QT50 only goes 20mph?? I need help!

My 1987 QT50 for some reason only goes a pathetic 20 mph. When I first bought it, it would go about 30-33 mph. I've done all the maintenace stuff but believe the problem is in the muffler/exhaust.

I recently unclogged the carboned-up muffler which helped some. I talked to some guys in the shop and they recommended drilling a few holes in the back of the muffler right above the little exhaust pipe to help more air escape. Does anyone think this will help with gaining a few more mphs? Any ideas/suggestions? Thanks guys.

Re: QT50 only goes 20mph?? I need help!

i wouldnt suggest drilling holes in the back of your exhaust unless you heard so from a professional, it will be louder and might not even do anything. if you said you had it going 30 before then i would suggest decarbonizing your exhaust and cylender and cleaning your carb and a new plug, make sure the brakes arent hitting either.

Matt

Re: QT50 only goes 20mph?? I need help!

on my 77 batavus

i took the end of the exhuast off

like the baffle

it increased the power alot

but it is really loud!!!

Re: QT50 only goes 20mph?? I need help!

If you take the exhuast of its goes way faster, with noslowing down but i couldent try expereinmenting that much because it sounds like a weedwacker, and the loudest speakers in the world.

How did you clean out the exhaust?

Re: QT50 only goes 20mph?? I need help!

Hey there! I have a Cimatti city n=bike and hasve the same problem. (did) I chanfged the plug make sure the plug gap is good. You can get a kit for it depending on the type of bike you have. What do you have? You can get a performance upgraded kit to make a 65-70 cc kit to make it faster. I am in Vancouver Canada, and order the parts threw Steve's Moped in New Jersey. 1.201.384.7777. give me you email and I will keep in touch in case I need help too. I am working on getting an exhaust custom made for the bike. As you know or may not.. the 2 stroke engine thrives on exhaust therefore the one thing that should be modified is that. It will cost a few bucks, BUT it will increase hp from say for ex.. 30 mph to 55-60 mph. ow THAT is worth the money, do you think? Anyway I will await for your e-mail and talk to you later.

Duane

Re: QT50 only goes 20mph?? I need help!

Hey Duane,

I've just replaced the plug so thats not the problem. Like I said, its something with the exhaust flow. It simply needs more area to escape I think...anyways my email is djbconn@hotmail.com. Oh yeah, my bike is a 1987 QT50 50cc.

Re: QT50 only goes 20mph?? I need help!

HI BRI

if you want to decoke the exhaust.use caustic soda,

(drain cleaner) .remove the exhaust,put a bung in the

end,pour caustic soda in, stand it upright and leave overnight.

worked on my sa50 passola(u.k)

good luck

Bri...

Re: QT50 only goes 20mph?? I need help!

HI BRI

if you want to decoke the exhaust.use caustic soda,

(drain cleaner) .remove the exhaust,put a bung in the

end,pour caustic soda in, stand it upright and leave overnight.

worked on my sa50 passola(u.k)

good luck

Bri...

Re: QT50 only goes 20mph?? I need help!

Thanks for the draino idea Brian and thanks to all the others for their imput. I will try the drain cleaner thing and repost the results. Thanks for the help.

Brian

Re: QT50 only goes 20mph?? I need help!

Hey brian (nice name)

did you ever try that drain cleaner idea? my qt seems to be doing the same damn thing...

Does yours sound fine till about 20 mph, and then it engine sounds like it running rich, and flodding? thats me... and the carb is clean... the plug was clean (last I checked, before the problem got real bad) the exhaust on my '80 QT50 looks orginal, so thats my current hot lead...

Brian wrote:

>

> Thanks for the draino idea Brian and thanks to all the others

> for their imput. I will try the drain cleaner thing and

> repost the results. Thanks for the help.

>

> Brian

Re: QT50 only goes 20mph?? I need help!

Hi,Bryan! Only one caution about the Caustic Soda(that's LYE).Keep it away from any aluminum or magnesium,IT's DEATH to those metals.And wear goggles and have some water handy just in case you spill or splash it onto yourself,O.K.?

Re: QT50 only goes 20mph?? I need help!

Throw a new piston and rings in it. You will probably find the rings are melted to the lans on the piston. Remove the cylider and head to check, you'll need a new cylinder base gasket and should replace the head gasket as well, if you can't find parts then just make a new base gasket and reuse the copper head gasket

Re: I want to buid/buy 6 custom chopped mopeds

David M. Becker /

I want to find a quality custom builder for mopeds. I have 6 new yamaha "vino" mopeds with the "Jog" motor, (they look like retro vespa's) I want them made into "choppers" or will supply just the engines for full custom bikes. Can anybody steer me to a builder, America or Euro.

Re: Moped Choppers

David M. Becker /

I want to find a quality custom builder for mopeds. I have 6 new yamaha "vino" mopeds with the "Jog" motor, (they look like retro vespa's) I want them made into "choppers" or will supply just the engines for full custom bikes. Can anybody steer me to a builder, America or Euro.

Re: QT50 only goes 20mph?? I need help!

Same here, I have put new rings in + new gaskets + even a NEW exhaust damn thing still won`t go past 20 mph !, could the problem be electircal would an old battery that can`t give power cause this problem any ideas anyone ??

Re: QT50 only goes 20mph?? I need help!

Hey Bryanb, thats exactly what mine sounds like....runs fine until about 20 or so then sounds like its just flooding out or something. Everyonce and a while it 'catches' and I cruise at like 30mph and then it drops back down to 20 in a few seconds.

I haven't found the time to do the draino thing and I'm beginning to think maybe the carb just needs tweaked or something. It sounds like other people are having our same damn problem. Anyone who fixes this prob., pls post. thanks

Re: QT50 only goes 20mph?? I need help!

Hi,

this baffles me as well, my qt50 used to toot along at over 30mph bu now i`m lucky if i get mph out of it !, up to now i`ve done the following :-

put new exhaust on

stripped cylinder replaced piston rings

replaced all gaskets

replaced spark plug

topped up battery with water

and you guessed it still no more than 20 mph !!

I think problem could now be in electrics somewhere, I just can`t get the flywheel off to get at them, does the qt have a set of points that can be adjusted ??

if you find out anymore please post, i`m not giving up on this one, i`ll cure it if it kills me !!!

regards

John (Great Britain)

Re: QT50 only goes 20mph?? I need help!

are you geting spark try looking at the coil

QT50 only goes 20mph?? I need help!

take off muffler and carefully scrape off carbon at Head,spray WD40 inside hole then kick it over a few times with kill switch on or take off spark plug wire. Plug muffler with a potato and fill with kerosene.Drain next day and blow it out with compressed air.Also drill hole in the back of the black air filter box.

Re: QT50 only goes 20mph?? I need help!

holy old thread, lol.

Re: QT50 only goes 20mph?? I need help!

lol 7 years?

Seriously?

Re: QT50 only goes 20mph?? I need help!

lol since its here. lol anyone ever find the cure for their qt

Re: QT50 only goes 20mph?? I need help!

Not sure if this problem has been solved by poster but I have a PA50II and had the same exact problem would hit 20mph and it would bog down tried everything metioned here and nothing nothing , and found if i took the air filter (little peice of sponge ) out BANG was hitting over 30mph ever since believe that has to do with jets and air feul ratio don't know how to fix it but take the air filter out, mabee not the best idea but solved my problem....

Re: QT50 only goes 20mph?? I need help!

I would consider running this on a mixture of 50% petrol and 50% thinners i run my aerox on this mixture and have noticed increased acceleration and more top end speed.

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