New Here By gbtr6 (Read 1,709 times)

[gbtr6]

Hi,

I am in Green Bay and just brought home my sons Yamaha QT-50 to work on. I do work on my cars, '67 Mustang and '74 Triumph TR6, but not sure on a moped. When it was running it ran well. It's been sitting a while because my son said oil was leaking into the carb. The carb is partly off. I imagine I should remove it and clean/rebuild it, as well as clean up all the engine.

Anything, tips, on other maintenance items to perform?

Thanks,
Perry

[Alleyoop]

I am assuming it is a 2 stroke, and oil does drip into the carb to mix with the gas. That is how it lubricates the motor. Just like your weedeaters you mix some oil with the gas.
If to much oil is getting fed there should be an adjustment on the cable. Usually the Throttle cable has a "Y" and when you twist the throttle it also pulls on the OIL CABLE so if to much is being fed then you length the cable so it does not feed to much oil. Shorten the cable and it feeds more oil.
ALleyoop

[mike6736]

Welcome .....

Magoo

[LUKE]

its pretty much a fuel system problem. make sure that the carb is clean inside, float is not stuck up., jets are not clogged., petcock is working fine. fuel filter is new. /
now, see if the spark plug is actually giving out a spark.
remember there are 3things needed for a motor to run gas+air+spark.
good luck!





it's full moon, i need to be serious tonight.

[Alleyoop]

Forgot one very important thing, you can have all 3, Gas+Air+Spark but if no compression all three will not help.
Alleyoop

[LUKE]

i quote:

"I am in Green Bay and just brought home my sons Yamaha QT-50 to work on. I do work on my cars, '67 Mustang and '74 Triumph TR6, but not sure on a moped. When it was running it ran well. It's been sitting a while because my son said oil was leaking into the carb. The carb is partly off. I imagine I should remove it and clean/rebuild it, as well as clean up all the engine."


he said the scooter ran well when it was running before it got stocked,there is no wear and tear when the scooter is sitting and not being used.
so, the compression is understandably out of the question. i'm just sayin'...lol ;D

but yah, as a general rule,your'e right Al,compression is a another issue to deal with, sorry, bear with me, i work mostly with liquid cooled, fuel injected japan scooters, with ECU and all that... carb with floats are basically new to me. but i'm learning little by little baby steps at a time.

[Alleyoop]

I did not say that was HIS problem I just added to your comment that for "A" motor to run it needs the 3 things. But for "A" motor to run it also needs to have descent compression and if any of the mentioned is out of wack it may not run or it may run but badly.

Yea sitting for a long time a motor can create problems on its own the rings can get frozen or rusted in their slots and you will have a completely different scoot from when it last ran. They all work same way whether it is liquid cooled with EFI and ECU that controls the mixture doesn't matter they all have rings and all the 4 bangers have valves that can leak.
Alleyoop

[Bashan]

Hi Perry, welcome to the forum. Don't mind them, they fuss at each other all the time, (if you kids can't play nice go out to the garage). Hey, I have gas but I can't seem to start, I think it was the tacos.

Once again Alley is right, the mighty QT-50 is a 2T. It's also a cu-tie (ba-dump):

Hey boneheads, ^ckick the pic^ and learn something....and quit arguing!

Did you guys see this thing has a shaft drive! Easy now BMW...

Here's the mighty powerplant juiced up to crank out an incredible...um 2 HP... :

If you need anything around the forum Perry send me a PM.

[gbtr6]

Thanks for the warm welcome. I appreciate it. Nice to see spirited discussion. I understand the basics, but still like to know some of the tips and shortcuts everyones learned on these things. I've been around carbs and points ignition with the TR. Changed that to a Pertronix pointless ignition.

Be interested to learn the hop ups for this ped also.

Thanks,
Perry

[LUKE]

youre very welcome gbtr6ex!! next time just pm me and we will make your scoooter run in no time.




ugh!

[mike6736]

Wow that is so cool a drive shaft on a little thing like that....

Magoo

[gbtr6]

Hey Bashan, what mods have you made to the engine in the picture? I am going to get the K&N type filter. I need to flush the gas and oil tanks, What would be suggested? The gas tank smelled like turpentine, so I know some cleaning is in order. The whole engine is dirty and oily so I'm going to Gunk it and wash it. I think I'm going to need a battery too. I tried to charge it, but it didn't register on the charger.

Perry

[Medman1952]

I happen to have one of these little guys, I also have both the service and owners manuals in digital form if you need it, I don't come around here a lot but Alley knows how to get my attention if you want those manuals.

Eh here are the manuals

Wiring Diagram

Owners Manual

Shop Manual Part 1 of 4

Shop Manual Part 2 of 4

Shop Manual Part 3 of 4

Shop manual Part 4 of 4

I found all those on the moped army site, very difficult to navigate that forum but if you stick with it they have a lot of good info.

You can get a 60cc big bore kit for these and I understand it really helps them. I have no idea what was done to that one but you might consider a spacer under the reed valve.