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. In the end, I was able to get the QT50 consistently up into the 35-40 mph range even on slight uphills, and I was able to almost hit 50 going downhills and also by catching a lucky draft from an SUV on level ground (which was probably one of the dumbest things I've done in my life so far). That is just not going to work well. Of course, this makes me wonder if I can use an IRC NC 77 80/9014 tire. I used a 65 main jet and it seems to be pretty dialed in. Add a new exhaust gasket and put a little anti-seize on the new bolts before installing. Adjust the oil injection pump; Day 6 I let her eat today. 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. It also seems to help if you reconnect the common ground shared between the charge coil and the light coil. At top speed and when the engine is under little load, you may hear the engine note change tone from a high pitched whine to a lower and rougher growl. Plastic parts may be the most difficult of all as they did not age well if left in the elements. 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). Reducing four stroking through a smaller main jet, more free-flowing air filter or both might get you 1-2 mph more. 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. Stock cylinder head is horrible on cooling. 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. I go over some pretty simple cylinder modifications to get more speed.spacers - https://www.treatland.tv/SearchResults.asp?Search=honda+metal+spacer+basespac. Re: 1982 Yamaha QT50 Yamahopper top speed. Almost all states require title to obtain license plates and registration. Another culprit in QT50 excessive four stroking is the oil pump. Once it gets on the pipe though, hang on! . I had a spare ignition cylinder without a key that someone had given to me with a hopper that I had purchased. Other cooling methods include running a thicker head gasket (or more than one head gasket) to reduce compression (you can also reduce compression by increasing cylinder head chamber size) and running a Jog cdi with a curve that allegedly retards timing at higher rpms. One leads to the oil pump and one leads to the carburetor. Engine failure is imminent. You may need to bump up to a 72.5 main jet with this filter. Chances are your tires on your 35 or so year old qt50 are a mess. The temperature gauge will be your other. 41.6mph. Im going to look at changing the jetting next. I ordered a puch 40mm head. I just bought an MLM peoples sidebleed pipe for my QT50/MJ50. Performance upgrades, as listed above, exist for the QT50 that will make 50 mph~ attainable. The oil pump, slide spring and junction box all provide tension to snap the throttle back after you let go. Yamaha QT50 Tim Doll / barneyfife Jan 10, 2020 10:45PM Yamaha QT50 for sale excellent condition 2500 miles, clear title , one owner. 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. 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. Low end was miserable at 110 psi. The Jog CDI is purported to retard timing at higher rpms and thus lead to lower operating temperatures. What should you pay for (or sell) a Honda Express? a video on this modification here at the bottom of this page. Jan 09, 2023 08:37PM. This posting echoes Fred's post to some extent, but I was lucky that my dad had porting experience. Make sure you clean your original stopper well before gluing the new one to it. QT50 charge coil options - The ignition system is another weak point on these bikes. Puch head arrives Monday. 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); A stock QT50 has a top speed of 30 mph, and takes a while to reach it. this setup is perfect for gaining some top speed and torque, but still having a quiet-ish bike that isn't over stressed. Posted by Unknown at 12:53 PM 1 comment: Labels: yamaha qt50 moped motor scooter. Half the package or less is plenty. When I grabbed a handful of throttle when on the pipe (anywhere above ~18mph for mine), that tiny chainsaw motor meant business! 2 stroke engines are designed to four stroke in certain situations. Expect a top speed gain of at least 10% over stock with this modification. Web designers, SEO consultants, etc. Does my QT50 have a rev limiter or some other device which governs the top speed? Unfortunately, its fairly common for people to lose the key. Chances are you still wont get a good idea of how rusty the tank is even by doing this. Ill continue to work with it before trying a different exhaust. 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. 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. Stay tuned. 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. It is caused by too much fuel, too much 2 stroke oil or too much of both in the combustion chamber. Day 1 49cc engine is on my blue qt50. Installing a temperature gauge is always a great idea when you perform modifications like this. Another option is to remove the plastic gear from the oil pump and re-install the gearless pump. Ive got several other ideas but will reveal them one by one as I make progress from test to test. I thought the stock exhaust might help in this regard. The VM18 will require MLM's intake designed for the VM18. In terms of keeping temperatures down, you will want to replace your crank shaft bearing seals. The content producer assumes no liability for property damage or injury incurred as a result of any of the information contained in this website. These are awesome mopeds, they don't weigh a lot so they are nimble, being a moped it's legal to park anywhere a bike can (including bike racks), goes about 30 mph with a twist. A bigger cylinder head would also help with cooling. Yamaha has tuned the engine to do this in that situation and it represents a compromise. Damn that was sweet! Signaler un abus. My initial acceleration may be a bit slower with the bigger rear tire. This is the trade off for more top speed. Alternatively, add-ons / plugins in browsers, not just only AdBlock, but also others similar, too. Because I opened up the reed block slightly, a 2.5 increase in jet size is significant. 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. Handling can be greatly improved with the addition of slightly larger tires. So, in essence, it would be getting too little fuel. 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. Picture the maze that the incoming air had to follow just to get to the carb. 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. Maybe Ill shoot for Pete Roses number. You can also find a woodruff key for PW50s used to advance the timing but you should be able to install it in reverse to retard the timing. If you are eventually planning on a bigger top end, go with the VM18. 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. Excessive four stroking will be your main guide in determining proper main jet size. 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. Buy yamaha qt50 online with fast delivery and free shipping. Right and left side crankshaft seals can be found on ebay or treatland.tv. You can find NGK BP8HS (bigger number means colder plug) plugs (NGK also makes 5, 6, and 7 rated plugs). Traduire le commentaire en franais. Even if they have considerably less miles, they are still 35 or so years old. You need to get another Yamaha Center Stand Stopper (part no. Rusty tanks can also be cleaned up and made to work. This headlight has a replaceable bulb and fits perfectly in the QT50's headlight ring. Its like an old house. Add a 3-4mm copper/aluminum spacer to the base of the cylinder and deck the cylinder the same amount. Ill put the circuit pipe on next and we should jump to over 40. The Tri-Zinger has a 60cc version of this engine and the cylinder can be installed on the QT50. I'll make videos of each top speed run and post them here. But, I was also riding with a full open throttle. Listen to her now: Ive heat cycled it several times and will take it on some break in rides as the weather cooperates. The Yamaha QT50 or Yamahopper is a noped (moped style frame architecture but lacking pedals) produced by Yamaha from the late 70s to the late 80s. Ive used the vinegar and salt method but now mainly use EvapoRust. Reply Stephen Keller / keller_stephen Jan 10, 2020 11:49PM Price? Better a fouled spark plug than a seized piston, right? Day 3 I put a bigger pilot jet in the blue Qt. Call 563-359-7222. Trail Tech offers a 14mm gauge for $39 or so. 10. Be mindful of not completely eliminating all four stroking. 3. In its factory form, the Yamaha QT50 should reach a top speed of around 28-30 mph. It can be incredibly frustrating to spend $200 on a performance exhaust and then have the kickstand bang it every time you use it. 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. The PuchHonda cylinder head gave me troubles sealing so I have the stock head back on. 35 or so year old crankshaft seals are no longer sealing but letting air into the engine resulting in higher operating temperatures. It is a 2 stroke,. The MLM exhaust will also require you to install a bigger main jet. Try a slightly smaller main jet; The engine being slightly under 50cc, it was legal in some states to operate this diminutive motorcycle without a drivers licence thereby making the QT50 appealing to teanagers. Check and see if all the lights and horn work. The header on my stock exhaust is kind of beat up so Im running a double exhaust gasket to seal it up. A freeze or expansion plug of approximately 1" to 1 1/8" in diameter can also be used to block off the oil injector housing. 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