Loving this build Yooth! Can't wait to see it done!
Luke.
Luke.
Yamaha QT 50 "Noped" project
- Thread starter yoothgeye
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yoothgeye said:A friend dropped off an old moped tank today, I have to clean the rust out of it, but it's absolutely PERFECT!!!
Here's the way I suspect it was supposed to be mounted to the original moped:
Here's how I plan to mount it:
I love it! I will be welding in a top tube to better secure the tank, but the nose of the tank fits the head tube perfectly at either angle.
Here is my AMF "Frankenbike" Roadmaster in its build stage...
Re: Yamaha QT 50 "Noped" project
It is 50cc with built in pedals and the AMF frame was a moped frame that had a friction drive originally. The back is a OCC triangle section with a beefed up rear rim running 12g spokes. The front wheel is a Worksman with a drum brake. I am also using a moped forks and will spring the seat.
It is 50cc with built in pedals and the AMF frame was a moped frame that had a friction drive originally. The back is a OCC triangle section with a beefed up rear rim running 12g spokes. The front wheel is a Worksman with a drum brake. I am also using a moped forks and will spring the seat.
yoothgeye
I build stuff.
This is the ugly part I've been not wanting to show anyone. The side cover was left off for who-knows-how-long as the bike sat outdoors. It's pretty rusty in there.
I'm wondering if the rusty threads on the crank will be a problem? I'm currently trying to sell my '78 Schwinn Klunker 5 to get some money for this moped, if that happens I may pick up a motor or crank off of eBay.
I'm wondering if the rusty threads on the crank will be a problem? I'm currently trying to sell my '78 Schwinn Klunker 5 to get some money for this moped, if that happens I may pick up a motor or crank off of eBay.
Spray some PB Blaster on there every day and you might be surprised, it might come apart.
yoothgeye
I build stuff.
dracothered said:
That's exactly what I've been doing.
There is a factory service manual online, I printed the 40-some pages of the original owners manual, but the service manual is much longer, so I just need to look at it online and see the process to remove the magneto, I haven't even tried yet, I've been more worried about the stuck piston, but it could be a combination of both.
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yoothgeye said:
The piston should be the easy part. I have done ones FAR worse and got them to run again. Most Yamaha scooters and mopeds will run on a ring and a prayer. Your biggest challenge is going to be getting spark from that rusty magneto. Long as you can get spark you're home free.
I had a Yamaha Chappy (Kinda like the old Honda trail 90)that was so bad when I got it the guy BET ME $50 (Purchase price) I couldn't get it running. I found out after I fixed it and went back for my money it had sat in a creak near the guy's house for 8 years that he knew of. It had a few gallons of swamp water in the engine oil, locked up tight, and ugly as sin. I took the head off, pounded on the piston with a hammer and block of wood, got it to go down and move, hand sanded the jug, didn't even replace the rings or piston just cleaned it up and stuck it back in. Redneckin' it all the way with NO money into it. About 5 hours and a little gas and away it rode.
Hold off on buying engine parts ~ I've yet to see anything not salvageable.
Of-course a screaming deal on a runner would be ok.
Expansion chambers and exhaust port height are tuned (Much like a cam) to make power at a certain RPM. A missmatched combo could make less power. Get it running STOCK first ~ it is engineeered to work that way ~ then open it up and let it breath and add fuel as it calls for it. Once you reach the limit of carb tuning there (Main / Needle / Pilot) then may look for exhaust options to play with. Expansion chamber should be a year or 2 down the road unless you know of a proven combo for stock porting.
You can attempt to pull the jug. It is likely that the jug may slip off with minor persuasion. Good chance the crank bearings are what is seized. What ever you do ~ be gentle. Heat & Vibration work wonders. A heat gun is best but a hair drier rates a close 2nd.
If it were me / I'd pull the motor from the chassis and build a jig (work stand) for it. Could even be a simple jig made from a combo of scrap 2x4's or 2x6's with threaded rod. YOu will need a flywheel puller or similar tool ~ I've pulled them with out one but I'm discouraged after mushrooming the last Recon crank when we pulled your parts motor. 3-piece Park crank tool may be a close fit if not too thick an ID. I have my Honda 50 Flywheel tool here too.
BTW ~ down the road you will want a second (spare) top end to play with porting options ~ when you get to expansion chambers. Eventually you will find your self HEREhttp://en.wikipedia.org/wiki/Two-stroke_power_valve_system
or HERE
Of-course a screaming deal on a runner would be ok.
Expansion chambers and exhaust port height are tuned (Much like a cam) to make power at a certain RPM. A missmatched combo could make less power. Get it running STOCK first ~ it is engineeered to work that way ~ then open it up and let it breath and add fuel as it calls for it. Once you reach the limit of carb tuning there (Main / Needle / Pilot) then may look for exhaust options to play with. Expansion chamber should be a year or 2 down the road unless you know of a proven combo for stock porting.
You can attempt to pull the jug. It is likely that the jug may slip off with minor persuasion. Good chance the crank bearings are what is seized. What ever you do ~ be gentle. Heat & Vibration work wonders. A heat gun is best but a hair drier rates a close 2nd.
If it were me / I'd pull the motor from the chassis and build a jig (work stand) for it. Could even be a simple jig made from a combo of scrap 2x4's or 2x6's with threaded rod. YOu will need a flywheel puller or similar tool ~ I've pulled them with out one but I'm discouraged after mushrooming the last Recon crank when we pulled your parts motor. 3-piece Park crank tool may be a close fit if not too thick an ID. I have my Honda 50 Flywheel tool here too.
BTW ~ down the road you will want a second (spare) top end to play with porting options ~ when you get to expansion chambers. Eventually you will find your self HEREhttp://en.wikipedia.org/wiki/Two-stroke_power_valve_system
or HERE
yoothgeye
I build stuff.
I hear that just opening up the breathing accomplishes a lot for performance, some drill a few holes in the airbox, I already have an open element air filter that I want to try. This may have to go with new jets. :?
Most say that this engine is not governor limited, but limited by factory tune, so some good speeds have been reached with just simple tuning. I want it to be quick more than fast, if it's fast and I get caught I could get in trouble, too fast and it's not a moped anymore, it's a motorcycle, and that would mean tags, insurance, and a motorcycle endorsement, but without a title, I think being impounded would be the next step.
Definitely running stock is the first step, then baby steps. I wanna keep it on the road and reliable.
Most say that this engine is not governor limited, but limited by factory tune, so some good speeds have been reached with just simple tuning. I want it to be quick more than fast, if it's fast and I get caught I could get in trouble, too fast and it's not a moped anymore, it's a motorcycle, and that would mean tags, insurance, and a motorcycle endorsement, but without a title, I think being impounded would be the next step.
Definitely running stock is the first step, then baby steps. I wanna keep it on the road and reliable.
yoothgeye
I build stuff.
Question...
The forks on this bike, would the shocks be "charged" or pressurized? Can I weld to the top of the crown without worry of the heat exploding the shock?
(this is the exact fork I have, just someone else's photo from eBay)
The forks on this bike, would the shocks be "charged" or pressurized? Can I weld to the top of the crown without worry of the heat exploding the shock?
(this is the exact fork I have, just someone else's photo from eBay)
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Oh just a tip if your motor is shot DON'T buy a Yamaha QT50 case, get a Yamaha MJ-50 Towny case it's 2 speed and bolts right up.
Also if you want to give it some speed you can add in parts from different Yamaha bikes, examples are:
Yamaha YT60 cylinder, piston, and rings (Basically a big bore kit), Yamaha MJ50 Towny two-speed crankcase and right-side swing arm (GEARS! also the right side swing arm helps stabilize the rear wheel at high speed), Yamaha PW50 rear gears (better gearing)
The YF60's(quad), YT60's(atv), MJ50's(noped) and PW50's(mini dirtbike) engines were all derived from the QT50's engine and all parts are interchangeable though some parts are slightly different, for example all model's right side crankcase half have right side trailing arm mounts, except for the QT50.
I know of a guy on Moped army that has a QT-50 that will do 70MPH and looks bone stock. :shock: :mrgreen:
Also if you want to give it some speed you can add in parts from different Yamaha bikes, examples are:
Yamaha YT60 cylinder, piston, and rings (Basically a big bore kit), Yamaha MJ50 Towny two-speed crankcase and right-side swing arm (GEARS! also the right side swing arm helps stabilize the rear wheel at high speed), Yamaha PW50 rear gears (better gearing)
The YF60's(quad), YT60's(atv), MJ50's(noped) and PW50's(mini dirtbike) engines were all derived from the QT50's engine and all parts are interchangeable though some parts are slightly different, for example all model's right side crankcase half have right side trailing arm mounts, except for the QT50.
I know of a guy on Moped army that has a QT-50 that will do 70MPH and looks bone stock. :shock: :mrgreen:
Should be just springs and plastic guides ~ like the Honda 50. I don't think they used any damping ~ certainly not pressurized. About any modern MTB fork would be a huge upgrade.
PW 50 ~ Hmmm Those parts are fairly easy to find. PW 50 CDi ignition upgrade?
Some of the China bikes / scooters are running dampened modern forks and disk brakes.
PW 50 ~ Hmmm Those parts are fairly easy to find. PW 50 CDi ignition upgrade?
Some of the China bikes / scooters are running dampened modern forks and disk brakes.
just setting the squish on the piston, jetting and fabbing a bigger expansion chamber can double or triple the horsepower of a two stroke. That's what we did when we raced the cheap Cag pocketbikes off Ebay. We could keep up with the Italians (the lower end ones).
I can't wait to see your project finished Justin.
I can't wait to see your project finished Justin.
yoothgeye
I build stuff.
Whitfield said:
The rear gearing from those PWs are what gives some good power I believe. As for the CDi ignition, I hear it's doable, but you lose headlight, taillight, etc... I wanna keep it more than just a day bike.
Re: Yamaha QT 50 "Noped" project
Why would you lose the lights going with a CDI?
Why would you lose the lights going with a CDI?
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Re: Yamaha QT 50
2 reasons, one is if you swap the entire wire loom the dirt bikes and quads were not equipped with lights, Two is because it will allow the engine to get up into higher RPM's producing more current from the magneto and it blows the bulbs unless you rebuild the wire loom with voltage regulators, resisters, and such.
dracothered said:
2 reasons, one is if you swap the entire wire loom the dirt bikes and quads were not equipped with lights, Two is because it will allow the engine to get up into higher RPM's producing more current from the magneto and it blows the bulbs unless you rebuild the wire loom with voltage regulators, resisters, and such.
