Yamaha QT50 questions from a newbie (long)

david f martin /

Hello new friends...

I bought this bike just a couple of weeks ago. It was pretty much complete, only missing an aircleaner. It has a windshield, saddlebags and a lockable trunk. It is a very retro style, which suits me... It ran like a top before I started playing with it...

I searched this site and mopeds.org, trying to figure out what model I had. Then I took it to the Yamaha dealer, who told me that it was a Towny (MJ50). I ordered an aircleaner for it, which fit like it's supposed to, after I had to reroute some cables (previous owner, I suppose). Research on the MJ50 yielded very little information, but I was surprised to find that is has a 2-speed gearbox. The shop manual for the MJ is no longer available from the dealer.

Mounting the aircleaner (and messing around with the cables), I got the carb settings all screwed up. The machine starts easily and accelerates well, but bogs down at about 75% throttle. Plus, it didn't seem to me that it was actually going through 2 gears. On top of that, I found that the cable housing for the rear brake was broken, causing the rear brake to stick after deployment.

So, I took it back to the dealer and ordered a new rear brake cable. The mechanic there did some quick adjustments to my carb, commented on my brakes. I asked him about the 2-speed gearbox, and he suggested a new clutch. I decided to do some more research.

Browsing thru this website, I discovered pics of the QT50, which look exactly like my bike. This is good, I think, because there seems to be a lot more info on the QT than there is on the MJ.

Finally, here are my questions...

What is causing the bike to bog down at 3/4 throttle?

Does the QT have a 2-speed gearbox like the MJ (they seem to be very similar)? Would a worn clutch cause the bike to skip low gear?

There seems to be a lot more QT's out there than MJ's, so hopefully the manual for the QT is still available thru the dealer... I'll check on that tomorrow.

Any info on this bike (pics and stories, too!) would be very much appreciated...

david f martin

Re: Yamaha QT50 questions from a newbie (long)

david f martin /

Oops, I forgot to ask... Has anyone ever done any performance mods on one of these?

david

Re: Yamaha QT50 questions from a newbie (long)

you can add performance to the qt50 much the same way as the pw50 go to peeweecycle.com for infodavid f martin wrote:

>

> Hello new friends...

>

> I bought this bike just a couple of weeks ago. It was pretty

> much complete, only missing an aircleaner. It has a

> windshield, saddlebags and a lockable trunk. It is a very

> retro style, which suits me... It ran like a top before I

> started playing with it...

>

> I searched this site and mopeds.org, trying to figure out

> what model I had. Then I took it to the Yamaha dealer, who

> told me that it was a Towny (MJ50). I ordered an aircleaner

> for it, which fit like it's supposed to, after I had to

> reroute some cables (previous owner, I suppose). Research on

> the MJ50 yielded very little information, but I was surprised

> to find that is has a 2-speed gearbox. The shop manual for

> the MJ is no longer available from the dealer.

>

> Mounting the aircleaner (and messing around with the cables),

> I got the carb settings all screwed up. The machine starts

> easily and accelerates well, but bogs down at about 75%

> throttle. Plus, it didn't seem to me that it was actually

> going through 2 gears. On top of that, I found that the cable

> housing for the rear brake was broken, causing the rear brake

> to stick after deployment.

>

> So, I took it back to the dealer and ordered a new rear brake

> cable. The mechanic there did some quick adjustments to my

> carb, commented on my brakes. I asked him about the 2-speed

> gearbox, and he suggested a new clutch. I decided to do some

> more research.

>

> Browsing thru this website, I discovered pics of the QT50,

> which look exactly like my bike. This is good, I think,

> because there seems to be a lot more info on the QT than

> there is on the MJ.

>

> Finally, here are my questions...

>

> What is causing the bike to bog down at 3/4 throttle?

>

> Does the QT have a 2-speed gearbox like the MJ (they seem to

> be very similar)? Would a worn clutch cause the bike to skip

> low gear?

>

> There seems to be a lot more QT's out there than MJ's, so

> hopefully the manual for the QT is still available thru the

> dealer... I'll check on that tomorrow.

>

> Any info on this bike (pics and stories, too!) would be very

> much appreciated...

>

> david f martin

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