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Rolo Tomazi

Yamaha Nouvo 135 - how to give it a bit more power?

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I own a '09 Nouvo 135 and wonder if it's possible to make it run better. I've noticed a hose running from the muffler to some kind of pump which I'm sure is connected to the carb for emission reasons. I had the same on my XR650L and taking the plumbing off made the bike much more ridable.

Has anybody done this?

Since I'm going to take a closer look I wonder if there are other things that may make the bike run better, like a less-restrictive air filter.

For the XR650L I had to install a bigger main jet to make it run better at higher revs, I wonder if anybody has any experience with that.

I'm not talking about getting a bigger cylinder and piston, I don't want to spend that kind of money and end up with 170cc or so.

Any tips appreciated.

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Not sure why you would want it to run better, and never heard of any of those mods, but go ahead, try, and let us know.

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I've experimented making larger induction air tracts for my little 59cc bigbore Ruckus before and tried multiple carb jets but it was not worth doing.

I had an on board computer/dyno and after 10 repeated runs the bigger air intakes clearly made the bike lose power.

I don't recall if a cone filter helped or not.

A proper jet might help but I am guessing Yamaha probably chose the best size jet for the average atmosphere in Thailand.

Changes in the variator pulley weights can make the bike accelerate faster but limit top speed and vice versa.

You might also try to find an aftermarket CDI but it might be BS without dyno results.

Edited by ttakata
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Thanks, ttakata, I agree that often it isn't worth experimenting, that's why I left my Nouvo stock, and maybe it will stay that way.

But some bikes are choked by parts that are necessary to make the bikes pass emissions, especially when they still have carbs.

There are lots of Thai boy racers out there who know about making their 125cc scoots run faster, and there is a big aftermarket for these kind of bikes.

But I can't read Thai and don't know any Thais who I can communicate with in English.

Taking some "emission nonsense" off makes some engines run the way they actually should.

I don't want to start a discussion about caring for the environment, but it's kind of a joke when you see lots of pick-ups with 2500cc or trucks with V8 engines belching out black fumes all day and then have to ride a 135cc bike which is restricted because of Thai emission laws that are stricter than those in Europe.

Back to the topic: you brought up the variator pulley weights and I remember fixing up an old Nouvo 115cc. The mechs at the dealer took the new factory weights and drilled bigger holes into them without even asking me! It makes sense that lighter weights moving quicker in the variator lets the bike accelerate faster. That's actually a cheap measure a Thai boy racer would have told me if he could speak English! Maybe I have to find a garage around here and see what I can learn. I'm not much concerned about top speed, that's what I have a bigger bike for.

I was hoping that someone had already done this and could tell me what parts to use and what result was achieved.

Edited by Rolo Tomazi

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I was at a small shop yesterday buying something else and noticed in a display case a large selection of variator weights.

Never heard of 'drilling them out' before, as they are not expensive.

If I understand the mechanics of it, a drilled out (or lighter) weight would make you accelerate more slowly,

but I may be thinking ass-backwards...or is it bass-ackwards?

...dunno, gettin' dumber every day.

√-out this vid:

There is also something known as a "Dr. Pully sliding variator weight" for better performance.

In reality my NYE (a gas hog) was plenty quick.

I rarely used full throttle.

And as a friend observed:

the easiest & cheapest 'mod' for performance is to twist that thing in your right hand towards you more.

5 5

Edited by papa al

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I'd ordered stock weights from Yamaha because they weren't round anymore, then don't move outwards the way they should.

The mechs wanted to drill the center hole bigger to make them lighter.

Seems that if the variator accelerates faster there's more power at hand earlier; you could compare it to a heavy flywheel but this is of course in the transmission. The lighter weights may move outwards later, letting the engine spin faster.

Funny thing the guy in the video talked about first and second gear - a constant variable tranny does't have gears, as such, it's constantly variable.

The Nouvo 135 goes quite well, and when pushed, uses as much gas a CBR150R with FI which has at least 50% more power and weighs more. But I only use it to go to work and shopping, so I don't care if I pay 200 baht more a month on gas.

But a little more power never hurts, I have the time and like to fiddle with it. I'll try the lighter weights, at least they'll make me feel faster...

I had a closer look and realized that the hose from the muffler goes to some kind of valve, then to the air box, not to the carb, so plugging it off won't do any good.

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Yes, I think he meant the 1st and second pulley, not gears per se.

There are some reduction gears between the rear pulley and drive axel, but not the kind that can be shifted.

Happy fiddling....

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Nah, go to 2:00 where he's talking about "going into 2nd gear" and "staying in 1st gear longer", actually meaning high and low revs.

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Right. & the idea of CVT is ~constant engine revs in the power band.

V (for velocity) is a bit of a misnomer.

Angular velocity I guess.

Should be CRT. 5 5

Numerous YouTube vids are available explaining CVTs.

A most informative website.

Bye-the-bye, you look a lot like Kevin Spacey.

Edited by papa al

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Actually the V stands for "variable", meaning that the two pulleys constantly provide variable ratios, not like usual transmission where gears have a certain ratio.

Of course the avatar is not me - I wonder if you can make the connection between it and my handle. :)

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Got a Thai guy in Nong Bua Lamphu Province that can get as much poer as possible. Speaks enough English to get the point across. I have watched him port heads.

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Tinkering with the roller weights, without further mods is wasted time.

You will need a:

Big Bore kit

Cam

Variator

Carburettor

Here we go:

http://hispeedpiston.com/yamaha/thai/NOUVO135/index.html

yes, these mods are the best for more power on a nuovo and not so expensive IMO.

But more power needs more stopping power and maybe some braces for the chassis and better tires and suspensions. so going for the biggest bore up kit and a lot of power needs additional expenses so dont recommend.

Still, with a simple low stage/cc bore up kit, proper carb jetting, variator, a freer flowing exhaust and air filter, some better tires should be OK and i believe will not cost more than 10 k thb.

Edited by ll2

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Just get a variator weight a couple grams lighter and pull it in no need to drill as they could be off slightly and effect movement. This will increase acceleration probably at least 10 percent or likely around 15 or 20 percent in my opinion. It will not effect your top speed unless you put one in so light it will not allow the belt to slide but this won't happen with a couple grams lighter. This is by far the best mod and the cheapest too and probably the only one worth doing unles you want to piss away your money.

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Right, just a bit better acceleration in traffic to make up for my weight is all I'm looking for, I'm not interested in a higher top speed.

The Nouvo 135 took the same amount of gas at full open throttle my fuel-injected CBR150R took which has almost twice the power.

Lighter weights should do, unfortunately I couldn't find any for the Nouvo 135 in Songkhla or Hat Yai.

Lots of weights to choose from for other automatic scooters but none for the Nouvo.

I'll have a look the next time I'm in Bangkok! smile.png

EDIT: That hose from the muffler goes into the crank case, so it's not an emission thing, I decided not to mess with that.

Edited by Rolo Tomazi

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