MOPED ARMY

Thanks, what sizes would recommend?

I thought 25 was low. I weighed 190 at the time. I’ve lost weight since (170). What is the average speed for a stock nu50 with 190lb person? The mechanic is also cleaning out carb and replacing o ring in the carb. The stock belt was very wore out as well. Not sure I had the right oil I was using 10w 40 that I thought I read in the manual was correct. Mechanic has replaced with two stroke oil. Air filter looked in bad shape as well. Don’t think it makes a difference but battery was dead as well and that has been replaced. There was a good bit of oil around the carb and hoses. Could these factors be responsible for the low speed? Anything else I should check? (edited)

manual

Make friends with the manual. It has a great section on basic maintenance. Don't waste money on a mechanic.

Ask what belt went in. Closest one to stock is an AX31. I haven't tried the Malossi belt on the Treats site yet.

Before you try the adjustments for performance that you'll find in the MA wiki, get it running well stock first.

You should be running close to 30 bone stock.

Yeah I don't think they run as well on regular oil. It doesn't mix well with the gas for one. My buddy did it for awhile. His bike survived. It doesn't burn as easily or cleanly for two.

Not sure why he couldn't get the yellow spring to work. It should work fine. Your mechanic may have little 2 stroke experience, let alone Urban Express experience.

The bx31 will kill your takeoff unless you add a thin washer next to the boss but that will hurt your top speed. I would stick with an ax31 belt. The bx will leave you a sitting duck in oncoming traffic as you try to accelerate from a stop. You'll need to tune your variator probably somewhere between 30 and 33 gram range give or take a couple.

Every bike is different due to varying degrees of maintenance over the years but 90 would seem to be a bit rich on the main jet. Too rich a jet and your pipe won't hit and your acceleration will suck as will your top speed. Get a range of jets down to 80 and work your way down with help of temp gauge and your ear and your feel.

Run premix is my thought as well. (edited)

Im gonna be "that guy" here, but have you considered selling it and buying a faster scooter? Typically the more you mod a moped the more quirks they seem to get.

I say scooter because while the NU50 has the heart of a pedal-less moped it still is licensed like any motorcycle or scooter in Ohio... where a pedal moped is classed different. Your state might be different so perhaps you need to stick with mopeds in which case i would recommend you just get it running right stock and enjoy (maybe stock-ish mods). I fear you will trade performance at the sake of longevity in this case.

30-35 reliably is well within reason for that bike with only light modifications

Nothing

Got the gates ax31 and a yellow rear contra spring for the gy6. I accidentally got the the yellow variator spring. Pre mix sounds pretty straightforward. If I get in time will give to mechanic if not will try to add myself. Looking for weights now to get closer to 30-33. Thanks everyone. Will update when I get some results.

Whats a good pipe to go with a stock cyl?

The stock belt was very wore out as well

Define wore out? Was it cracked or shreded?, or was there lots of black dust coating the insides?

There was a good bit of oil around the carb and hoses

That happens when people over-fill the 2t resevoir, use a funnel, and pour slowly. The flat-Earthers around here will say to ditch the oil injection. I say keep it, and keep it filled. If you can't keep it filled (even with a warning light) then maybe you should pre-mix it. Get it going over 30mph, before wasting money on a pipe. A pipe will be better for ya, when the bike is tiptop already. Lipstick, pig, get it?

Do a compression check, and learn to read a plug. (I assume a temp gauge was already mentioned)

https://www.mopedarmy.com/wiki/Plug_chop (edited)

do u have a torque wrench?

flank drive sockets/ box end wrenches?

a tear down manual?

if it was my bike & i needed it, i'd decarbon some of swamp off the combustion chamber.

or you could carbon seize later.

This is the manual I’ve been using.

https://www.manualslib.com/manual/1141067/Honda-Nu50.html

I have several regular tools. Socket wrenches, screwdrivers etc... but I definitely need to get some of the specialty tools to test temp, compression, etc... any reccomendations on where to find those tools for reasonable prices?

Bike has 3274 mileage showing.

Mechanic hasn’t opened engine to check carbon build up (said he didn’t have gasket). I planning on spending some time researching / learning this weekend.

Last thing mechanic mentioned was liner in gas tank was falling apart, lots of rust etc... He said it could be redone with 40$ kit. Is that worth it or should I look for replacement?

Always use Bluetooth wrenches on it, Recommended by the manual.

https://www.mopedarmy.com/forums/read.php?6,4258948