CVT tuning

[chaz35]

Got pipe on order, so I am researching how to modify CVT to work OK with pipe (Tecnigas Next R).  Not sure if my CVT is stock or not, but works very well with stock muffler, derestricted CDI, and rejetted carb (installed 82 main jet).  I am pretty sure it will be a dog with the new pipe on take off until engine gets enough rpms, then will take off and have better top end.

So, like Z said I probably need lighter rollers.  I also know my other scooter (Super 9) needs some CVT tuning too.  The other day, it was pitiful going up a hill, could bearly make 20mph until I crested the top then it took off.  Doing some reading, I suspect it needs a stronger torque spring for that issue.  Or, maybe have some worn parts?

I know enough about clutches to suspect I don't want stronger fly springs for the clutch, don't want it to slip excessively and generate a lot of heat.  Probably try to stay stock on the fly springs and work around them tuning the rollers and torque spring.  I know the length of the belt is critical, will probably stay with OEM belt.  I am not racing anyone, just want it to work well riding around the neighborhood, be able to go fast enough to stay out of the way.  I am not interested in pulling wheelies or smoking my tires.

Looking around at available parts, I found Scooter Assassins on eBay.  They have a roller kit with various weight rollers so you can do some tuning for a very reasonable price.  Same with the torque spring, there is a kit that has 3 different springs you can try in combination with the different rollers.  Best I can tell, CVT is all about compromise.  You use lighter rollers to stay in lower gear ratio longer, but they can hurt top speed.  To get maximum top speed you may need to sacrifice some low end to get higher top speed with heavier rollers.  Then you need to match the strength of the torque spring to the weight of the rollers.  If the torque spring is too strong, you may need to install heavier rollers for the CVT to properly go from lower ratio to higher ratio, or possibly install softer torque spring.

I realize I know just enough to be dangerous.  I just thought the Scooter Assassins kits looked pretty good for tuning purposes.  After get it dialed in, maybe spend some $'s and get better components, like Dr Pulley sliders, better variator, clutch, etc.  Anyone have experience with Scooter Assassins kits?, any comments welcomed.  Cheers

   

[zombie]

Everything you said is correct as for the tuning of your cvt.

Stay away from Scooter Assassins. They sell China JUNK.

Get a Malossi purple control spring, and a set of Malossi 5 gram rollers. That will match up well w/ any 8k pipe, and last for years w/ a good balance of torque/top end.

You're OEM rollers are 8 gram, and your OEM spring is equal to a Malossi yellow. (S - 9)

It's just that simple.

[gosku]

My mechanic buddy told me that the rollers inside of my stock CVT are 15 x 12, 8,1g. So that confirms what Zombie said. BTW, he took everything apart and measured since I couldn't remove the cover of variator. He struggled with it too  And told me that later I might want to change them for lighter ones. But I don't want to lose top speed because I often ride long distances (100+ miles).

CVT tuning is something I'm interested in too. My derestricted People S 2T is sluggish uphill. On flat ground it has top end 45 mph. I know it could be better. I've got derestricted CDI, vario, a Tecnigas Next R pipe (BTW what do you mean by 8k pipe?). These are the parts which I've already checked, because the previous owner didn't know what was done in his scoot (he just paid money and told some guys to make it run faster  ). I'm mostly interested in making the uphill performance better, since I ride in area with a lot of mountains and there aren't many flat roads here.

All in all, I think I will look up those Malossi parts and give them a try 

[gosku]

Get a Malossi purple control spring, and a set of Malossi 5 gram rollers. That will match up well w/ any 8k pipe, and last for years w/ a good balance of torque/top end.

Looks like my mechanic buddy was wrong! Malossi 15 x 12 rollers don't list Kymco on the list of compatible scooters for this size. 16 x 13 should be the correct ones, Malossi part number is 669823I0.
BTW, it's interesting that OEM rollers are 8 gram, but the Kymco spare parts book states 7,5 gram 

I also found the spring, I think that's the one Z is talking about.



Chaz, Malossi part nr is 298324V0 in case you want to look for it 

Zombie also mentioned "Malossi Black Fly springs for a real kick in the nutz"  in another topic  Are they much stronger than the stock ones? What would be the advantage and disadvantage of using them?

[chaz35]

Hello Z, thanks for reply, probably will do.

I think People 50 2T comes with 8.5gram rollers, Super 9 comes with 7.5gram.  Both are 16x13mm.

Don't know about black springs, but suspect is stiffer spring that slips more, so engine is turning more rpms making more power at take off, so stronger take-off.  If you are looking for fast take-off and/ or hill climbing, may need to go with stiffer springs.  Just be easy until you learn the limits.  If you do a little searching there are threads with pics of burned up clutches, belts, etc.  Faster take-off and more $'s doesn't imply longevity and reliability.

If I was in hilly area, I would probably try lighter rollers and/ or stiffer torque spring, so scooter stays in lower gears longer.  This set-up will sacrifice top speed, so that's the trade-off.

8000k pipe is rpm where pipe makes power.  Stock pipe has peak power lower than 8000k pipe (approx 6500 rpms), racing pipe is higher than 8000k.   You can get pipes that are engineered to make power 10,000 plus rpms, but would be pretty nuts trying to drive in traffic IMO.  An 8000k pipe will be a little harder to tune than stock pipe, a 9000k pipe will make more power still, but be a little harder to tune than 8000k pipe generally.

There are very cool vids of Stage 6 racing scooters on youtube.  There is one where 125cc scooter is racing a bunch of 1100cc motorcycles and runs up front, but I am sure costs lots of $'s, very loud, and touchy to tune.

I am a newbie, have very little experience with scooters or CVT's.  I just know what I have read on web, which can be dangerous LOL's.  I am having great fun with scooters.  It's 30 degrees out today and I am planning to go riding.  Cheers

[gosku]

I'm reading a lot now, I've found a topic with good explanations here:
http://www.apriliaforum.com/forums/showthread.php?8960-Variator-roller-weights-and-contra-spring-mechanics-for-dummies

Thanks for the knowledge that you shared with me/us  I don't care about the take offs since I don't ride in the big traffic, I also don't want to sacrifice top speed (and reliability & longevity!). It's a shame that People S 50 doesn't have the gauge for RPM's, but I'm sure anyway that the reason why my scoot is sluggish uphill is because of too low RPM when going up, you can hear that easily. Funny thing is that when the terrain gets even more elevated, I can hear the RPM's and speed going up. So, it's like on moderate hills it climbs slowly, but on even more extreme ones it actually rides faster  Maybe I should just try rollers 1 gram lighter to see if uphill performance would be better without big sacrifices on flat top end.

Have fun riding today  Here it's cold, 0C. I will definitely look for these videos, must be fun to watch a 125cc ride faster than a big bike.

[zombie]

Both of you guys nailed it.

One gram lighter will help but not as much as two grams lighter. The main focus for hills is the stiffer Purple Malossi control spring for the rear pulleys. It forces the pulleys to stay closed at lower rpm, and gives you a better gear ratio, Just like down shifting.

You will NOT lose any top speed w/ lighter rollers UNLESS they are too light to open the rear pulleys. That is the Only purpose rollers have. To use their weight to counter act the spring in the pulleys.

The heavier the rollers the faster (lower rpm) the pulleys open. The lighter the rollers the longer it holds a lower gear.

I was mostly joking about using Malossi Black springs. They are mainly for drag racing because the bike sits still until approx 7-8 grand, and then it will take off like a rocket (with a proper racing clutch.)

[chaz35]

Yes, scooter drag racing is very cool too.  Have seen good vids of scooter drag racing.  Watched one compilation of a weekend meet and one guy had a monster 2T scooter.  It was killing everybody else, approx 70mph plus in whatever distance they were racing, looked like 1/8th mile to me.  The guys on 4T Chinese Clones were hitting approx 50mph and looked fast on the vid.  Looked like fun, but nobody does it around here to my knowledge.

I was into minibikes before scooters and drag racing minibikes is big too.  But I graduated to scooters and do not miss minibikes.  Still ride in the yard with grandkids, but not on the street anymore, dangerous, illegal...

[gosku]

I was mostly joking about using Malossi Black springs. They are mainly for drag racing because the bike sits still until approx 7-8 grand, and then it will take off like a rocket (with a proper racing clutch.)

Haha good that you mention it now 

I'm not an expert but I think that 50mph on a Chinese 4T is a very nice speed. But I'm sure that 2T will always be faster, plus they are easier to work on and mod. 70mph is an enormous speed for such a little thing. I once heard that Yamaha Aerox is one of the fastest 50cc scooters that you can easily derestrict and modify to get speeds around 60mph.

OK so now I'm wondering whether to just get 6 gram rollers and stick with the stock spring, or go with the setting you proposed, that is the purple control spring and 5 gram rollers. Did you try both of these settings? The purple spring is stiffer than the stock one, and the 5 gram rollers are much lighter than the stock ones. Will these be able to open the rear pulleys for the top speed?

[zombie]

It's a good combo for a 2t w/ an aftermarket pipe, ans carb work (re-jetting). If the bike is otherwise stock 6 gram, and the OEM spring is just fine. Better take off is the advantage along w/ better recovery in turns.

I've messed with a dozen springs (fly, and contra) as well as every combo of rollers you can imagine to run with them.

My ZX currently has 3 gram Polini rollers/Malossi red control/Malossi torsion controller/Stage 6 MK II clutch, and Malossi red fly springs. It's set up on an 82cc Polini Corsa/44mm stroked Doi clone engine w/ a 24mm OKO flatslide, and a Scorpion 9k pipe. Take of rpm is approx. 9k.

The bike red lines at 14k rpm thanks to an HPI programmable CDI so 0-60 is around 4 seconds even with taller rear gears.

I've been tuning case porting that bike for years, and I know it is the best it can be the way it sits today.

If anyone wants it, I'll trade for a bottle of Whiskey, and a pack of rolling papers.

[gosku]

I guess I will have to experiment and see what works for me... I want to replace the belt & rollers anyway. I will start with 6 gram Malossi rollers and stock spring.

Nice! I admire the amount of time & patience you invested in testing all the settings. It must feel sweet when you know that you've tried every setting out there and actually found the sweet spot!

So... do you ship internationally? 

EDIT: Wait, what? 0-60 MPH in 4 seconds? 

[chaz35]

dude Warsaw, Poland!, that's cool, I am in Dallas, TX...it's a small world indeed.  Cheers

[zombie]

So... do you ship internationally? 

EDIT: Wait, what? 0-60 MPH in 4 seconds? 
« Last Edit: Today at 07:48:36 AM by gosku »

Yes, and Yes. 82 mph top speed. Verified by a local cop, and his radar gun at Carabelle airfield, April 2014.
Since then I have removed the primary gears, kept the secondaries for a final gear ratio of 8.1::1, and ridden it exactly 32 miles.

Here's one of the threads on the bike. There's also a build thread on here somewhere...

http://www.kymcoforum.com/index.php?topic=11422.15

Build thread (incomplete)

http://www.kymcoforum.com/index.php?topic=6494.msg67418#msg67418

[gosku]

Niiice! The part that got me laughing the most when was you stated all the details of the build of ZX and Vivo replied: "Lol! I thought you were listing your store's inventory...!" 

It's all like unbelievable to me... You're a boss man! Wouldn't you like to work for NASA?  First spacescooter in history, made by Z 

[zombie]

NASA wouldn't let me bring weed to work. I had to turn them down...

I went nuts on that bike. It was fun, and worth every penny but I moved on to other things. Now I'm building a solar powered, vacuum assisted, fractional, concentric fuel ethanol column. It took longer to figure out what it is called than it took to design. It's about half built (prototype)
I have that, and a new design in Hydrofoil sport boats that are taking up my time. I had to put up a garage for building that prototype.

On top of that, and work every day... I've started classes in Organic Chemistry, and Pharmacology.

My goal is to be the first guy to sail a wind surfer to Mars, open a bar selling my own hootch, and make super drugs out of moon rock.
NASA can kiss my butt! I got this!