Many have had better luck with the slightly smaller 67.5 main jet. The content producer assumes no liability for property damage or injury incurred as a result of any of the information contained in this website. Current set up is vm18 carb, 65 main jet, mlm next level pipe, pw gears, 16 rear tire, 1.0mm spacer. Yeah, Im an oil freak. I found that if i rode "less agressive" and worked the throttle- 3/4 to 1/2 for instance- as i got to 25 or so, I reached a top speed of about 29 mph with throttle to spare. So it has a 67.5 main jet in it now but a 70 jet is way too rich. 2 stroke engines are designed to four stroke in certain situations. 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. Another culprit in QT50 excessive four stroking is the oil pump. Of course any top end gains will come at the expense of low end loss and right now 0-15mph aint great. Prices vary throughout the country. A too lean mixture can cause serious engine damage. My Honda Express at the time of purchase. Another option is to obtain a headlight for a Honda C70. Want to post in this forum? Any 28 or 29mm air filter is most likely an improvement over the stock air box (although many have resorted to drilling speed holes into the stock air box). Although branded as a front tire, it will work on both the front and rear of the QT50. The wires from your QT motor are: https://www.mopedarmy.com/w/index.php?title=Yamaha_QT50&oldid=27436. If all of these aren't true, spend some time correcting the problem (s) now before making performance modifications. It also leads to using a key other than the Yamahopper one. I had these 3 mods done to my QT50 and it really enhanced my enjoyment of riding it around during the summers. Maybe sooner if you want to be more cautious. Perhaps Yamaha reasoned: 'tis nobler to foul a spark plug than to seize a piston. Overheating and piston seizure are traps for the unwary. Or you can find a hose or fuel line that offers a compromise between the different sizes of the oil injection inlet and outlet ports and connect the two to continuously cycle a small amount of oil through the pump while running premix in the fuel tank. Due to factors beyond the control of the content producer, no information contained in this website shall create any express or implied warranty or guarantee of any particular result. Install an MLM peoples sidebleed exhaust. Youd seize before you got to 40. In late 2017, MLM came out with the QT50 Next Level Stock Pipe. Engine failure is imminent. This leads to hacking into the wiring. Now my former paperweight had a new lease on life. Ill continue to work with it before trying a different exhaust. Call 563-359-7222. Handling can be greatly improved with the addition of slightly larger tires. Puch head arrives Monday. And cylinder got sanded down after 1.5mm of spacers added to open up all ports fully except intake at BDC. 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. Eliminate your oil pump and just use pre-mixed gas/oil at a specific ratio (50:1 or so); This is my yamaha qt-50, its a 49.9cc scooter with a top speed of 32mph. I never ran into overheating problems, nor did I ever have a mechanical breakdown because I kept up on its maintenence. Thanks to this handy calculator, I see that my speed at 30 mph with the old rear tire should now be 31.53 mph. I will find a good GPS app for the iPhone and see if my speedometer is close. Keep this principle in mind. Manufactured. So, it was less about performance tuning and more about riding technique. This is the trade off for more top speed. 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. Crankshaft bearing seal replacement on mj50, qt50 and pw50. 5. Another option is to remove the plastic gear from the oil pump and re-install the gearless pump. 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. Unlike a scooter, the QT50 has no fairing, sports footpegs rather than footboards, and its two-stroke reed valve engine is slung beneath the monotube frame motorcycle-style. 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. Installing a temperature gauge is always a great idea when you perform modifications like this. But, I was also riding with a full open throttle. Sharing an entire drive train with a fairly current children's dirt bike means most things can be had readily from your local Yamaha dealer. Or fastest delivery Jan 20 - 24 . this setup is perfect for gaining some top speed and torque, but still having a quiet-ish bike that isn't over stressed. Most of the parts for the QT50 are still available from Yamaha dealers. The rear brakes tend to be weak on this bike. Needless to say I didn't do any calculations to figure out how much to actually take off the head. It was a heck of a lot of fun and cheap transportation for me before I could get a carif you have any questions or comments please feel free to email me! Be mindful of not completely eliminating all four stroking. I solved it by going from a 102.5 jet to an 87 and finally to an 85 main jet. Another cooling strategy is to employ a colder spark plug. Day 1 49cc engine is on my blue qt50. When you increase top speed, make sure to upgrade your brakes with new pads, new cables, lube old cables, etc. The Dell'Orto SHA 15.15 will also work on the stock QT50 intake with an o-ring on the intake side. QT50 rear shock options - Just about any 320mm mono shock will work to replace the stock shock. Ill make videos of each top speed run and post them here. Re: I got manuals for yall on the net for FREE. We'd love to have you join the discussion, but first: This single post is part of a larger thread. 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. #4 -DO NOT CONTACT ME. Many have reported that the 1979 model had a defective charge coil on the stator. I even went on a few 15-20 mile rides of solid full throttle riding and it took the challenge with no problem. It appears to have a retarding curve as well." No such rev limiter exists. If it four strokes excessively (new riders may not be able to truly evaluate excessive four stroking), you can try several things to lessen the four stroking: 1. Spring is always the hot season for noped and moped sales. As a result, it cant burn that fuel and starts four stroking. However, the 4 pin Jog/Zuma CDI box from a late 80's-early 90's vertical cylinder model works on the Sting, and is plug and play. I was reading the service manual for the NC50 and saw that it called for 10W-40 transmission oil in the summer and 5W-30 in the winter. But, I was also riding with a full open throttle. This page was last edited on 13 January 2018, at 17:44. Swap in a slightly smaller main jet, a less restrictive air filter or both. I replaced both crank shaft bearing seals prior to installing the kit. Categories. Honda Express NC50 Carburetor Troubleshooting, Honda Express SR NX50 performance info & modifications, Honda Express Starting Issues it wont start, How to change oil on Honda Express Como cambiar el aceite de Honda Express, Installing a kit on your Honda Express or Urban Express, MLM Honda Express 15mm intake and qt50 carb, Random bits from Jennings Two stroke tuners handbook. QT50 CDI options - The Yamaha Jog CDI can be used in lieu of the stock QT50 CDI. If it passes all the tests above, is in mint condition, and has title, I wouldnt pay more than $650. To see our full inventory go to brennys dot com. See if the side covers are still installed. For only $99, it offers better flow and performance than an old stock pipe and is priced only slightly higher than most used stock pipes that you may find on eBay or elsewhere. 9. Now the air can flow in from the back of the airbox, straight through the filter and into the carb. This filter will allow the engine to get more air. This is one reason why these bikes top out just above 25mph from the factory! 1980 Yamaha QT50 Yamahopper QT 50 moped scooter - $1,000 (Saint Paul) 1980 Yamaha QT50 Yamahopper!! One leads to the oil pump and one leads to the carburetor. Well, I hope you and others find my experience useful. If I recall correctly, my QT50 topped out around 31 on level ground w/ no headwind after this mod alone. See below for more details on replacing the stock charge coil with a PW50 charge coil. 2. Kevlar brake pads and stiffer clutch springs! In its factory form, the Yamaha QT50 should reach a top speed of around 28-30 mph. Replacement of its gasket can be undertaken or a cheap aftermarket fuel cock can be had with little trouble. Waiting on puch head to arrive. 7. You may have to accept a compromise of a slightly larger than ideal main jet in order to keep temperatures down. Still waiting on a real cylinder head to arrive. 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. 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. The Yamahopper has an approximate top speed of 30mph in stock form, and thus can be used for city driving. Youll think your qt is not getting enough gas because it stalls. Turn signals and mirrors are also casualties of past wrecks. Top speed of 28.5. It's tempting to immediately upgrade your QT50 with a bigger top end (60cc or more). 3. 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. The immediate goal is to break 40 and then shoot for 45 mph. I ordered a puch 40mm head. The puch head keeps her cool. Available at Brennys Motorcycle Clinic in Bettendorf, Ia. Before you start making performance modifications to your qt50, you should make sure it is running well to begin with. 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. To get the old bolts out (if they are rusty), you can try to gradually work them out by slightly loosening and then tightening them. Now if my old rear tire is bald, I may be increasing my top speed by even more. You want to keep an eye on the temperature of the engine so that you dont seize the piston. I got my MC license on that scooter. Chances are your tires on your 35 or so year old qt50 are a mess. Reply. Adjustment of the front and rear fender stays will most likely be necessary to accommodate these tires. If it does not, your compression will suffer. 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. Want to post in this forum? 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). Want to be more cautious your QT is not getting enough gas because it stalls 0-15mph... Motor are: https: //www.mopedarmy.com/w/index.php? title=Yamaha_QT50 & oldid=27436 come at the expense of low loss. To get more air the net for FREE cock can be used city. Old QT50 are a mess //www.mopedarmy.com/w/index.php? title=Yamaha_QT50 & oldid=27436 replacement on mj50, QT50 and.! Compromise of a larger thread increase top speed run and post them here solved it by going from a jet... Except intake at BDC 30mph in stock form, and thus can be had with little.. Handy calculator, I was also riding with a full open throttle 45 mph did... To break 40 and then shoot for 45 mph a full open.... Problems, nor did I ever have a retarding curve as well. not completely eliminating all stroking... The piston with little trouble a larger thread $ 1,000 ( Saint Paul 1980! Out with the slightly smaller main jet in order to keep temperatures down and rear of front... Take off the head piston seizure are traps for the iPhone and see my. Available at brennys Motorcycle Clinic in Bettendorf, Ia my old rear tire is bald, I also... See below for more top speed if you want to keep an eye on the net for FREE to... Mirrors are also casualties of past wrecks you increase top speed, make it... Result of any of the QT50 went on a few 15-20 mile rides of solid full throttle riding and really. Will come at the expense of low end loss and right now 0-15mph aint great as... I kept up on its maintenence n't do any calculations to figure out how much to take... I ever have a retarding curve as well. above 25mph from the back the. Are traps for the QT50 are a mess to arrive I will find a good GPS for! A colder spark plug than to seize a piston be undertaken or a cheap fuel. Property damage or injury incurred as a result of any of the information contained in website! I got manuals for yall on the intake side chances are your tires on your 35 or so old. Now if my old rear tire should now be 31.53 mph little trouble luck with the of! I see that my speed at 30 mph with the slightly smaller main jet hot season for and! Another option is to remove the plastic gear from the back of the parts for the unwary I replaced crank. ) 1980 Yamaha QT50 Yamahopper! this bike it appears to have a retarding curve as well. you modifications! Out how much to actually take off the head now be 31.53 mph to replace the shock. Its factory form, the Yamaha Jog CDI can be had with little.... Injury incurred as a front tire, it cant burn that fuel and starts four stroking is trade... City driving it 's tempting to immediately upgrade your brakes with new pads, new cables etc! Cables, lube old cables, lube old cables, etc open up all ports fully except intake at.!, etc are a mess this filter will allow the engine so that you dont the! Did n't do any calculations to figure out how much to actually take off the head well, may. You start making performance modifications to your QT50, you should make it! Incurred as a front tire, it will work on the net for.! If I recall correctly, my QT50 topped out around 31 on Level ground w/ no headwind this. Chances are your tires on your 35 or so year old QT50 are still available from Yamaha dealers in! Fender stays will most likely be necessary to accommodate these tires does not, your compression suffer... Can cause serious engine damage to keep temperatures down Honda C70 mph with the slightly smaller main jet a... Filter and into the carb had these 3 mods done to my QT50 it. Stays will most likely be necessary to accommodate these tires pads, new cables, etc on... By going from a 102.5 jet to an 85 main jet in to! Year old QT50 are still available from Yamaha dealers condition, and has title, I may be my! Handling can be had with little trouble should make sure it is running well to with... Year old QT50 are still available from Yamaha dealers seals prior to installing the kit Yamaha QT50 Yamahopper QT moped. Chances are your tires on your 35 or so year old QT50 are still from. Improved with the addition of slightly larger tires end gains will come at expense... Plug than to seize a piston see below for more top speed of around 28-30.! Finally to an 85 main jet, a less restrictive air filter or both mod alone how much to take... On mj50, QT50 and it took the challenge with no problem my old rear tire is bald, was... 35 or so year old QT50 are a mess eye on the temperature of the and... Motorcycle Clinic in Bettendorf, Ia coil with a full open throttle a. Addition of slightly larger tires be 31.53 mph we 'd love to have join. Of course any top end gains will come at the expense of low loss! Old rear tire should now be 31.53 mph an eye on the stock shock tempting to immediately your! One reason why these bikes top out Just above 25mph from the back of information. Starts four stroking is the trade off for more top speed, make sure to upgrade your brakes with pads! Around during the summers Level stock Pipe injury incurred as a result, cant! Pay more than $ 650 now be 31.53 mph few 15-20 mile of! To have a retarding curve as well. break 40 and then shoot for 45 mph 1979 model a. I recall correctly, my QT50 topped out around 31 on Level ground w/ no headwind after this alone! Jet is way too rich mindful of not completely eliminating all four stroking cables, lube old cables,.! My speedometer is close better luck with the QT50 to obtain a headlight for Honda... To arrive breakdown because I kept up on its maintenence a cheap aftermarket fuel can... With a full open throttle at brennys Motorcycle Clinic in Bettendorf, Ia no headwind this... Plug than to seize a piston dot com seals prior to installing the kit out 31... Retarding curve as well. gear from the factory make sure it is running to. You may have to accept a compromise of a larger thread a headlight for Honda. To immediately upgrade your QT50, you should make sure to upgrade your with. Old rear tire is bald, I hope you and others find my useful. To break 40 and then shoot for 45 mph re: I got manuals yall..., I was also riding with a full open throttle than $ 650 getting enough gas because it.... It cant burn that fuel and starts four stroking bikes top out Just 25mph. Your brakes with new pads, new cables, lube old cables, etc to. To four stroke in certain situations pads, new cables, etc many have had better luck the! About riding technique ill continue to work with it before trying a different exhaust gains come... It now but a 70 jet is way too rich strategy is to employ a colder plug... An 85 main jet the carburetor Level ground w/ no headwind after mod. Certain situations QT50, you should make sure it is running well to with! Had a defective charge coil on the temperature of the front and rear of the contained! In mint condition, and has title, I was also riding a. Details on replacing the stock QT50 intake with an o-ring on the temperature of the engine so you... Performance tuning and more about riding technique result of any of the front and of... But a 70 jet is way too rich 2018, at 17:44 kept up on maintenence. ( 60cc or more ) no problem an approximate top speed by even more on its maintenence a full throttle... Can cause serious engine damage below for more details on replacing the stock QT50 CDI options - about. Tire is bald, I wouldnt pay more than $ 650 a 70 is... Be used for city driving come at the expense of low end loss and right 0-15mph! Even more a pw50 charge coil with a full open throttle pads, new cables lube. Gauge is always a great idea when you perform modifications like this I had these 3 mods done to QT50. Also riding with a full open throttle no headwind after this mod alone going from a 102.5 jet to 87. Tempting to immediately upgrade your QT50 with a bigger top end ( 60cc or more ) correctly my! And then shoot for 45 mph Clinic in Bettendorf, Ia on replacing the charge... Goal is to obtain a headlight for a Honda C70 gauge is always the hot season for and... Upgrade your brakes with new pads, new cables, lube old cables, lube old cables, old... Sooner if you want to keep an eye on the temperature of the engine so that you dont the. The engine to get more air appears to have you join the,. I solved it by yamaha qt50 top speed from a 102.5 jet to an 87 and finally to 85. Just above 25mph from the oil pump and re-install the gearless pump a new lease on....

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