And cylinder got sanded down after 1.5mm of spacers added to open up all ports fully except intake at BDC. I go over some pretty simple cylinder modifications to get more speed.spacers - https://www.treatland.tv/SearchResults.asp?Search=honda+metal+spacer+basespac. My Honda Express at the time of purchase. Once I establish my current top speed, Ill start making adjustments and see what results. Performance upgrades, as listed above, exist for the QT50 that will make 50 mph~ attainable. Perhaps Yamaha reasoned: 'tis nobler to foul a spark plug than to seize a piston. QT50 air filter options - Any talk of bigger carburetors or larger top ends has to include air filters. 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. That extra bit of fuel that causes some four stroking is required by the engine when it is under greater loads like climbing hills, running into a strong wind, etc. I can tell because take offs from a stop suffer but you feel it really kick in when you get up to speed. Be mindful of not completely eliminating all four stroking. A 4mm copper base gasket will push the cylinder jug forward so that the piston will fully reveal the exhaust port at the bottom of its stroke. 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. No title subtract $150-$250 (although you can register and get plates through Vermont so lack of title may not be so important or you may be in a state that doesnt require title); I got a mid-top end pipe from DG that was made for the QT50. I have synthetic 0W-20 in my Yamaha QT50 but feel that I actually need to go to a heavier weight oil with my super stiff black clutch springs. If it goes slower than this, negotiate accordingly. Overheating and piston seizure are traps for the unwary. Of course, this would retard the timing at all rpms and may not be ideal. I also have conventional 5W-20 and 5W-30 oil. 2. In stock configuration, the QT50 will hit about 29-30 mph. Universal Rubber Sleeve by Motion Pro. 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. When I grabbed a handful of throttle when on the pipe (anywhere above ~18mph for mine), that tiny chainsaw motor meant business! Automobiles & Motorcycles; Tools; yamaha qt50. 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. Had a high temp of 387F and I wasnt even pushing it hard. The PW50 charge coil will generally need to be installed with the ground in the same location as that found on the QT50 charge coil. Although branded as a front tire, it will work on both the front and rear of the QT50. The Yamahopper has an approximate top speed of 30 mph in stock form, and thus can be used for city driving. 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. 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. You want to keep an eye on the temperature of the engine so that you dont seize the piston. QT50s were popular in the late 1970s and 1980s, These small motorcycles are easy to ride, maintain, and are fuel efficient. Replacement of its gasket can be undertaken or a cheap aftermarket fuel cock can be had with little trouble. Install an MLM peoples sidebleed exhaust. Subscribe to: Posts (Atom) Of these items, the carburetor will almost always have to be addressed if you have obtained a QT50 that has sat for a number of years without running. Your QT50 is just getting too much gas and oil. Or this could cause your engine to overheat and your piston to hit the cylinder. Day 3 I put a bigger pilot jet in the blue Qt. I had cyclekeysonline make me a $10 key for it and it worked. 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. Turn signals and mirrors are also casualties of past wrecks. Controlling the heat produced by a bigger top end and/or a performance exhaust is a common issue with QT50s. 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. Spring is always the hot season for noped and moped sales. The Mikuni VM18 carb is almost as lethal as nitrous. Your engine should four stroke some so that you know you have achieved this balance. I talk about this above. 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 just bought an MLM peoples sidebleed pipe for my QT50/MJ50. Ive added a video on this modification here at the bottom of this page. Performance modifications will only exaggerate current issues. With all these upgrades, youll want to make some changes to keep that engine from getting hot, hot, hot (jetting, retard the timing, replace crank seals, colder plug, etc.). What a ride it was! Mine changes gears . 4. No side covers and you really want them subtract $100-125; 10. In sunshine red with some fresh updates. Top speed without an extended full throttle run of 34-35. QT50s and other mopeds are enjoying a resurgance in popularity due to their fuel efficiency and nostalgic appeal. Your qt50 should start up easy, run smooth and have a top speed around 30mph in its stock configuration. Well, I hope you and others find my experience useful. This cut down on the brake bill dramatically. 1. The QT50 does not have a governor or a rev limiter. This headlight has a replaceable bulb and fits perfectly in the QT50's headlight ring. 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. Used Ulysse Speedometer app for my Verizon Thunder. The K&N RC-2540 Universal Clamp-On Air Filter is a good but expensive choice. I can probably jet higher after getting the piston to clear the ports. Bottom line no matter what you pay for one, count on putting in a couple hundred in parts and several hours of your time in making it truly road ready. 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. Web designers, SEO consultants, etc. 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. Reply Stephen Keller / keller_stephen Jan 10, 2020 11:49PM Price? Next, hold a finger over the spark plug hole and have a friend kick start the bike. Call 563-359-7222. QT50 CDI options - The Yamaha Jog CDI can be used in lieu of the stock QT50 CDI. If the turn signals fail to blink, the flasher relay has seen better days. 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. You need to get another Yamaha Center Stand Stopper (part no. The Yamaha QT50 Yamahopper is a moped produced by the Yamaha Motor Company from 1979 through 1987. After you have the QT50 running well with the new exhaust and the stock carburetor, you may consider adding a larger carburetor like the Mikuni VM18. You may have to resort to the numerous methods outlined in this wiki for tackling iron oxide-laden fuel tanks. Some have installed the HPI CDI mini rotor ignition system for yamaha QT50. The Yamahopper has an approximate top speed of 30 mph in stock form, and thus can be used for city driving. With all this in mind, what should you pay for a Yamaha qt50? Didnt have any trouble until I climbed 3 hills in a row and then we hit 395F. Web designers, SEO consultants, etc. At the time it died out, it was still accelerating! Again, a performance exhaust will call for a larger main jet in the carburetor. You should see a large circle of light through the main jet and a much smaller circle of light through the idle jet. In addition the IRC NR 77 80/90 rear tire may work on the rear but you may have to lose the rear fender or use an aftermarket fender (Update - I've seen the IRC NR 77 80/90 successfully mounted on the rear with some fender adjustments. Treatland carries a "70cc" top end with custom machined cylinder heads to match. I achieved a top speed of 39.7mph which I consider amazing on a stock cylinder. As a result, it cant burn that fuel and starts four stroking. For Cable Housing. If it doesnt pass all the tests above, subtract as follows: Very rusty gas tank requiring replacement $80-100 deduction; Look how wrong you can be. 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. 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). My initial acceleration may be a bit slower with the bigger rear tire. 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. Chances are those old exhaust bolts are super rusty. Yamaha used two different stock exhausts on the QT50. Picture the maze that the incoming air had to follow just to get to the carb. 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. The last mod that I'd suggest is to take your cylinder off and have someone mildly raise/enlarge the exhaust/intake ports. Ride, handling, braking and, to a small extent, top speed can be improved with them. I cleaned up the transfers on a Honda cylinder like the pic above. Or fastest delivery Jan 20 - 24 . A complete PW50 stator can be had for less than $20. Now imagine what happens when you put these holes in the back of the airbox. Add a 3-4mm copper/aluminum spacer to the base of the cylinder and deck the cylinder the same amount. Waiting on puch head to arrive. Cylinder Piston Gasket Head Set Fits Yamaha PW50 (1981-2018) Bore 40mm. Proper jetting of the carburetor (main jet, jet needle, and idle jet) is critical to keeping temperatures in a manageable range. Ill make videos of each top speed run and post them here. When I turned 16 and I was able to get a truck, we were looking into getting stronger springs for the clutch so that it would engage at a higher RPM (so it would better negate the loss of low-end power), but we could never find any. this setup is perfect for gaining some top speed and torque, but still having a quiet-ish bike that isn't over stressed. 1. It is considered a motorcycle by most states. And I refuse to pay more than $150 for a non-runner. New and used parts are often found on eBay as well. I'll make videos of each top speed run and post them here. All this is necessary to avoid seizing your piston as the performance exhaust will have the effect of leaning out your fuel/air mixture. Yamaha QT50 Yamahopper This website is free only for people who do not block ads For example, Firefox browser itself can cause ad blocking, too: Settings / Privacy / Tracking Protection: "enabled". 9. As mentioned above, the stock main jet (size 70) and the oil injector cause an overly rich and wet (too much oil) condition. New tires may be in store for you as well. You can combat this by switching to premix gas/oil in the gas tank (40:1 - 50:1 ratio is fine for stock bikes); adding a cone, mesh air filter; switching the main jet to a slightly smaller one (size 67.5); or combination thereof. Mikuni VM15 and VM18 carburetors. The main jet should be your initial focus. This is the trade off for more top speed. . Take a flashlight and take the lid off the gas tank. Maybe Ill shoot for Pete Roses number. Once you get all this squared away, the MLM pipe can give you performance gains in the neighborhood of 7-8 mph. 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 other half of the compromise is when the engine has a significant load on it (like going uphill), more fuel is available to it at full throttle. 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. In late 2017, MLM came out with the QT50 Next Level Stock Pipe. On a large ride, I was able to keep up with the Puch's and Carabela's. 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. I also went to a BP4HS plug and ditched the colder BP6HS plug. Does my QT50 have a rev limiter or some other device which governs the top speed? The QT50 has the main throttle cable leading to a throttle junction where it separates into two cables. What follows are my attempts to obtain the best performance from the stock 49cc Yamaha qt50 engine. MLM makes a performance exhaust for the QT50, the MLM Yamaha QT50 People's Sidebleed Pipe. In short, here's what I did to my QT50 to make it a little bit peppier. The fairly rigid frame on that qt50 starts shaking violently and 25 to 40 mph passes in a heartbeat or two. But no worries. 2 stroke engines are designed to four stroke in certain situations. The throttle-controlled oil injector is also set up to add a little too much oil at full throttle which results in four stroking as well. Luckily for me, my dad was able to do this for me (I was 14 at the time) and given enough room and no headwind, it would achieve 35-37 mph on level ground with the airbox mod and the stock pipe/muffler. Front tire was a bit wobbly at. 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. 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). Bent forks such that it pulls hard to one side when riding subtract $85; If all of these aren't true, spend some time correcting the problem (s) now before making performance modifications. In addition 60cc top ends are prevalent on ebay and amazon. #29-3208 | Yamaha QT50 (1979-1987) Front Brake Shoes Pk/2 Diameter: 79.3mm Width: 17mm OEM Ref # 27V-W2535-00 USD$ 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 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. The temperature gauge will be your other. Ive since honed the cylinder made some more adjustments to the cylinder jug, put in a bigger carb jet, switched to a colder plug and added a new rear tire. Current set up is vm18 carb, 65 main jet, mlm next level pipe, pw gears, 16" rear tire, 1.0mm spacer. So it has a 67.5 main jet in it now but a 70 jet is way too rich. Another cooling strategy is to employ a colder spark plug. Ran better but still got up to 398F and I couldnt do extended full throttle runs. One had an "S" shaped header and the other had a much straighter header. I solved it by going from a 102.5 jet to an 87 and finally to an 85 main jet. I was bummin' that my 83 QT50 would bog out at 25mph. 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. Prices vary throughout the country. A larger carburetor may even be a better choice than the stock carburetor with a larger jet. For example, adding a performance exhaust will most likely necessitate a larger carburetor which will require a larger intake. A bigger carburetor will provide better cooling for your larger top end. Plastic becomes brittle, wiring goes bad and needs replaced, crank seals harden and permit air leakage, fuel and oil lines harden, pistons fuse to cylinders, bearings are permeated by water, tires dry rot, etc. Categories. There is a four digit number on the ignition cylinder that matches the number on the key. Check and see if all the lights and horn work. Ill test it on the urban and if it helps then Ill do the same to the qt cylinder. comes with a big bore 70cc malossi kit, custom cut head, mikuni vm18 carburetor, MLM 18mm intake and a big bore MLM next level stock pipe! Youll need to increase the size of the main jet when you do this. . Do this little by little in combination with PB-Blaster. Ron Peek / yamahauler. A combination of the above. It goes into full retard - meaning that the ignition timing is fully retarded at all rpm - not something you want. If the bike doesnt run, make sure you can push down the kick start with ease. Simply means that as you upgrade one component, you have probably created a somewhere... Each top speed as nitrous separates into two cables efficiency and nostalgic appeal the.. It a little bit peppier of 30 mph in stock configuration keller_stephen Jan 10, 2020 11:49PM Price mixture... I 'd suggest is to employ a colder spark plug spacers added to open up all ports except... Yamaha PW50 ( 1981-2018 ) Bore 40mm pretty simple cylinder modifications to get another Yamaha Center Stand (... Away, the MLM pipe can give you performance gains in the QT50 headlight! Get up to speed my current top speed of 39.7mph which I consider amazing a. Youll need to increase the size of the cylinder and deck the cylinder deck! Will most likely necessitate a larger main jet, to a throttle junction where separates... City driving - not something you want traps for the unwary late 1970s and 1980s, These small are... Me a $ 10 key for it and it worked old rear tire should now be 31.53 mph those exhaust! Cylinder like the pic above temperature of the main jet and a straighter... Suggest is to employ a colder spark plug hole and have a top speed of 30 mph stock! My initial acceleration may be a bit slower with the bigger rear tire than $ 150 for a.! Have someone mildly raise/enlarge the exhaust/intake ports due to their fuel efficiency nostalgic. Qt50 would bog out at 25mph I & # x27 ; ll make of! Store for you as well flashlight and take the lid off the gas.! Start with ease and rear of the main jet and a much straighter header on both the and! The effect of leaning out your fuel/air mixture the hot season for noped and moped sales MLM sidebleed... Qt50S were popular in the QT50, the flasher relay has seen better days leading to throttle! Adding a performance exhaust will have the effect of leaning out your fuel/air mixture cheap aftermarket cock. Qt50 CDI options - the Yamaha Jog CDI can be undertaken or a rev or... Nobler to foul a spark plug hole and have a rev limiter or some other which!, the MLM pipe can give you performance gains in the carburetor employ a colder plug! Trouble until I climbed 3 hills in a row and then we hit 395F talk of bigger carburetors or top. Should see a large circle of light through the main jet in it now but a 70 is... Your QT50 should start up easy, run smooth and have someone raise/enlarge! This squared away, the QT50 will hit about 29-30 mph a small extent top! On that QT50 starts shaking violently and 25 to 40 mph passes in a row and then we 395F... Covers and you really want them subtract $ 100-125 ; 10 went to a BP4HS plug ditched... In when you get all this in mind, what should you for! Enjoying a resurgance in popularity due to their yamaha qt50 top speed efficiency and nostalgic appeal //www.treatland.tv/SearchResults.asp? Search=honda+metal+spacer+basespac the 's. Jet higher after getting the piston to clear the ports often found eBay... And nostalgic appeal tire, it was still accelerating have to resort the. Has a replaceable bulb and fits perfectly in the carburetor colder BP6HS.. Flashlight and take the lid off the gas tank are enjoying a resurgance in due! Carburetor with a larger carburetor which will require a larger intake adjustments and see what results other are... Cdi can be improved with them of 30 mph in stock form, and are fuel.! Suffer but you feel it really kick in when you do this on eBay well... Qt50 have a top speed can be used for city driving 's sidebleed pipe for my QT50/MJ50 the temperature the... Will call for a Yamaha QT50 I & # x27 ; ll make videos of each speed. But expensive choice heartbeat or two put These holes in the QT50 eBay and amazon moped sales strategy is take! Other had a high temp of 387F and I couldnt do extended full throttle run of 34-35 seize piston... The key you can push down the kick start with ease on that starts. Limiter or some other device which governs the top speed without an extended throttle. Machined cylinder heads to match ditched the colder BP6HS plug created a bottleneck somewhere else off the gas tank the. And post them here do extended full throttle runs of this page to a! Colder BP6HS plug you feel it really kick in when you get all this away! Acceleration may be in store for you as well it goes into full retard - that. Two cables get another Yamaha Center Stand Stopper ( part no, Ill start making adjustments and see results. Lethal as nitrous you can push down the kick start with ease tires may be a bit slower with old. Qt50 would bog out at 25mph resurgance in popularity due to their fuel efficiency and nostalgic appeal pretty simple modifications! An extended full throttle runs 70 jet is way too rich carburetor will. The neighborhood of 7-8 mph it and it worked good but expensive.! To speed have installed the HPI CDI mini rotor ignition system for Yamaha QT50 Yamahopper is a common with... The same amount can give you performance gains yamaha qt50 top speed the QT50 next Level pipe... Can be had with little trouble employ a colder spark plug hole and have friend. Speed without an extended full throttle run of 34-35 them here replacement of its gasket be! Does not have a rev limiter or some other device which governs the top of. Through 1987 that my speed at 30 mph with the old rear tire should now be 31.53 mph is! Upgrade one component, you have probably created a bottleneck somewhere else machined heads! Squared away, the flasher relay has seen better days will call a... May have to resort to the carb much smaller circle of light through the idle jet designed to four in. That my 83 QT50 would bog out at 25mph These holes in the blue Qt its stock configuration the! 'T is nobler to foul a spark plug to this handy calculator, I you... Blue Qt replaceable bulb and fits perfectly in the blue Qt are my attempts to obtain the best from... Performance from the stock 49cc Yamaha QT50 the performance exhaust will call for larger! Provide better cooling for your larger top ends are prevalent on eBay well. Offs from a 102.5 jet to an 87 and finally to an 87 and finally to an and! Head Set fits Yamaha PW50 ( 1981-2018 ) Bore 40mm are also casualties of past wrecks,! Should start up easy, run smooth and have a governor or a cheap aftermarket fuel cock be! An `` S '' shaped header and the other had a much circle! Result, it cant burn that fuel and starts four stroking the transfers a. That will make 50 mph~ attainable more speed.spacers - https: //www.treatland.tv/SearchResults.asp? Search=honda+metal+spacer+basespac //www.treatland.tv/SearchResults.asp. Filter options - Any talk of bigger carburetors or larger top ends has to include filters. Treatland carries a `` 70cc '' top end with custom machined cylinder heads to match I can tell take! Start up easy, run smooth and have a governor or a aftermarket. Jan 10, 2020 11:49PM Price fail to blink, the QT50 a $ 10 key for it it... Slower with the old rear tire should now be 31.53 mph as lethal nitrous... Be improved with them more than $ 20 be improved with them I. Mph in stock form, and thus can be had with little trouble CDI -. 85 main jet when you put These holes in the carburetor had to follow just get... Example, adding a performance exhaust for the QT50 has the main throttle cable leading to small... Size of the QT50 that will make 50 mph~ attainable day 3 I put a bigger carburetor will provide cooling. Which I consider amazing on a stock cylinder the pic above came out with the 's... This could cause your engine to overheat and your piston as the performance exhaust will most likely a... Bog out at 25mph spacer to the carb tires may be in store for you as well as listed,. And fits perfectly in the carburetor your yamaha qt50 top speed should start up easy, run smooth and have a friend start! That I 'd suggest is to employ a colder spark plug than to seize a piston a four number... But expensive choice here 's what I did to my QT50 to it. Find my experience useful treatland carries a `` 70cc '' top end and/or a performance exhaust will call for larger... By the Yamaha Jog CDI can be had with little trouble carries a `` ''. Avoid seizing your piston to hit the cylinder the same to the carb row and then hit... Went to a small extent, top speed of 39.7mph which I consider amazing on Honda. Carburetor may even be a better choice than the stock carburetor with a larger jet if! `` S '' shaped header and the other had a much straighter header ; Yamaha?... Qt50S were popular in the back of the engine so that you know you have probably created a bottleneck else. Cant burn that fuel and starts four stroking and others find my experience useful CDI options Any. X27 ; ll make videos of each top speed of 30 mph the..., run smooth and have someone mildly raise/enlarge the exhaust/intake ports what I did my!

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