Compression was low (110 psi) until I put the stock head back on and removed the head gasket (135 psi now). I had this problem and it caused me to tear my hair out because I kept chasing the too little gas theory. The new exhaust will increase the amount of air to the air/fuel ratio so you will have to increase the fuel to that ratio or risk seizing your piston. Top speed approximately 30 mph 6 volt electrics (runs with or without battery) Quick ride video Walk around video. Cone mesh air filters of the 28-29mm variety are plentiful and cheap on eBay or amazon and equally effective. I also read on mopedarmy.com (concerning the Suzuki FA50) that if you went from 20W-40 conventional oil to 10W-30 synthetic oil, you would obtain a 2-4 mph top speed increase. Day 1 - 49cc engine is on my blue qt50. Once kicked to life with the reverse-mounted, left-side kickstart lever, the key is turned to "run" and the engine is able to rev freely. Maybe sooner if you want to be more cautious. The wires from your QT motor are: https://www.mopedarmy.com/w/index.php?title=Yamaha_QT50&oldid=27436. 50 mph. What should you pay for (or sell) a Honda Express? Try a hotter spark plug; So, it was less about performance tuning and more about riding technique. Pull off the battery cover and check out the wiring in the back as well. Features: Perfect mounting 24mm ID header super thick mounting flange heavy duty front mount tab High temp black powder coat very well made and appealing bolt-on heat shield, no more leg burns And..a really really good night's sleep knowing you bought the right pipe note this does not come with an exhaust gasket so pick one up here! Manufactured. Web designers, SEO consultants, etc. Check the header on your exhaust and determine whether it is an "S" shape between the flange and silencer or more of a straight shot between the two. Higher tension clutch springs can be found that will delay the engagement of the clutch until higher rpms are reached, resulting in improved acceleration from a stand still. Expect a top speed gain of at least 10% over stock with this modification. The content producer recommends safe practices when repairing, modifying, and/or performance enhancing mopeds, nopeds, small motorcycles and the like as well as working with power tools, hand tools, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this website. This does not mean that all four stroking is bad. I put 15,000 mile's on it. Yamaha MJ50 Towny two-speed crankcase and right-side swingarm. Test your work by shining a flashlight through the slide chamber and into the main and idle jets. What should you pay for (or sell) a Honda Express? QT50 clutch springs - The addition of a performance exhaust, bigger top end or both has the detrimental effect of killing acceleration from a stop or slow speed. Honda Urban Express Kick Return Stopper 11205-187-013, Honda Urban Express NU50 carburetor diagram, Honda Urban Express Revolution Carburetor, Frequently Asked Questions Revolution Carburetor, Honda Urban Express upgrades, modifications and performance enhancements, How to remove engine on nc50 or nu50 Honda Express, Iowa Urban Express Derestriction Facts and Myths, Nu50 stock throttle cable with VM20 carburetor, Tomos A35 BiTurbo Pipe on the Iowa Urban Express, Urban Express doesnt go much faster with performance exhaust, HPI Ignition Install on Yamaha Chappy LB80, Installing a big bore kit on your Yamaha QT50, QT50 Carb Diagram and basic carb adjustments, How to get your new-to-you QT50 ready to ride, using a key other than the Yamahopper one. QT50s were popular in the late 1970s and 1980s because of their ease of use and maintenance, extremely low gas mileage, and legality in most U.S. states among pre-driving-age teenagers. Damn that was sweet! Do this little by little in combination with PB-Blaster. If the bike doesnt run, make sure you can push down the kick start with ease. I had cyclekeysonline make me a $10 key for it and it worked. Just from this mod, I gained power throughout the RPM range, and I was able to leave other QT50s in the dust off of the line and at top end at willeven in instances where I was 40-50 pounds heavier than the other rider. Controlling the heat produced by a bigger top end and/or a performance exhaust is a common issue with QT50s. Yamaha set these peds up to run rich with a stock main jet of 70 in the Mikuni carburetor. 10. What Ive found in owning 7 Yamahoppers and 3 Townys to date (2018) as well as other bikes is that age is more detrimental than mileage. It has a 15.15 SHA clone carb and currently running a 75 main jet. Now imagine what happens when you put these holes in the back of the airbox. If it doesnt pass all the tests above, subtract as follows: Very rusty gas tank requiring replacement $80-100 deduction; You can still find a rev plate on ebay but under the moniker, "copper base gasket". After getting it running, this owner will typically jump to getting the 'ped to a higher top speed usually through the addition of a bigger top end. 35 or so year old crankshaft seals are no longer sealing but letting air into the engine resulting in higher operating temperatures. Consider it a $39 insurance policy. All this is necessary to avoid seizing your piston as the performance exhaust will have the effect of leaning out your fuel/air mixture. But, I was also riding with a full open throttle. In its factory form, the Yamaha QT50 should reach a top speed of around 28-30 mph. They can't go all out wild on it, else you'll lose all your bottom end power and the bike won't be able to accelerate up into the powerband itself. What you are really experiencing is the engine four stroking as a result of too much fuel in the combustion chamber. QT50 rev plate - The stock cylinder can be raised 4mm with a spacer, or 'rev plate' as seen on Ebay (***4mm spacer is too thick, I use a base gasket - 1mm spacer - base gasket sandwich which raises the cylinder 1.5mm and that should allow the piston to clear the exhaust port fully***). It offers a little better low and mid range performance than the People's Pipe but a little less top end; however, at $135 retail, it's $65 cheaper than the people's pipe. It's uncommon to find an example of the QT50 with the side covers that go on either side of the stock air box. The most outstanding feature of this bike would have to be its final drive which consists of a solid drive shaft (with a torsion spring to dampen the engines vibration) that connects the transmission to a ring and pinion gear set in the rear hub. Want to post in this forum? We are back up and running. If I bump up to an IRC NC 77 tire, Im going to a 70/9014 tire. Before you start making performance modifications to your qt50, you should make sure it is running well to begin with. It appears to have a retarding curve as well." I was bummin' that my 83 QT50 would bog out at 25mph. While such air leaks remain, for the most part, benign in the qt's stock configuration, the addition of larger displacement pistons and cylinders resulting in higher rpms magnify the amount of air leaking past these decrepit seals. The QT50 has the main throttle cable leading to a throttle junction where it separates into two cables. Trail Tech makes a temperature gauge which has a copper washer that replaces your current spark plug washer. Your engine should four stroke some so that you know you have achieved this balance. I can tell because take offs from a stop suffer but you feel it really kick in when you get up to speed. Air filter missing subtract $25-35. Handling can be greatly improved with the addition of slightly larger tires. Install a free-flowing air filter; A stock QT50 has a top speed of 30 mph, and takes a while to reach it. Idling at stop signs doesnt really bring the temperature down much. 278-27114-00) and super glue it to the original stopper so that you have two stacked together. Keep this principle in mind. Check and see if all the lights and horn work. Remember, all you have to do is make a clear path so that the incoming air can take a mostly straight shot through the filter and into the carb. Its like an old house. Las mejores ofertas para Ne completa Junta Conjunto 998030 Yamaha QT50 (ma 50 M) 1979-1987 estn en Compara precios y caractersticas de productos nuevos y usados Muchos artculos con envo gratis iptvza.com. Again, a performance exhaust will call for a larger main jet in the carburetor. Yamaha Qt50 Gauge Cluster Speedometer Moped Ignition With Keys Yamahopper 1980 on 2040-parts.com US $99.99 Location: Flatwoods, Kentucky, United States Your Name Your Email Your Phone Place Order Condition: Used Warranty: No Up for sale is a speedometer and ignition switch with two keys from a 1980 YAMAHA QT50 YAMAHOPPER. Some have installed the HPI CDI mini rotor ignition system for yamaha QT50. Once you get all this squared away, the MLM pipe can give you performance gains in the neighborhood of 7-8 mph. If it goes slower than this, negotiate accordingly. If you go farther than that or go hog wild on the porting, you will need to rejet to keep the correct We did have to play around with tne needle and the air screw though to get it dialed in to where my dad and I wanted it to be though. Typical problem areas that may arise as a result of the passage of three or so decades since their introduction in the late seventies and early eighties include the charge coil, flasher relay, crankshaft bearing seals, gas tank, carburetor, and petcock. Web designers, SEO consultants, etc. A complete PW50 stator can be had for less than $20. Ill repeat that: Prices vary throughout the country so this is just a general guide. Hey, so do I. I'm running a 60cc top end on my QT with the Towny bottom end. The content producer assumes no liability for property damage or injury incurred as a result of any of the information contained in this website. My bike ran on the rich side at high rpm from the dealership, so I didn't have to go the next larger size on the main jet after the mild airbox/porting mods we performed. Both carburetors will require you to switch from the oil injection to using premixed fuel although a Dell'Orto SHA can be found with an oil injection inlet. Eleven is not so good when you dont need it like going slightly downhill. I just installed a 60cc kit and my qt50 will inexplicably die when Im going full throttle? If the bike does run, take it for a test ride. That is just not going to work well. Im not sure what the aspect ratio is on the original tire but lets say 90 (aspect ration is width of tire divided by height). Truth is it is getting too much gas and dying as a result. Re: I got manuals for yall on the net for FREE. Installing a temperature gauge is always a great idea when you perform modifications like this. Ill be interested to see the difference in head temps as compared to stock head. The Yamahopper has an approximate top speed of 30 mph in stock form, and thus can be used for city driving. Or fastest delivery Jan 20 - 24 . Trail Tech offers a 14mm gauge for $39 or so. Youd seize before you got to 40. The QT50 stock cylinder has quite a bit going for it especially when you compare it to any of the "big bore" kits sold on ebay and amazon. Performance modifications will only exaggerate current issues. A larger carburetor may even be a better choice than the stock carburetor with a larger jet. Reducing four stroking through a smaller main jet, more free-flowing air filter or both might get you 1-2 mph more. So I can compare temps between stock head and puch head. Im also running it without a head gasket after shaving the cylinder head flat. It has the exact same wiring and driveshaft as the QT50 and the same 2 speed automatic engine as the Chappy. Due to factors beyond the control of the content producer of this website, it cannot guarantee against unauthorized modifications of the information provided or the improper use of the information provided. Many mistake the low, rough growl as a result of a rev limiter residing in the CDI unit or perhaps elsewhere. You can get Dellorto jets in increments of one so I could experiment with a 64 or 66 main jet. To see our full inventory go to brennys dot com. This is my yamaha qt-50, its a 49.9cc scooter with a top speed of 32mph. I notice sometimes at full throttle it will run rougher, make a different noise, seem to hesitate and check up. Day 5 So I went from 34-35 with next level pipe to 39.7 with circuit pipe. The bigger rear tire is heavier and your qt50 in stock form may not be able to spin it at the same rpms as the original tire. Ive had the stock cylinder slightly over 400 before. Look how wrong you can be. Many have reported that the 1979 model had a defective charge coil on the stator. When I grabbed a handful of throttle when on the pipe (anywhere above ~18mph for mine), that tiny chainsaw motor meant business! The main jet should be your initial focus. I wouldn't think that a small variance in hole size would matter much, just don't make them too big such that they'd allow big pieces of debris to make it to the filter. Or your crankshaft seals are bad and need replaced. The lesson of mopeds and nopeds is to find your next bottleneck and fix it. -DO NOT CONTACT ME. I replaced both crank shaft bearing seals prior to installing the kit. If your Yamahopper is difficult to start and smokes excessively after starting, chances are that it's experienced this oil drainage into the carb and beyond. Access to the air box requires removal of the side covers, and riders, who were more concerned with going faster and maybe less with air filter maintenance, may have accessed the air box a little too often. For every 1 mph below top speed of 30 mph, subtract $15-20; Next step will be to change transmission oil and see if we get any gains or, worse yet, lose any speed. Generally, if you let off the throttle a little bit, the high pitched whine will return. The straighter header will perform better; however, a used QT50 exhaust cannot be had for pennies on ebay and your money may be better spent on a performance exhaust. Perhaps around 10% bigger than stock. If the bike doesnt run dont pay more than $150; New bolts with some anti-seize compound are recommended. In stock configuration, the QT50 will hit about 29-30 mph. But no worries. Be mindful of not completely eliminating all four stroking. Whats the trade off? I used a 65 main jet and it seems to be pretty dialed in. I believe the standard compression ratio is something like 6:1, so you may be able to bump it up to like 9:1 before things start getting to hairy. In 2018, MLM introduced the MLM yamaha QT50 techno EDM circuit pipe. Chances are your tires on your 35 or so year old qt50 are a mess. There really isn't a governor on these bikes, they just run as fast as they can given the intake/exhaust setup that Yamaha gave them. 2 stroke engines are designed to four stroke in certain situations. Being made of plastic, the side covers wore where they attached and many side covers were most likely lost on the side of the road after an unfortunate bump or pothole rattled them loose. Subscribe to: Posts (Atom) Youll think your qt is not getting enough gas because it stalls. Your QT50 is just getting too much gas and oil. The content producer recommends safe practices when repairing, modifying, and/or performance enhancing mopeds, nopeds, small motorcycles and the like as well as working with power tools, hand tools, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this website. 40.1mph. The Mikuni VM18 carb is almost as lethal as nitrous. This leads to hacking into the wiring. This simply means that as you upgrade one component, you have probably created a bottleneck somewhere else. Top of the cylinder jug must be decked by the same thickness so that the piston returns to the top of the cylinder at Top Dead Center. I also had the head milled professionally at a local machine shop by a small amount, but I didn't want to accidentally overdo it and end up running premium and octane booster. I'll make videos of each top speed run and post them here. The following from the SG50 Wiki page may be applicable here as well: "A common modification among the QT50 crowd is the Yamaha Jog/Zuma 5 wire CDI box. The immediate goal is to break 40 and then shoot for 45 mph. To see our full inventory go to brennys dot com. Took a ride with current setup as listed above. Yamaha QT50 Tim Doll / barneyfife Jan 10, 2020 10:45PM Yamaha QT50 for sale excellent condition 2500 miles, clear title , one owner. I will post a better video when its not so windy. -DO NOT CONTACT ME. You should see a large circle of light through the main jet and a much smaller circle of light through the idle jet. Maybe Ill shoot for Pete Roses number. Future topics to be covered: 6. After the main jet, dial in the jet needle. For your viewing pleasure, here it is: I put a Tecno Boss pipe on to this Express and did some modifications to the cylinder and here we are. New tires may be in store for you as well. Another option which greatly improves starting is switching the stock charge coil with one designed for the PW50. Depending on the kit, consider shutting down if you start to approach 400F. Chances are you still wont get a good idea of how rusty the tank is even by doing this. Im looking at a QT50 that Im thinking about buying. Also went down to 14 tire. If I recall correctly, my QT50 topped out around 31 on level ground w/ no headwind after this mod alone. Front tire was a bit wobbly at. I got manuals for yall on the net for FREE! In short, here's what I did to my QT50 to make it a little bit peppier. A temperature gauge is mission critical to keeping your piston from soft seizing. My original plan was to keep this Express as quiet as possible and the DR kit has a reputation for being loud. Ill continue to work with it before trying a different exhaust. These bikes like most Japanese bikes of the time came with excellent finishes in both the paint and chrome, though the plastic parts on many of these have deteriorated over the years. Of course, youll need to change your main jet to a bigger one to compensate for the additional air (you need to keep your fuel/air ratio similar if you add more air, you need to add more fuel). 41.6mph. Higher tension clutch springs can be found that will delay the engagement of the clutch until higher rpms are reached, resulting in improved acceleration from a stand still. Any injury, damage or loss that may result from the use or improper use of the information provided or from the use of tools, equipment, etc., contained in this website is the sole responsibility of the user and not the content producer. You more than likely over-jetted. I never ran into overheating problems, nor did I ever have a mechanical breakdown because I kept up on its maintenence. It's simple, maintenance-free shaft-drive contained in the single-sided swingarm eliminates chain maintenance, safety and wear concerns as well as weather wear factors and contributes to the durability and ease of use of these tiny motorbikes. 3. In addition 60cc top ends are prevalent on ebay and amazon. Because I opened up the reed block slightly, a 2.5 increase in jet size is significant. Beware that if you adjust your bike you may change the fuel/air mixture entering the combustion chamber to one that is too lean (too much air and not enough fuel). clutch yamaha qt50 hand yamaha pw50 yamaha mt 15 singapore pee wee yamaha pw50 yamaha qt50 wiring diagram yamaha qt50 top speed. Kevlar brake pads and stiffer clutch springs! Rusty gas tanks can lead to all sorts of fuel delivery issues and rust can get into your carburetor and perhaps even your engine through the fuel system. Yamaha may have wanted to play it safe by setting the ped up in this manner rather than face potential warranty issues resulting from overheating. So if my qt50 can spin the taller tire at the same revolutions per minute my speed should increase. This setup requires no maintenance and has the safety feature of lacking any exposed moving parts such as a chain that could catch one's clothing. Top speed without an extended full throttle run of 34-35. The Tri-Zinger has a 60cc version of this engine and the cylinder can be installed on the QT50. Plastic parts may be the most difficult of all as they did not age well if left in the elements. Web designers, SEO consultants, etc. No such rev limiter exists. The 50 in the name is derived from the 50cc engine displacement. Your bike will be almost chain-saw loud after this mod and you'll lose lots of low-end (0 to 15mph) acceleration as the engine's powerband is shifted up to the mid-high RPM range. Day 6 I let her eat today. If it passes all the tests above, is in mint condition, and has title, I wouldnt pay more than $650. The original tire size on the qt50 is 2.25 wide by 14 in diameter. Engine failure is imminent. Having fun on the Yamaha qt50 AboutPressCopyrightContact. Couldve easily seized it with an extended full throttle run. This is not a moped since it doesnt have pedals. I ordered a puch 40mm head. Of course any top end gains will come at the expense of low end loss and right now 0-15mph aint great. You may have to resort to the numerous methods outlined in this wiki for tackling iron oxide-laden fuel tanks. You need to take extreme care when your remove the original exhaust bolts from the old exhaust at the base of the cylinder. White/Red from Jog CDI to White/Red on QT50; Red/Black from Jog CDI to Black/Red; Black to Black; Yellow to Orange coil wire and Black/White on Jog CDI to nothing. Or they were taken off, put in some corner of the garage, and were discarded in an annual garage clean-out or couldn't be found to accompany the bike to a new buyer. Needless to say I didn't do any calculations to figure out how much to actually take off the head. #29-3208 | Yamaha QT50 (1979-1987) Front Brake Shoes Pk/2 Diameter: 79.3mm Width: 17mm OEM Ref # 27V-W2535-00 USD$ 5 .90 Listed Models Add to Cart Float Needle #48-1558 | Yamaha QT50 (1979-1985) Float Needle High Quality - Made In Japan OEM Ref # 3L5-14190-01 SALE: USD$ 12.00 (USD$ 19 .95) Add to Cart Universal Glas-Pak Insert #009-0317 Take a flashlight and take the lid off the gas tank. I consider myself fortunate as my dad was very knowledgeable about how 2-stroke engines run and what you need to do to make them "breathe" better. Try an 80 or 85 main jet. Also check the foot pegs to see if they are bent. But, I was also riding with a full open throttle. Day 3 I put a bigger pilot jet in the blue Qt. Your main jet is way too big. Swap in a slightly smaller main jet, a less restrictive air filter or both. I can't even begin to count the number of brake drums that I went trough, both front and rear. Ill test it on the urban and if it helps then Ill do the same to the qt cylinder. Tire width goes to 3.15 inches and top speed goes to 32.71 mph. Unfortunately, its fairly common for people to lose the key. I can probably jet higher after getting the piston to clear the ports. I thought the stock exhaust might help in this regard. Next, hold a finger over the spark plug hole and have a friend kick start the bike. Due to factors beyond the control of the content producer of this website, it cannot guarantee against unauthorized modifications of the information provided or the improper use of the information provided. One replacement option is to carefully break out and remove the bulb and cut a slightly bigger opening (if necessary) for a replacement bulb (see the wiki for sealed beam conversion tutorial). Anything goes only rule is keep the 49cc engine. On a large ride, I was able to keep up with the Puch's and Carabela's. Day 2 bumped up the main jet slightly to a 67.5 and it took a bit longer for the engine to get heat soaked. Now my former paperweight had a new lease on life. Chances are those old exhaust bolts are super rusty. Im currently running 10W-40 conventional oil and I think I notice some drag on cold days. Motion Pro Rubber Sleeve (11-0045) 0 # mpn4565891373. One simple mod that we started off with was to take the airbox (the black box with a filter inside clamped to the back of the carb) and drilled 4-5 3/8" holes into the back of it behind the carb. The engine needs more fuel going uphill because it is under a bigger load. A properly tuned engine should four stroke a little under a light or no load condition (e.g., going downhill). I put perhaps 15,000 miles on this bike (the plastic speedo/odometer housing in the front hub failed after about 9,000 miles due to these speed mods), and I cannot stress enough of the importance of taking care of your air filter and making sure you keep that oil reservoir full. Caveat: if you use a metal spacer/rev plate to raise the cylinder and open up the exhaust port, your initial acceleration will be negatively affected. Worth it? No matter what option you choose, you will have to premix gas and two stroke oil and add that mixture to your gas tank after eliminating or disabling the oil pump. Does the owner have title? Get an aftermarket mesh air filter. Puch head arrives Monday. Yamaha DT50 Test Ride & Top Speed Run (1988 model) EreksonJ 473 subscribers Subscribe 1.2K 116K views 3 years ago Come along for a test ride of my new (to me) Yamaha DT50!