Other tire options (in stock at the time of editing) included Shinko SR244 Dual Sport tires (14"x2.75"); Shinko SR241 Dual Sport tires (14"x2.75"); vee rubber VRM 020 moped tire (14 x 2.25); irc inoue tire - (14" x 2.25") hod rodddder; Kenda K261(14" x 2.25"); Yokohoma World Tour 956 (14" x 2.25" and 2.00" - not sure if you can find this still); Guang Li Dirt Tire (2.50"-14"); Tyre HEIDENAU K66 (80/80-14" - may or may not work and may require loss of rear fender). 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.
Minor maintenance and it shows me its capabilities as well as my problems that need attention so I recommend this bike because it cheap and reliable! I need an exhaust as the one I have is broken. Again the ravage of time has taken its toll on this little device, and it's not uncommon for the OEM petcock to leak in one or more of its three positions. Also check the foot pegs to see if they are bent. The IRC NR-77 moped tire - 14 x 70/90 will mount up on the front and rear but fender stay adjustment will be necessary especially to provide clearance in the front.
It’s in my garage. Yamaha set these peds up to run rich with a stock main jet of 70 in the Mikuni carburetor. We just bought a Yamaha QT50L. The bikes all came with turn signals and oil injecti… After the main jet, dial in the jet needle. In terms of keeping temperatures down, you will want to replace your crank shaft bearing seals. Yamaha used two different stock exhausts on the qt50.
The seller will make you thicker base gaskets in copper or aluminum. 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. 174 - 63875 Mespelbrunn Telefon: 0151 - 40147593 The main jet should be your initial focus. Like I said, the stock exhaust is very restrictive and it probably has carbon build-up. The VM18 will require MLM's intake designed for the VM18. Engine failure is imminent. Would it be possible to send me pictures and size of the all warning lables by the speedo and the batterie cover . This was a no-pedal (noped) machine, with fixed footrests and a kickstarter. I believe that Yamaha used a lousy charge coil on all models.
A bigger cylinder head would also help with cooling.
One had an "S" shaped header and the other had a much straighter header. As with any engine modification like this, you will need to install a larger main jet in the carburetor. Just in case I need to buy parts I would like to know if the “L” is important. But it’s topping out at 25 on level ground. The simplified driveshaft setup makes wheel changes easy. Amal 15mm carburetors are rumored to work.
That is just not going to work well. Save my name, email, and website in this browser for the next time I comment. New bolts with some anti-seize compound are recommended. 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. Slightly messy, but probably few owners did it. Easier to mix 50:1 super gas instead of unleaded because its a cleaner ethanol free gas which is very beneficial in keeping the exhaust at a minimal smoke show only at start up. When you increase top speed, make sure to upgrade your brakes with new pads, new cables, lube old cables, etc. What are your thoughts? Manufacturer: Yamaha Production: 1981–1996 Predecessor: DT50M Successor: DT50R Class: Motocross / Enduro Engine: 49 cc (3.0 cu in) 2-stroke single Transmission: 5-speed or 6-speed, multi-plate wet clutch Wheelbase: 1,280 mm (50 in) Seat height: 820 mm (32 in) Fuel capacity: 8.5 Liters (2.2 US gal) Top Speed: ~60mph Suspension: This clutch unit had its own oil supply; the four-stroke kind that the manual said should be changed once a year. Another option is to pull out the oil injector, remove the plastic gear on the end and then re-install. Our Retrospective about the Yamahopper was originally published in the print edition of Rider in 2017. 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. 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. You can wire in a different CDI following the diagrams from here: Hobbit CDI Wiring
Proper jetting of the carburetor (main jet, jet needle, and idle jet) is critical to keeping temperatures in a manageable range. Its a cutie and its very reliable. Kenda also makes a number of 60/100 x 14" dirt tires that may work as well.
My daughter bought one at age 13 to ride around Frye Island in Maine in the mid 1980s.
I probably have more if I dig around. I still plan on replacing the crank shaft seal in hopes of gaining a little more from the stock setup.
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). 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. A single seat sufficed, as this was a one-person machine, having a maximum “loading limit” of 170 pounds, so large people were legally excluded. Honda Express with tecno boss exhaust and 1.5mm cylinder spacing.
If the turn signals fail to blink, the flasher relay has seen better days. Here’s my Orange 77 Express with SHA style carb which was good for a 2-3 mph increase over stock carb.
I bought one while assigned at Ft. Ord, (Monterey) California in 1980, My wife worked at Cannery Row and would sometimes ride the Moped to work, we were sent to Germany next, I sold it when we came back stateside at Ft.Sheridan, (Chicago) Illinois, In hindsight, I should have kept the Moped… Had a blast while I owned it !!! According to a speedometer on my phone, it was around 26-27. I’d be happy with 1 mph. Another culprit in QT50 excessive four stroking is the oil pump. I always wanted a blue one but the day we went to buy it they only had red. This jailbreaks the relatively generous exhaust port (in the stock configuration, the piston partially covers a portion of the exhaust port at bottom dead center; the rev plate raises the cylinder jug and thus allows the piston to fully expose the exhaust port at bottom dead center). A 100 to 105 main jet should get you in the ball park but every bike is different. 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. You can find NGK BP8HS (bigger number means colder plug) plugs (NGK also makes 5, 6, and 7 rated plugs). I’m still undecided on what weight synthetic oil to try. Hi, I have one since 1988 and have keep’t it since. Big smile on my face I took it to the end of my street and back and I had a blast. Some have installed the HPI CDI mini rotor ignition system for yamaha QT50. I might stick a performance exhaust on this next to see how it does. No such rev limiter exists. QT50 Tire options - A taller and wider tire will improve handling, ride, braking and, potentially, top speed. Cone mesh air filters of the 28-29mm variety are plentiful and cheap on ebay or amazon and equally effective. 6. 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. My Honda Express at the time of purchase.