CVT tuning

[chaz35]

I ordered some Dr Pulley sliders, hope I am getting the real thing because price was pretty good, not much more than top of the line rollers like Malossi/ Polini, vendor was selling them on ebay and amazon, has good feedback/ reviews so I think probably OK.  Have Dr Pulley 7.5, 7, 6.5gr coming so should be able to dial it in really nice.

With OEM rollers and purple Malossi torque spring, pretty close now.  People 50 2T probably running as well as my Super 9 LC, maybe better.  I keep one scooter at my son-n-laws (50 plus miles away) to ride with him, so can't compare here.  Best way for me to compare is to ride with son-n-law with him on his Super 8 150.

Rode approx 2 hrs last night, was running strong.  Actually, at this point I like my People 50 2T about as well as Super 9 LC, which is saying a lot.  New pipe seems to be running better, maybe needs a break-in.  I don't think it's restricted, or if it's restricted I don't know where restriction is?  It's just a little different than my other Tecnigas pipe, maybe some of the tubing is a little larger diameter, and is a little longer overall.  I may swap pipes between People 50 2T and Super 9 LC to see it makes any difference.

Experience with People 50 CVT makes me want to open up Super 9 CVT and adjust it too, it could definitely be running a little better and needs some attention.

I looked at 2008 Sym HD200 for sale locally yesterday, rode it some, very cool scooter, but at this point I still like 50's better.  I am going about as fast as I want to (especially after dark), a few times need a little more power, but not often.  So far, I am getting my need for speed with 50's and very fun to tweak too.  Nothing to do to bigger scooter, just ride it.  I could be like Harley riders around here, I blew by one a few days ago like he was on a bicycle.  Cheers

[chaz35]

Have some more thoughts on CVT.  I have read CVT are approx 85% efficient.  I assume most of the 15% lost power goes to friction from belt dragging on the variator and clutch pullys.

It seems to me a stronger torque spring will cause more friction/ less HP getting to rear tire.  So, appears want to run the weakest torque spring that gives the performance you are looking for (CVT starts out in low gear and smoothly moves to higher gear as you gain speed with engine running at just below maximum torque).

As HP goes up, CVT will require stronger torque spring to keep belt from slipping on the pullys.  As RPMs goes up, a stronger torque spring will be required to offset the higher force from the rollers spinning at higher speeds, generating more centrifugal force.  Appears you can tune the CVT to run pretty much the same with a stronger torque spring and heavier rollers, compared to weaker torque spring and lighter rollers, but I bet all other parameters the same, the scooter with the lighter rollers and weaker torque spring will be faster.

Cheers

[gosku]

This is very interesting! I bet you did a nice research on the CVT. I'm wondering what Zombie could tell us about this lost friction and what would be the difference between two perfectly aligned sets of torque spring + rollers, but one set being lighter than the other. Hey Z, you around pal? 

I heard that Dr Pulley sliders are more durable, but also their weight doesn't correspond exactly to the weight of rollers, for example if you have 7 gram Dr Pulley sliders and 7 gram rollers they won't work the same way. But it's only what I have heard.

My People 50 definitely needs higher RPM's, it climbs mountains with too low RPMs and on too high of a gear and hardly downshifts if the hill isn't very steep (14% or so). I think I will swap the rollers from 8 to 6 gram first, 7 may give little difference and I doubt that 6 grams will be overkill. I will definitely post in 1,5 week and let you know about my expierences with CVR!

I bought mine with Tecnigas pipe already on it, but I have no clue what model it is. Any clues on how to check that? By looking on pictures, it looks like Tecnigas Next R, but it's not dark or blue, mine looks like carbon fiber or at least a pretty good imitation of it.

[chaz35]

Yes, Z has disappeared for some reason, hope he's OK.

I didn't mention, but I also installed the Malossi torsion controller.  I don't know if it's helping that much, but can't hurt.  I added it to my order when I got the pipe so I could get free shipping.  I like it, will probably order another one for my other scooter.

http://www.scooter-center.com/en/product/M2512827/Torsion+Control+MALOSSI+Minarelli+50+cc

As I understand it, if your CVT is not downshifting when scooter gets slowed down going up a hill, you need a stronger torsion spring.  You want the lightest torsion spring that works properly.  So, if CVT is not downshifting, it's not working properly, may need stiffer torsion spring.

My Super 9 LC has this problem, but I haven't fixed it yet.  After I installed Uni air filter and rejetted the carb to 42 idle jet and 105 main jet, seemed like the CVT worked better on Super 9, but still not perfect.  I think CVT working the same, but engine making better torque so can pull through lower gear better.  I experienced the same effect on People 50 too.

I really like the pod air filters, if you can stand the extra noise.  People 50 was really quite with OEM exhaust, now sounds mean and working hard, not as loud and annoying as chain saw, sounds acceptable to me, don't feel like I need ear plugs, espicially with helmet on.  Plus, in traffic cagers are more likely to notice you are close by which is safer IMO.

I understand the Dr Pulley sliders work a little different from rollers too.  Can't remember if Dr Pulley sliders work like lighter rollers or vise versa.

Another effect I just realized last ride was throttle control is different on scooter with CVT.  Sometimes, when engine is lugged down too much can get a little better performance by backing off the throttle a little, because the carb will work a little better.  But scooter with CVT likes WOT all the time.  I used to race kart with 100cc 2 cycle engine direct drive, no clutch, so coming off slow turns engine was lugged down and liked less throttle better.  I got used to that and now realize scooters don't need you to feather the throttle.

Cheers

[BettinANDlosing]

You got it exactly right with the torque spring, you want the lightest possible otherwise the CVT has to work through extra friction. Those torque control things do actually work, I have the Polini version on my Zuma. I just installed one on a customers vespa that is actually a bearing, and has almost zero friction, pretty cool. One of the most important things you can do to keep the variator shifting right is CLEAN IT!!!!!!! At least once a year, take the variator apart and clean the poop out, I like to use polishing compound to make the boss ultra smooth, and make sure all the belt dust is out of where the boss contacts the movable pulley. Make sure all the ramps are clean of belt gunk, carb cleaner works wonders.

[chaz35]

Thanks for post B&L.  I didn't know how to clean mine, I just put it back the way it was, next time I have it apart I will clean it some.  Brake cleaner is my go to cleaner, so I will go at it with brake cleaner and compressed air.  What about lub, I have seen some CVT grease, what do you think?  I've seen the torque controllers with ball bearings, looks very cool to me, 50's probably don't make enough HP to need that.

Next thing I am looking for is higher gearing.  That's one reason I bought some Dr Pulley sliders, they claim to have a little more top end.  My engine is making good power and just running out of gear.  When I ride it now, I keep it 50mph on the speedo max, it will go 1/2" or more past the final top speed from time to time, but engine sounds like its over revving, so I don't like going there now.  I don't think I am hurting it, just wearing it out faster?

I don't know, but think you can get variators that run the belt a little higher on the pulley for more top gear.  I recall some posts about running the belt high enough to have to worry about getting the belt into the starter gear teeth.  If not too expensive, might try one of those.  I guess you then need a longer belt?

These scoots are really fun to tweak and ride.  I rode mine over 3 hours today, it was a blast.  Cheers

[BettinANDlosing]

Yeah man, the key is to not stay at wot for a long time, over 10k is pushing the stock crank plus air cooling. The "overrange" kits are SICK, i have one for my zuma. Malossi MHR, was about $350 totally worth every buck. I have yet to see one for the kymco engines. It replaces the variator and rear pulley with larger ones, getting low low gear and higher high gear. If you get upgears, your scoot will suffer off the line a bit, if that matters for where you use the bike. I love tuning 2t 50cc's also, you get huge gains relatively. I'm too the point with my zuma where my next stage is gonna be about $600 from Germany and a couple weeks porting the case haha. Maybe my winter project.

[chaz35]

Yes, will be interesting to see how it holds up.

Traffic is pretty fast around here, speed limit 40 to 45mph most roads I ride on, so some cagers driving 50 plus.  If speed limit is over 45mph, I usually stay off that road, except for short runs.  There are a fair number of red lights to wait at, so it gets some rest.  Engine has never acted like it was hot, always idles nice, runs very consistent, starts easy, with 108 main jet it burns lots of gas LOLs.

I suspect it will give good service for long time.  I am thinking positive and ordered some new tires and Malossi variator tonight.  I am hoping Dr Pulley sliders and Malossi variator will give me a little more top end.  Cheers

[chaz35]

Got in Dr Pulley sliders and tried 7.5gr 1st.  I cleaned the variator with brake cleaner and wiped it clean with a rag.  Then, I blew out the inside of CVT casting and cover with compressed air.  At least will be able to see any additional belt dust, next time I open it up.  Put it all back together and took it for a ride.

I want to say, Kymco variator and clutch appear to be well engineered.  Kart clutches are fairly problematic, break easy, come off easy, generally give you trouble, especially if you don't know what you are doing.  The CVT variator and clutch both go on splined shafts which is very good design IMO.  After I get it tuned to perfection, I will use blue loctite to finish it, but up to now only tightened it down with impact, then rode it for hours and hours and no problems.  I was expecting it to come off, but after awhile I realized the splined shaft is doing the business, no problems.

With Malossi purple torque spring and Dr Pulley 7.5gr sliders installed CVT worked very well.  From stop was awesome, acceleration great, top speed a little better, going up hills seems to pull down some gear and pulled up hill on powerband.  I could cruise at less than WOT and stay at max on the speedo just modulating the throttle going to WOT from time to time.

I think with OEM torque spring will take 7 or 6.5gr sliders, but may be making enough HP to slip belt going up a hill or into a strong wind with OEM spring, I don't know.

This scooter is feeling fast, I am very happy with it.  Cheers

[gosku]

Are you going to test other sets of Dr Pulley or are you completely satisfied with the 7.5 gr ?
Heck, I have the purple spring and the torsion controller, can as well go for Dr Pulley instead of rollers... But having in mind what you guys said about the lost power due to friction, maybe it's better to stay on OEM spring, which is softer.

[chaz35]

Probably won't be doing anymore testing until Malossi variator with white spring (I think equivalent to OEM) comes in.  I got the extra Dr Pulley weights so I would have them to use if needed.  Since scooter running so nice, probably just ride it some.  After awhile, I will get my Super 9 back home and work on it's CVT, and now have plenty of parts to get it tuned up nice, too.  Compared to People 50 CVT, Super 9 CVT is lousy now lol's.

I got Dr Pulley because they were not that much more than Malossi/ Polini rollers.  If your's working well, I wouldn't recommend changing it all up just for some small effect.  I haven't tried Dr Pulley sliders with the OEM or white spring, but I am pretty sure going from purple spring to OEM or white spring will change weight of rollers needed, so I may eventually use 7 or 6.5gr sliders.

Also, interesting effect with purple spring and 7.5gr sliders, engine maybe over revs a little from dead stop then settles down some as I gain speed.  I am thinking maybe compromise in design of CVT, maybe not possible to tune out that effect with OEM variator, so will be interesting to see how Malossi variator performs.  I can see getting some more Malossi torque springs to try too, I think there is at least one between the white and purple.  You get it tuned too perfect and you will start to notice changes in how it works day to day depending on the weather/ season of the year lol's.

Cheers

[gosku]

I'm very curious about the Malossi variator. I didn't even know that those are available for our People 50.
Where I live Dr Pulley is nearly 2x more expensive than Malossi / Polini rollers. But that's not a big deal. Anyway, I will stick with Malossi rollers and OEM spring for now, and will do some tests with different weights of rollers. Gonna start on Monday, already called my mechanic. I'd like to be able to mess with CVT by myself in the future, but as for now I've got only a variator blocking tool and a lot of common wrenches, but no impact one. Do you think that impact wrench is a must? And why the loctite?

Haha you nailed it! "Look, there's a mountain! Let's stop now and change the spring in the CVT" 
I've got a similar "thing" going with the carburetor. I adjust the idle screw nearly on a daily basis, especially since the altitude (and maybe humidity) seems to affect it. But it takes just two seconds!

[chaz35]

If you have holding tools, I would use that.  I may eventually get some holding tools for clutch and variator.  Actually, I mainly use impact for disassembly.  I don't think very accurate for assembly, either over or under torque.  I guess if you used it a lot, and had a really nice high quality impact could get pretty good at it.  However, at the kart races, I see them used a lot and causing trouble, like stripping out bolts/ threaded holes, and stuff coming loose.

I use loctite to glue fasterners (nuts/ bolts), keeps them from coming loose.  Don't use red, too strong very hard to disassemble.  I have red, but generally only use blue.

I like to use old fashion beam style torque wrench, I have 2 I have used for 20 plus years and still work great.  The fancy adjustable style needs to be recalibrated after it's used over time and few do that, so not that accurate IMO, simple is always better.

I didn't have impact driver for long time, but eventually got one to save time and my energy.  I worn out the 1st one, batteries wear out over time and won't take a charge anymore.  It's really a great tool to have.  This is link to my latest one, so far I am very happy with it.

http://www.sears.com/craftsman-19.2-volt-impact-driver-kit/p-00931304000P

[chaz35]

I probably don't need Malossi variator, but got it because think it may give me a little more top speed.  Will be interesting to see how it performs, will report on that when I get it and have it installed, may be awhile.

The way my CVT behaves now started me thinking about the fly springs and the angled slots on the torque driver.  I decided early on not to use stronger fly springs for more slip, cause more slip means more heat, faster wear, more problems.  But thought occurred if slip the clutch a little more, rpms will move up and maybe be an adjustment for how soon the CVT moves from lower to higher gear ratio.  Probably nothing here, but I am going to do some thinking about it anyway.

Have also been thinking about angled slots on torque driver.  Not sure how this puppy works, but appears angle varies spring tension depending upon whether engine is accelerating or decelerating.  I noticed Malossi makes one that has 2 sets of slots at different angles so you can use it for tuning, very interesting.

All for now, time to ride my scooter.  Cheers

[BettinANDlosing]

The angles of the torque driver changes how easy the belt can "pull" into higher gear. Think of it this way, if the slots were straight the only thing holding the belt back would be the spring tension, so with more angle the resistance to open the rear pulley is higher. My malossi mhr overrange came with the pulley that has two different angle slots. The steeper angle keeps the rpms up for longer, until the torque shifts the pulley. The main difference from all my looking into it, a lot of stock pulleys have slots that aren't one angle, they get less angle while the pulley travels apart causing that "shift" in some scooters that kills acceleration. The Malossi ramps are straight creating a very constant rpm operation. Took me a long time of thinking it over to fully grasp how important the rear pulley is in a cvt. On a side note the Malossi variator is AWESOME, you will feel a huge difference in smoothness, and acceleration and top speed should be a little better. Mostly your rpm will stay more constant and rev up exactly how you want it to. They take a strange weight size, but you can find the sliders for them. Ps I have a lightly used mhr delta clutch for Kymco engines, just posted in for sale check it out if you guys are interested. Took it out of a used scoot before it sold, would boost acceleration greatly.