82 NU50 Modding total noob with Mechanic

I’ve got a NU50 (was getting max 25) wanted to get 35-40 to keep up with neighborhood traffic and a few turns on major streets. After research (mainly this site and treats) I found an mlm circuit (or Proma pipe with mlm suppressor) with header wrapped. I ordered a 90 jet, a bx31 belt, gy6 clutch, red malossi springs, and yellow contra spring. My mechanic is installing relunctantly and seems to be able to get everything done but he couldn’t get the yellow contra spring to work with the clutch so he used the stock spring with the gy6 clutch. 1. Do you guys think this set up will get me what I’m looking for speed wise? 2. Will the yellow contra spring make that big of difference? 3. I also got a new stock air filter but I concerned it won’t let enough air in. Any advice is appreciated. (edited)

Re: 82 NU50 Modding total noob with Mechanic

You usually want to buy a range of jets, it's not likely that you'll get it tuned right with just one option.

Re: 82 NU50 Modding total noob with Mechanic

Thanks, what sizes would recommend?

Re: 82 NU50 Modding total noob with Mechanic

Your bike should have gone faster to begin with and you should have sorted that out first.

Re: 82 NU50 Modding total noob with Mechanic

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)

Re: 82 NU50 Modding total noob with Mechanic

Never run engine oil as lubricant to be burned in the engine. And never use 2t oil as a gear lubricant. The gearbox in the rear uses gear oil or engine oil as the manual specifies. The worn belt could be the cause, as would a shitty air filter.

Re: 82 NU50 Modding total noob with Mechanic

Captain Janeway /

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.

Re: 82 NU50 Modding total noob with Mechanic

Thanks for the advice. Will for sure use 2 stroke oil going forward. Hopefully will have a good update soon. I will be maintaining from now on. Mechanic is $$. Is it very difficult to change jets? Will certainly get to manual more. (edited)

Re: 82 NU50 Modding total noob with Mechanic

Jack Rutherford /

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)

Re: 82 NU50 Modding total noob with Mechanic

Thanks for the Advice Jack, I certainly want decent low end I have a few short stints on roads with gunners. Would one of these belt work?

Gates AX31 Tri-Power Belt

https://www.amazon.com/dp/B000CRDM56/

D&D PowerDrive AX31 V Belt, Rubber, 1/2" x 33" OC

https://www.amazon.com/dp/B00NUR62IO/

Is it very difficult to set it up to run pre-mix?

Re: 82 NU50 Modding total noob with Mechanic

Jimmy Cincinnati /

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.

Re: 82 NU50 Modding total noob with Mechanic

I believe in GA it would be considered like any 49cc scooter and would require extra license / registration which is a big plus to me.

Mainly, though, I really like the aesthetics and comfort of this moped. They don’t make em like that anymore :)

I actually like the idea of tinkering with it as well and it hasn’t been that hard to find parts (Treatland FTW).

Certainly if I can’t get 30-35 reliably I would look elsewhere.

Re: 82 NU50 Modding total noob with Mechanic

> William Burgan Wrote:

> -------------------------------------------------------

> I believe in GA it would be considered like any 49cc scooter and would

> require extra license / registration which is a big plus to me.

>

> Mainly, though, I really like the aesthetics and comfort of this moped.

> They don’t make em like that anymore :)

>

> I actually like the idea of tinkering with it as well and it hasn’t been

> that hard to find parts (Treatland FTW).

>

> Certainly if I can’t get 30-35 reliably I would look elsewhere.

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

Re: 82 NU50 Modding total noob with Mechanic

Thanks that’s encouraging. Maybe the ax31 is the way to go for now (closer to stock which should give gains close to what I’m looking for). I also did ask mechanic to remove 3 of the 6 variator weights (not sure if he did). Would that need to be changed if I stuck with ax31? (edited)

Re: 82 NU50 Modding total noob with Mechanic

Nothing

Re: 82 NU50 Modding total noob with Mechanic

Jack Rutherford /

ax31 is fine.

1/2 the weights is 39 grams. its close but not perfect.

drain your oil and gas and then fill gas tank with premix at premix ratio somewhere around 40:1 - 50:1

Re: 82 NU50 Modding total noob with Mechanic

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.

Re: 82 NU50 Modding total noob with Mechanic

If you run premix in the tank, make sure you disconnect the oiler line from the intake and cap it off on both ends; cap the intake inlet nipple to prevent air getting in and cap the line to prevent leftover oil getting everywhere. Obviously empty the oil reservoir as well (or at least disconnect and cap the line running from the reservoir to the pump.)

Re: 82 NU50 Modding total noob with Mechanic

Whats a good pipe to go with a stock cyl?

Re: 82 NU50 Modding total noob with Mechanic

Downhill Harvey (OFMC) /

Vario weights, and belts, won't make a difference if you don't know the health of the engine. Top end should come off, and be de-carboned, with new piston rings, seals, and gaskets.

Re: 82 NU50 Modding total noob with Mechanic

Downhill Harvey (OFMC) /

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)

Re: 82 NU50 Modding total noob with Mechanic

Jack Rutherford /

> Rica Rivera Wrote:

> -------------------------------------------------------

> Whats a good pipe to go with a stock cyl?

I like that MLM circuit pipe on a stock cylinder. Had good luck with the qt50 version plus it gives you easy access to the rear tire.

Re: 82 NU50 Modding total noob with Mechanic

kevin Smellaflange /

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.

Re: 82 NU50 Modding total noob with Mechanic

Captain Janeway /

I also say keep the oil injector if everything's working ok. Leave that 85 jet in while you're working on it. get a new air filter.

Again, put it stock first then play with it. Lowering the weights the way you have should have help and yes, see if your mechanic put in new rings while he was in there. What's the mileage?

Re: 82 NU50 Modding total noob with Mechanic

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?

Re: 82 NU50 Modding total noob with Mechanic

Captain Janeway /

derust

Follow this. You should be able to get most of it out. As to the liner, I don't use it, mainly because I got one once where someone had done a crappy job putting it in and it was a pain to get out.

I've used evaporust and vinegar on mine (NOT together!).

Clean it and always keep a good inline filter on the fuel line to keep smaller particles out.

If your mechanic puts that stuff in without blasting out the old crud it just gives more problems. Double check what he's doing

Re: 82 NU50 Modding total noob with Mechanic

𝐿𝑖𝑘𝑎-𝐿𝑜𝑡𝑎𝑠𝑎𝑢𝑟 𝑀𝑒𝑔𝑎𝑝𝑢𝑠 🦖 /

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

Re: 82 NU50 Modding total noob with Mechanic

kevin Smellaflange /

bluepoint is SNAP-ON

Re: 82 NU50 Modding total noob with Mechanic

Captain Janeway /

Re: 82 NU50 Modding total noob with Mechanic

Downhill Harvey (OFMC) /

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