Stage 6 pro replica on kymco super 8

[sai]

It's running 45mph at 8500-9000rpm
But even at 11000rpm, it maxed out at 50+ mph

This is with 8gram rollers. Should I go even lower?

[190mech]

Yeah,I always go lighter till the belt doesnt get full travel,then back up till it does..Are you using a marker to check travel?

[Lucass2T]

I think your setup has a similar powerband location (rpm wise) as my setup.
Max power (powerband peak) is at around 10k and max rpm (@topspeed) at around 11500. I use 4.4 gram rollers, yellow malossi contra and a straight splined torquedriver. That state of tune let's me sit around 10k rpms during acceleration. At around 60mph it starts going into overrev until 11500 @ 70mph.

Myself i always tune on feeling in stead of looking at the belt travel first. When starting off with wayy to heavy rollers you can feel where the powerband starts, peaks and declines (because tuned rpm is below powerband and when speed increases at one moment you'll start hitting the powerband). When you determined where your powerband rpm wise is you can start finding the roller weights that let you sit dead in the middle of your powerband peak during acceleration, thus where you'll have maximum power.

When you've did that and your top speed is still too low you'll need to upgear.

[sai]

Sept 12, 2015 4:46:32 GMT -5 190mech said:

Yeah,I always go lighter till the belt doesnt get full travel,then back up till it does..Are you using a marker to check travel?

Yes, I am.

Yesterday with 8grams I still got about a few Millimeter of marker left but I was going 1 block trips. I haven't checked it after I came home from 40mile trip.

What I do notice is that during acceleration, it sits and jumps up to 8000rpm VERY quickly and it scared me. It felt very revvy.

Is this ok?



PS: I also noticed that it's VERY hard to get over 9700rpm. I do get to 10.000 and over but it's tough and I have to WOT.

[sai]

Sept 12, 2015 7:08:15 GMT -5 Lucass2T said:

I think your setup has a similar powerband location (rpm wise) as my setup.
Max power (powerband peak) is at around 10k and max rpm (@topspeed) at around 11500. I use 4.4 gram rollers, yellow malossi contra and a straight splined torquedriver. That state of tune let's me sit around 10k rpms during acceleration. At around 60mph it starts going into overrev until 11500 @ 70mph.

Myself i always tune on feeling in stead of looking at the belt travel first. When starting off with wayy to heavy rollers you can feel where the powerband starts, peaks and declines (because tuned rpm is below powerband and when speed increases at one moment you'll start hitting the powerband). When you determined where your powerband rpm wise is you can start finding the roller weights that let you sit dead in the middle of your powerband peak during acceleration, thus where you'll have maximum power.

When you've did that and your top speed is still too low you'll need to upgear.

Hmmm... this is a detailed CVT tuning that I'm not used to. even at around 10.000rpm-11.000 rpm, it peaks out at 50mph.
I'm going to try going into the 6gram this time from 8gram and see what it does.

So it's ok it sits at say 8000-9000rpm while the speed picks up? Is this what it's supposed to be?
I always thought that as RPM increases, the speed should increase with it?

[moofus02]

If the 6 are to light you can mix 8 and 6 staggered for the equivalent of 7's

[Lucass2T]

I tried to visualize how a revs and speed are compared with a cvt engine.
The picture below shows how my engine behaves. Let me explain:



As you can see from the black line, the engine is revving up but the scoot is not yet moving until it reaches 9000rpm, thats when the clutch starts engaging.

Then at around 10mph (i think in real life its more, but haven't exactly checked) the clutch is fully engaged and the cvt takes over. Then rpm's rise a little bit more and up until about 60mph the engine keeps on and around 10k rpm.

Then at around 60mph it starts running out of gears (the cvt is at its maximum reach) and rpms start rising and a little bit later the engine starts going into overrev. Overrev is the area where there is not much power is made and only heat is generated (stay away from there!).

In this film (@5:00) you can hear what i just drew above. Clutch area, cvt area and the moment when rpms starts climbing and the engine is going into overrev.

[190mech]

Thanks for the vid Lucass!That shows how a well tuned 2T should run and sound..

[Lucass2T]

In the vid (from 5:00) you can clearly hear my clutch springs are too weak. But i did that on puprose to make slow take-offs possible. To minimize drawing attention when i encounter cops and i have (for some reason) to accelerate next to them. Just keepings revs low.

[sai]

Sept 13, 2015 3:16:48 GMT -5 Lucass2T said:

In the vid (from 5:00) you can clearly hear my clutch springs are too weak. But i did that on puprose to make slow take-offs possible. To minimize drawing attention when i encounter cops and i have (for some reason) to accelerate next to them. Just keepings revs low.

Thank you so much for sharing the vid . I'm trying to know when my engine overevs , but I don't know what to look for .

Is it when it sounds like it spins super fast but doesn't feel like there's a belt attached to the CVT and it's just spinning on its own?

[iwiketuddlz]

Thanks for that lucas.!!! I have mine set to grab around. 6k as well so I don't draw attention it's effects my takeoff from a dead stop but if I'm rolling say 10mph I can kick it and off I go...! woot..!

[Lucass2T]

Sept 13, 2015 9:41:07 GMT -5 sai said:

Thank you so much for sharing the vid . I'm trying to know when my engine overevs , but I don't know what to look for .

Is it when it sounds like it spins super fast but doesn't feel like there's a belt attached to the CVT and it's just spinning on its own?

Yeah thats the hard part, it's mostly on feeling and describing a feeling is not easy.
Im gonna try to explain, maybe a bit difficult to understand. Maybe someone can back it up if needed.

Overrevs occur mostly somewhere close to topspeed, where (with a cvt engine) you can clearly hear the engine starting to climb in revs again. In the movie i posted at exactly 5:25 you can hear the revs starting to climg again after some time staying at a flat line.

Depending on gearing, it's near topspeed. If your engine is geared very light, topspeed is low and the engine can overrev a lot. When geared heavy, topspeed is high and overrevs are little. 

When the cvt is tuned correct, the point where revs starts to climb again is the point where the engine is starting to go into overrev. Myself i don't go there that much because thats beyond 60mph. I don't do 60 that ocasionally. But if your scoot is geared more lightly, and you have the same amount of power is i have, overrev will occur at lower speeds and reaches (rpms wise) furter. With my scoot, overrevs are quite limited because the engine doesn't have the power to take it anywhere far beyond peak power (powerband peak) due to air resistance.

[sai]

I think I get it. I have felt this before when the RPM goes beyond 11k . But even then the top speed remains at around 50mph. This is with either a 9gr or 8gr roller. The 8gr of course gave me a tougher time to hit the higher RPM and top speed.

I do have a 6gr and 7gr roller I can try to put in if I have to.

[Lucass2T]

First you need to determine where your powerband peak is. Use a rpm counter to point out the rpm where you make most power. So put the heaviest wwights in and do some testruns. It's not that hard only you have to feel where your engine pulls the hardest and quickly look at your rpm gauge.

Then tune your cvt to that rpm. Then you're done actually. 

When you're making crazy rpm at around top speed you will either have to put in taller gears, go into overrev a lot and risk overheating and/or seizing or don't go all out all the time.

[sai]

From what I have noticed it's usually between 8300-10.000+ rpm

After 11.000-13.000 rpm it feels like it revs quite a bit more and I'm not getting faster than 53mph