post by rw58 on Aug 11, 2008 17:33:36 GMT -5
Darn! I was trying to get back to this post to fix that and another arror I made. But, you where too quick. Not only won't my scooter do 224mpg, I didn't machine my variator to 40mm. I met to say 90mm. Please don't try to machine it to 40mm. You won't like what you see. Anyway, 120mpg, give or take a few depending how much dinking around I do.
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Post by Karl on Aug 11, 2008 17:38:03 GMT -5
Darn! I was trying to get back to this post to fix that and another arror I made. But, you where too quick. Not only won't my scooter do 224mpg, I didn't machine my variator to 40mm. I met to say 90mm. Please don't try to machine it to 40mm. You won't like what you see. Anyway, 120mpg, give or take a few depending how much dinking around I do. rw, I don't know how much "dinking" around you do, but in Texas it can get you thrown in jail! ;D
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Post by rw58 on Aug 11, 2008 18:39:56 GMT -5
I'll never use that word again on here.
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Post by 04apriliaxrally50 on Aug 12, 2008 12:35:54 GMT -5
nice
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Post by lavoyermn on Sept 25, 2008 0:07:52 GMT -5
Very Good Post In Minnesota It could cost you very easy over $1000.00 for going over 30mph with a 50cc with out the proper paper work and training and testing
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Post by tonytech81 on Oct 11, 2008 17:22:33 GMT -5
HELLO WELL FOR START I GO A TANK URBAN SPORTY 50CC RUNS GOOD I BEEN DOING SOME MODIFICATION ON IT SO FAR I REDRILL STOCK MUFLER ELIMANATE PETCOOK FUEL PUMP 2 A GRAVETY DOWN FEED WITH MANUAL SHUT OFF VALVE TO INCREASE GAS FLOW ALSO PUT UNI FREE FLOW FILTER WHEN T 2 DEALER AND ORTHER IRIDIUM SPARK PLUG AND BIGERT JETS SHOULD HAVE THEM WENESDAY ALSO NEED 2 ORTHER ROLLERS BUT DONT KNOW HOW MANY GRAMS MYNE AR I AM GETTING ABOUT 32 TO 35 ON FLAT 25 UP HILL AND 45 DOWN NEED HELP ON ROLLER WEIGTHS TANKS
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Post by tonytech81 on Oct 11, 2008 17:26:22 GMT -5
ALSO IS MORE LOUDER SENS I REDRILL MUFLER AND PUT UNIFILTER BUT NEED 2 PUT JETS AND CHANGE MY WEIGTHS THAT THE ONLY 2 THINGS LEFT ON MY LIST
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Post by Enviromoto on Oct 18, 2008 13:37:19 GMT -5
#88 - #95 main jet, 5.5g rollers or sliders. STOP YELLING AT US!
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Post by gabe502000 on Dec 24, 2008 21:26:23 GMT -5
I,ve got a Yamaha C3 that has Electronic Fuel injection. So, no carburetor to try and figure out the mixture on. I found a company in Iowa, Ks Power <Kspoweronline.com> that has modified a Dr.Pulley Variator to work on my scoot. I just got my parts: Dr.Pulley variator, D-P 3gr sliders, A new Gates drive belt, A stouter clutch spring, And the next tallest rear tire that will fit my rim and not rub anywhere. It's going to be next week, I'm going to bounce all of this off of my Yammy dealer's Service Mgr. (He's a nice guy, does good work, My scoot was the first C3 they'd derestricted, And if they do the work I might keep my warrenty + extended warrenty intact! ;D I'm going to use my lady's new GPS tomorrow to see exactly how fast I'm running stock + derestricted and I'll Let you know how my project is proceeding! Gabe
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Post by kyfriedscooter on Dec 29, 2008 22:33:22 GMT -5
Hit 52mph confirmed GPS on flat road today with no wind. I've got a Roketa Maui-50-GL, racing CDI & plug wire, iridium plug, #85 jet, K&N style cone air filter and using regular gas. Stock exhaust.
It's running a little louder than I though it would be, but it is kicking ass. I might go for a clutch springs change when the weather breaks here in Kentucky, but I'm satisfied so far and might leave it as-is. Good acceleration and gets up to speed fast.
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Post by indy50 on Jan 29, 2009 23:03:47 GMT -5
Hit 52mph confirmed GPS on flat road today with no wind. I've got a Roketa Maui-50-GL, racing CDI & plug wire, iridium plug, #85 jet, K&N style cone air filter and using regular gas. Stock exhaust. It's running a little louder than I though it would be, but it is kicking ass. I might go for a clutch springs change when the weather breaks here in Kentucky, but I'm satisfied so far and might leave it as-is. Good acceleration and gets up to speed fast. So, how much do you weigh, about 3 lbs? J/K Pretty impressive considering what little mods you've done.
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Post by rallyrrr on Jan 30, 2009 0:00:20 GMT -5
Hit 52mph confirmed GPS on flat road today with no wind. I've got a Roketa Maui-50-GL, racing CDI & plug wire, iridium plug, #85 jet, K&N style cone air filter and using regular gas. Stock exhaust. It's running a little louder than I though it would be, but it is kicking ass. I might go for a clutch springs change when the weather breaks here in Kentucky, but I'm satisfied so far and might leave it as-is. Good acceleration and gets up to speed fast. Don't be surprised if when the weather warms up your scooter doesn't run quite so well. You're currently getting a very dense and slightly lean mixture into your engine due to the cold air. These are conditions for maximum power from your scooter. Humid air also dogs out performance cause water ain't oxygen.
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Post by Scootless Wonder on Jan 30, 2009 9:58:42 GMT -5
Humid air also dogs out performance cause water ain't oxygen. Not only that but water also doesn't compress. Now I dunno if maybe I got the special needs scooter or if it just has super retard strength but I've been up to 45 MPH rather frequently and I've done nothing to it. I would think a few minor tweaks would put my into the 50 MPH club fairly easily. But then again I'm not using a GPS to gauge speed. Maybe I should talk to a local policeman and get him to clock me to test the speedo. Either way at WOT I can achieve 45 MPH if I have enough time and space. Of course there's a fine if I get caught doing that so I don't try to very often and I'm sure the warm air of the summer will knock my numbers down but while the cold is here I'll enjoy it ;D
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Post by rallyrrr on Jan 30, 2009 15:12:39 GMT -5
There you go.
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Post by indy50 on Jan 30, 2009 16:07:24 GMT -5
Your average chinometer is about as reliable as a $2 watch. Find ya one of those DOT signs that tellya how fast yer goin, if ya dont have acess to a gps.
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eel
Junior Dawg
Posts: 11
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Post by eel on Jan 31, 2009 19:51:40 GMT -5
Riker, I have the kitako 95cc kit with the big valve head. I did some port work to match the 20mm throttle bore size to the inlet manifold and same to the exhaust port to suit the pipe.
It'll do 50 but that is a byproduct of the bottom end hit.
Imho, the fun in these little scoots is in acceleration. If I wanted to do 150mph, I would be on a kawi zr14 or something that actually has the brakes and dynamics to deal with these speeds safely.
On the honda today, the variator is a restriction device so has to be binned straight away. Kitako makes a great one that has ramps that go all the way to the edge for decent top end.
I made 5.2g rollers after much testing. I want to try the dr pulley ones but they are hard to find in Australia and I would have to buy 24 heavy ones so I can modify them to tune the variator.
I had the 95 bore kit with the standard head and it was gay. Even with a decent port job it just couldn't flow enough wind. The kitako big valve head was even factory hand ground to match the seats to the head casting! good quality. I wouldn't bother to pull the valves on the next one I do. The only issue I have is that I can feel the starter motors pain with the increased compression and capacity. Also, installing the 10mm wrist pin circlips supplied is better suited to someone with smaller hands, more patience and a much more limited vocabulary of cuss words. My three yr old daughters kindy teacher is in for an interesting time.
On carb tuning, the keihin CV carb has metering issues but I don't want to modify the under seat storage bucket to run a flat or "D" slide carb. I've found that the fatter you go, the more power it makes. I'm running a 105 main at the moment and it hits pretty hard. This is with the standard airbox with Homer Simpson "speed holes" added.
In short, a quality big bore kit with a big valve head, bigger carb and pipe is definately worth the cost and is alot of fun to install and diall in. I have done a few for mates unported but it's definately worth spending an hour or so with a die grinder to match the inlet manifold to the carb and head and the exhaust to the exhaust port.
Now, you have to lean forewards off the lights to keep the front wheel down and it's soooo satisfying dusting Harley riders!!!!
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eel
Junior Dawg
Posts: 11
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Post by eel on Jan 31, 2009 20:07:50 GMT -5
Oh yeah, I'm a jetski mechanic and have found that Keihin jetski jets fit and also mikuni low speed jets work as scooter keihin CV carb high speed jets. So if you live near a jetski shop, you have access to jets. Also, most jetski dudes are closet hoons so would probably be interested in a scooter persons hot up project. If you were nice to them (supply the occasional beer) they would probably exchange jets until you were dialled in.
This is my rough tuning guide that seems to work with my setups.
Do a decent full throttle run then shut the throttle, let it coast for a bit on trailing throttle then nail it. If it has one rich "pop" it's on the money for traffic light drags.
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