Scoot won't climb hills

x2.
Takes more than wanting/wishing and hoping to get torque/power out of a 50cc scooter, even more so with a CVT. Kinda one of those "right tool for the job" things.

I am 50lbs lighter than the OP but my SR will pull from a stop up a steep hill to 40mph indicated without issue. His bike has considerably more tuning potential.

It's 50ccs, but so is my moped, and it climbs just fine. I believe it's because the mopeds first gear has a much lower ratio than what is available on a stock CVT. Both my 50cc scooters would hit 40 mph, the moped only goes 30 mph. And I am pretty sure that both scooters had more than 2 hp. The lower gear gives the moped more leverage. It's amazing what 2 hp will do with low enough gearing.

It does make sense that an aftermarket variator with the right design would go a long way toward helping the scooter climb by keeping the engine rpms up while climbing. I have very little doubt that a 50cc scooter is capable of climbing almost anything, if you can get it's full power to the ground.

Scooters do seem to be optimized for urban use. But I wonder how well a 50cc scooter would do in San Francisco.

Not so well in San Francisco. When I lived there while I was going to college I decided to buy a motor scooter to get around easier. In those days you could park on the sidewalk. In fact one day I had just parked in a car space and a cop walked up and said, "Get that scooter outa there. You're taking up a car space. Put it up on the sidewalk. Right here." He pointed to a suitable spot, so I did.

So anyway, when I went to buy a scooter the dealer said, "Forget the 50cc models. They can't get up the hills." He pointed to a Lambretta, which I bought. I can't recall the engine size but it was somewhere in the 150-200cc range, and of course it was a shifter. I had no trouble with hills.

Back in the '70s, pedal mopeds were the big thing. You could get many models with either a single speed or a 2 speed engine. The single speeds were fine for level roads, but would not climb. Pedaling was not much help, because the pedal drive was geared so low. If you needed climbing ability, a 2 speed was the way to go. When you encountered a hill, and engine rpms dropped, it would shift into first gear, and the engine rpms would go way up. In first gear at 10 mph, the engine would turn about the same speed as it would at 30 mph in second gear.

Mopeds are a fun ride. My 2 speed Puch will climb anything given enough time. You ride them like bicycles, on the shoulder. They are not legal on freeways, but there are a number of non freeway routes that will get you across the U.S. It's kind of like traveling by bicycle, except that you don't have to pedal. I used to do a lot of traveling on a moped, and passed quite a few bicycles. I remember feeling great about how I didn't have to pedal. Those old '70s mopeds had to be decarbonized quite often, you had to mix the oil and gas, and more than once I had to stop on the side of the road and adjust the points. I liked them so much that a few years ago, I bought a vintage Puch 2 speed. I would love to take a long trip on it, but I'm not 20 years old anymore and they are not very comfortable.

This has gotten way too complicated! Try lighter rollers first. It's fast, simple, and cheap. It may solve your problem, and you won't have to overthink all this other stuff.
FWIW, I had a 50cc Zuma that climbed great, and we have some pretty steep hills in Ohio.

Your rollers are way way way too heavy, and the contra spring is probably not helping you either.
Lighter rollers go up faster because they require less energy to move, but the engine needs to have more power to get them up as far as they can. Once the engine gets going , heavier rollers will go up farther, to the point the engine has the power to make them go up further. But manufacturers also put in heavier rollers because they protect the engine by limiting how far it will rev up. That's why you can't put 18 gram rollers in and go 65 mph. Try the 5.5s, then 5s. The 1000 contra spring (white) should be like the stock one in terms of making the clutch work, and won't change the performance, it just doesn't fade under hard use. If you are using the yellow one, that's probably a lot of your problem. For what you are doing, I would recommend trying the stock contra spring again. You are going to have to do some switching back and forth to find what works best.
if you got an aftermarket belt, and if it's longer than the OEM belt, you might want to try a belt that is the original length. Longer belts, heavier contra springs, and taller rear end gears are good once you get significantly more power out of the motor than a stock little 2 stroke is going to make. You want the setup that gets that engine into the powerband and keeps it there. The red clutch springs are not ideal for what you are doing, the yellow 1500 rpm ones are better, but the red ones are better than what they replaced. The issue is that they will cause the clutch to engage a lot harder, and you aren't going to get a lot of life out of the belt. It will be particularly noticable in traffic.
Check the exhaust at the neck and make sure it doesn't have any sort of restrictor, and make sure there isn't a restrictor in the cdi.
It sounds like you are not allowed in this competition to put on a 70 kit and full race exhaust, so there are a couple of tricks you can do to get a little more out of the engine. If the exhaust is one where you can do it, take a long steel rod and hammer through the exhaust from the tailpipe as far as you can. You want to knock out or bend the baffles, open it up and make it act a little more like an expansion chamber. If it sounds like a dirtbike, it worked. If the rules allow you to get an aftermarket exhaust, by all means do so. If you can find a used MHR, PM Tuning, Yasuna, Polini high end racing pipes, that's going to be best, but any of the Leo Vince, Tecnigas, etc, ones is an improvement. Try to get one that is not homologated. An expansion chamber does to a 2 stroke what a supercharger does to a 4 stroke, and is usally good for 5-7 mph on an air cooled 50cc 2 stroke. As far as rejetting, wait and see. If you put a pipe on, you may or may not need to. Most manufacturers set the bikes up slightly rich, again so they don't seize being run wide open from day one. The Leo Vince pipes for 50cc scooters come with 4.3g rollers and yellow clutch springs, to give you an idea of where you should be thinking to get the maximum performance and speed out of that little motor. Check under the reed block for any sort of restrictor as well. If there are restrictors in the reed block or exhaust, you will have to upjet when you remove them. Go up 4-5 and you should be fine. If it's not better, take it back to stock.
Also, put some 2 sttoke oil in the gas, even if you pre-mix. That leans it out slightly, and protects the engine as well if you are going to be riding it wide open all the time. If you have the time and desire, you can either mill the head or find a thinner head gasket and get what is called the squish zone down to .9mm or so. That will give you a bit more compression. Take the top end off and completely decoke the cylinder, piston and exhaust port, and open up the exhaust outlet a bit with a dremel. they are usually restricted on 50cc scooters where they meet the manifold. If the previous owner used cheap oil, and the bike has more than 4000 miles on it, there could be a significant layer of carbon blocking the exhaust port. Scrape it out and then polish the exhaust tract from the port to the manifold with a dremel. and the motor will run a whole lot better. Don't play with the ports, unless you either know what you are doing or are allowed to replace the jug if you screw it up. A carbon fibre reed will also help a bit too, especially if the metal reed is fatigued from age and mileage. Like everything else for this project, get good quality but the basic one. Don't get the stiffest carbon reed out there, get the one that is marketed as a better replacement for the OEM one. Malossi has a lot of parts like that, and if I know what your parameters are, I can go through the catalog and pick out a few things that mihtg give you a slight advantage over the rest of the pack.
If the motor is in good shape, and you switch rollers to 5 grams, and put in the stock contra spring, you will be able to stop and start going up hill. You are not going to set any world records though. As far as top speed, you may or may not see an improvement. it really depends on how much power the engine makes. Changing out the gears is usually done to make the high performance engine turn slower at higher speeds, and you are trying to get this thing up into the powerband and keep it there, which is crucial for 2 Strokes, so they won't help you.
In riding this thing for 50 miles at a stretch, you want to do a couple of things, don't run wide open, you will get to top speed and be able o back off a little and maintain your speed. That richens the mixture, and cools and lubricates the engine better. Going down hills, don't let off the gas. When you cut the gas, you cut the lubrication to the top end. If you have an adjustable premix pump, set it so it is always open and open all the way at wide open throttle. Usually they aren't. If there aren't rules about it, run a good pure synthetic ester two stroke oil like Motul or Amsoil. If the weather gets hot, Kawasaki has a 40 weight 2 stroke oil that is good in premix applications to give you a little added protection. You can mix two stroke oils. It doesn't matter.
Run your tires at 42-44 in the back and 38-40 in the front. Going from the recommended 28-32 to that will pick up about 2-4 mph. Get a tire that you can run at a high pressure, according to the tire, and run it at that. If you can, get the cheapest chinese scotoer tires you can, as long as rain and corners aren't an issue. They are hard and durable and made of nylon. and if they go flat, they are so hard that you will still be able to ride for a while without breaking the bead. But they handle like crap in the rain and corners and metal bridges. Ideally, you want the tallest, thinnest tires you can put on it. Less rolling resistance. Put a light synthetic motor oil in the rear end, again slightly less rolling resistance. With something like this, you are looking to pick up every minute advantage you can. put a few of them together and you have another tenth of a horsepower, another mile an hour.
I don't know what it is like in England, but the 50cc scooter racing scene is huge in Italy and Spain. There are races where they are limited to 50cc. Thanks to the internet, you could probably find someone who tunes 50cc racers that wouldn't mind giving you a bit of advice. Airsal, Malossi, Polini and just about everybody else makes very high end 50cc racing top ends. If you find a dealer for one, you've either found someone who can give you a lot of help, or they can tell you who buys the $400 50cc kits. That's the guy you want to talk to. Even if you can't install the kit, they can tell you how to make your scooter go faster. As far as people who really know two strokes and performance, Cortez has the most real world experience, and can probably give you excellent advice.
I know this sounds like a lot, but if you get the right parts, and have a good workspace with proper tools, it's about six hours of work total.

Thank you very much for some comprehensive advice. I didn't manage to look at the bike at all over the holidays but will start to experiment next weekend.

I take on board all of your advice and will persevere until I beat that hill. As suggested it is likely to be a compromise with some top end being lost.

I don't expect to win any prizes on this challenge, it has become more of a personal vendetta to beat that hill....

I'll keep you all informed on my progress with the final set up listed.

Regards and Happy New Year


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Scooterpartsco,

Seeing some poor advice in that mile long post.

Running excessive pressure in the tires is foolish and not going to gain anything going up a hill. The speeds he will be able to reach will be HP, tranny config, and gross weight dependent. You are advising him to decrease traction in a landscape with wet roads, turns, and hills.

Second, each aftermarket pipe will come with different weight rollers and clutch springs dependent on application. That is if he has the stock variator for them even being applicable. His bike having 8g rollers, the only 2 stroke 50 having that heavy of a weight that I know of is a Morini Ditech. If that were his engine, a 5.5g rollers set will have that motor needing a rebuild in no time.

To the OP, do you know what engine is in your bike yet? It would be helpful.

Aftermarket variators such as my Malossi Multivar 2000 require heavier weights than stock by more than 1.5g.

A race pipe is not the answer for an engine with a stock cylinder. Recommending an MHR pipe is a bad idea unless the OP now has at the very least a sport cylinder.

Scooter parts sellers will be doing big business with your advice.

Chips, thanks for spilling the beans on this site and thread........

ZXRWoody is also part of the scooter challenge with Chips. Lots of great advice on this thread. I couldn't believe the enthusiasm - 4 pages!!

I bought a Speedfight 2 as a non runner from ebay, yep I can hear you all groaning. After a lot of effort but fortunately small expense the beast runs.

The mighty Speedfight affectionately named Pug-Ped is booked in for a road worthy test tomorrow and on the way to the test station are a couple of hills, into and out of a stream valley. I'll let you know if the mighty Pug-Ped can pull me out of the bottom.

Could be an embarassing push out as I am a similar build to Chips!

It's a standard beast apart from an imobiliser bypass which apparently incorporates an unrestricted CDI. It also has a 'carbon effect' end can which Chips' Speedfight doesn't .

I have strong expectations of having to adjust springs and weights myself to achieve some kind of performance on hills. It's a balancing act because we also have a drag race, fastest Ped and off road activities.

I'd recommend something like this if you work with a group of like minded colleagues - the team building this has brought to the office far outweighs any corporate event I've attended.
Lots of chat developed as we all have bigger four stroke, geared bikes and when components from CVT strokers come into the office it produces huge interest.

zxrwoody

how steep a hill ? I have ridden my GFs 50cc Chinese no name scooter up a half mile long hill that averages 15% and hits 18% for a few hundred feet, granted, it slows right down.

LIGHTER ROLLERS GO UP SLOWER!!!!!!!!!
After seeing an opening statement that they go up faster, I would be skeptical of any advice scooterpartsco gives.
Heavier weights= more centrifugal force.

I'll just add that there WAS a restriction in the SF exhaust that has to be
cut off and welded, but no CDI restriction.

Because they are lighter, lighter rollers require less mechanical energy to move, and they allow the engine to get to a higher rpm faster, so they move quicker because the engine revs up faster. But unless you have sufficient power in the engine, they won't go as far up the variator. That is why if you put light enough rollers in just about any scooter, you can get it to wheelie. Heavier rollers will give some top speed advantage, as long as they are light enough that the engine can pull them up the variator, too heavy and they don't launch well or go high up on the variator, that's why you can't put really heavy rollers in your 50cc scooter and hit 65 mph. The OP is having problems because his rollers are too heavy for the scooter to launch under the load he is likely to find in this competition. A two stroke is all about powerband, and lighter rollers allow it to get there faster and stay there.

It's obvious from this and many of your other posts on this site that buying a fast scooter, bolting parts onto it, and reading forums over at af1 does not make you an expert in two stroke performance. The scooter has a Peugeot engine, not a morini, minarelli or piaggio. It came stock with 9 gram weights, and was speed restricted when new. One of the ways they speed restrict scooters is with overly heavy weights. He is trying to get the most out of it for a short period of time, hence the suggestions to tune it for the maximum performance you can get out of a little bike like that. Overinflating the tires will give him extra speed, hence, good suggestion. The bike doesn't make enough power to take advantage of a yellow contra spring, hence it is a good idea to take it out. You should go back to the thread where you were explaining to Cortez how every dealer in Europe did not know how to set up a Ditech right. You sounded like an authority there too.

Peugeot did not use rollers that are too heavy to restrict the top speed,
and that's not a good approach anyways, since they'll restrict acceleration
more then top speed that way.

The Speedfight had a restriction in the exhaust that is easily removed
and welded shut, and in the CVT, which the OP here obviously removed
since that one limits the scooter to 35mph or so.

The SF2 that I owned could do over 55mph indicated with the Leovince ZX
exhaust, and NO OTHER mods, it was just derestricted, had stock weights
and springs.

We have no hills 30-35 miles in any direction from the city I live in so I
didn't have to tune it for climbing, but I see people climb hills on chinese
4 strokes that half less then half the power of the SF so I assumed SF
should have no issues climbing any hill.

They use a heavier roller than they would if they were looking for it to perform at it's absolute best. By design, OEM roller setups tend to keep the bike from hitting the top of the RPM range. The OP is looking to do a lot with this scooter, from touring to off-road to a drag race, and it has a very small engine and a much narrower powerband than 4 strokes. In addition, for him to do what he wants to do, he needs to get it into and keep it in the powerband as much as possible. For the road, he should find the roller weights that give him both the start and stop hill climbing he needs and the ability to ride it 50 miles. He has a bunch of different weights, and the easiest way to get it to climb hills is to use the 5.5s or 5s. If they are too light for the long stretches, then he needs to find a compromise. Given his size though, it's going to be a lighter weight than for someone who weighs 100 lbs.

I am glad Cortez had one of these bikes to provide first hand info about it. You keep throwing out information that is only applicable to air cooled Zuma's or Chinese 2 stroke clones and not the OP's bike.

You should stick to first hand information and not reading some forum. Less misinformation will be spread that way.

Better yet, put up a link to owners who have went from Cortez' indicated 9g stock rollers to 5 or 5.5g roller weights trying to blow their engines, genius.

While you are at that, could you please stop posting about a Keeway in the Honda thread. Thanks.

Sorry OP. Hopefully you get at least some entertainment value from this. Highly recommend you find a forum dedicated specifically to your bike where you can mine data from owners or experience so you don't damage your bike.

Getting the best balance of acceleration and top speed for the style of riding/ terrain/load one puts their bike into is a dark scientific art of mechanical alchemy as far as I can tell....... but I've got some basic ideas.

From my understanding, it's all a complicated dance as to how the variator and its wieghts, clutch spring and available HP at given RPMs all work together to move the bike. Changing these elements around affects how quickly it accelerates and how effiectively it is able to put available HP to getting and keeping it up to speed.

Lighter weights allow the engine RPM to spool up getting to the power band RPMs relatively quickly.
Lighter weights need to be spun faster to be able to push the movable face in. This is essentially the equivalent of running in lower gears. The stiffer a clutch spring is, the higher the RPMs need to be to keep the variator face moving in to overcome the force of the clutch spring. This will tend to keep things down in the power band since as RPM increases beyond the power band, the HP begins dropping making it difficult to force the vaiator face in more to overcome the clutch spring; effectively limiting higher top speed.

Heavier weights Will force the movable face in sooner and cause the belt to begin forcing the pulley faces apart at the clutch end effectively going into a higher gear. Fine for top speed, but acceleration suffers because peak HP is just not there at lower RPMs for quick acceleration..

Load plays a part in that it takes more HP to move more weight. This is where the "low gear/light variator weights" set-up is better for initial acceleration than the "higher gear/heavy variator weights" This is what is needed for heavy loads and for climbing hills since this set-up is best for using the available HP/torque and getting the load moving at all.

It's all trade offs one thing for another. Torque, low end acceleration or Higher top speed at reduced RPM. Pick your spot and tune your system accordingly.

For this next part I am making assumptions, but they seem reasonable to me. Please feel free to correct me and clarify your reasoning if you think I am not correct.

It would seem that using light weights and a softer clutch spring would be about as effective as heavier weights and stiffer clutch spring except that the heavier weight system would engage the clutch sooner and maybe have a higher top speed at a given RPM.

While this is generally true, SF with it's stock rollers accelerates just a few
hundred revs below it's peak power output, and the revs go up slightly
only over 47-48mph.

1 gram less and you're bouncing off the limiter.