QT50 Performance exhaust and jetting

Kyle Wagenknecht /

Hey everyone! I bought an '82 QT50 in March and have been tinkering around with it and got her running pretty good. I have a few friends with bikes and we ride together quite a bit and they are a little faster than me, so I decided to buy a performance exhaust =) and have a few questions about jetting and stuff once I put it on. First of all, does anyone have a QT50 with a MLM People's Pipe on it? Here is a link to it, I thought it was pretty sick and would be a good choice http://www.1977mopeds.com/product/50472

I want to know what size jet I will need to put in it to run it with this pipe. The entire bike is stock right now and this will be the only mod that will be done to it. Another thing I was wondering about is if I change the jet size, do I have to mess with the automatic oil pump or will it be fine? Any insight on these two things is greatly appreciated!

Re: QT50 Performance exhaust and jetting

ɯɐpɐ ʞunʞs /

Performance forum.

You shouldn't have to mess with the oil pump, it just puts in a small amount of oil for each RPM.

Re: QT50 Performance exhaust and jetting

Kyle Wagenknecht /

Okay thanks a lot! Thought maybe I would have to with the increased fuel flow.

Re: QT50 Performance exhaust and jetting

Mike Hagopian /

Just to be safe add a bit to the gas. I got rid of my pump completely, just don't trust the damn thing...let me know how the pipe is, I'm thinking about getting one for my 84 qt

Re: QT50 Performance exhaust and jetting

Kyle Wagenknecht /

Thats a good idea. I haven't had any problems with the pump or heard of anyone else having problems with it, but then again I haven't really researched it too much. I will let you know about the pipe when I get her on and jetted. Should be coming in tomorrow, then I just need to figure out what size jets to run and I should be able to let you know.

Re: QT50 Performance exhaust and jetting

ɯɐpɐ ʞunʞs /

Keep in mind that if you add oil to the gas as well as using the oil pump, you're putting in twice the amount of oil that you should be, which means you're going to cake up your pipe, spark plug, and cylinder head faster.

Re: QT50 Performance exhaust and jetting

Kyle Wagenknecht /

Yeah, I was probably just going to keep trusting the fuel pump. Hasn't done me wrong yet and I don't feel like pre-mixing the gas if I don't have to.

Re: QT50 Performance exhaust and jetting

Those pumps don't hardy never fail, they're adjustable and can run enough oil for any kit you put on it if adjusted correctly. Its just safer to run premix on a high reving engine of this type.

Only prob with the stock set up is it pumps to much on the stock bore, there's no need to mess with it for a piped stock engine.

Mill the head, open up the exhuast port or add a yt60 jugg, add pw50 gears and add a real carb w reeds and you'll like that pipe alot more

Re: QT50 Performance exhaust and jetting

I have some special springs for these little monster wheelie machines :)

drop me a email if you would like to get some springs for the clutch. It will have the hole shot/ off the line pull. (edited)

qt50springs.JPG

Re: QT50 Performance exhaust and jetting

Kyle Wagenknecht /

Thanks for the ideas guys. I don't want to spend a ton of money on it, and I wouldn't trust myself milling the head or exhaust port. I will see how I feel after the pipe and go from there.

Re: QT50 Performance exhaust and jetting

Aaron Gottsch /

I jetted my Qt to 75, put on a K&N filter and Boyesen Reeds and the MLM People's Pipe. The pipe made all the difference. The only down side to the pipe is the kick stand hits it when you are going down the road and it is putting a dent into the pipe. It would be nice if they would have welded a piece of thicker metal there to withstand the impact. I think I am getting low 40's but I have not used a GPS. Just this week I put on the new 38mm O-RING high compression head from Treats. I love it so far. It is much quicker than the old head. I hope this helps.

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