variator tuning

[aznatama]

I figure this goes in the performance since I got the engine running fine now. (I think).

So I went from 5g weights and a 1500 tq spring to 4g weights.

Wow, acceleration is much better off the line and up hills, BUT... I'm not over-revving. I'll hit 10k at less than 1/2 throttle, and that causes problems since it ends up running lean and with too little oil. I tried to maintain 40mph, but the revs were too high and I had another soft seize. :-(

So obviously I need to either go up in weight, or down in tq spring.

What do you guys suggest? I'm thinking a 4.5g or 4.75g, or changing the tq spring to a 1000rpm one.

I know that a stiffer tqspring allows the variator to "downshift" sooner for hills, but at what point would it be too much? w/ the 5g/1500rpm setup, I was holding at about 6700 when first accelerating, with revs climbing slowly as I accelerated (depending on throttle), I'd like this to be about 7500. Also, going up a small onramp from a dear stop, I would be stuck at about 6700 until I got to the top, and I'd like to increase this as well since my acceleration stagnates at too low a speed.

thanks!

[90GTVert]

Try a staggering the 4 and 5g weights for 4.5g first and see what that's like, since it's the easiest swap. If you have other contra springs around, you could try 4g and a 1000RPM and see what that's like. I don't usually mess with the contra too much. I have played with them a good bit in the past, but it seems that as long as I have the right balance of weight vs spring stiffness I can do OK without fussing over the contra. I usually stick to one of the softest contra springs that I can make work with the weights I have. Really stiff springs mostly seem to cause me more work when I'm tuning or servicing anything else in the CVT.

About the only other time you'll find me obsessing over a contra spring is when I'm losing revs once the CVT is hot. Even then, I'm usually just seeing if any of the same spring rate spares I have may react less to heat.

[aznatama]

I have the S6 tuning set from 3~4.5, so I can swap to all 4.5g weight no problem. The only extra work would be the swapping of the casings for the weights. I know 5 is too heavy w/ the 1500 spring, and 4g is too light, but I like the cruising rpms w/ the 5g. Hoping for a compromise somewhere between these weights.

I'll try with heavier weights and then report back.

[aznatama]

Does anyone know how to solve this problem?

When I gun the throttle, the revs will surge and I'll get a quick burst of acceleration, but then the engine will come back down and acceleration will slow significantly. ?? weight s too heavy? contra spring too light?

[rupert]

I *think* you are fighting the ramp in your take-up pulley. If you look at the pinned slot in the center of the moving pulley half you can see that the incline is harder for the second 1/2 of it's travel....... so the first bit is easy (your rev surge), then it get's into the harder bit and bogs. I'd try a lighter rear spring (if you have one) and tune from there.

You guys insist on doing variator tuning a55 about face, and this is the result.

[aznatama]

Not sure how a lighter spring would solve this? Wouldn't this make it open sooner, thus increasing load at a lower rpm? I want it to stay closed as long as possible, and NOT open at all until I hit a certain rpm. Trying to get it to stay at a stable RPM while accelerating. Right now, it seems like speed is completely RPM dependent, and scooter will not accelerate while staying at a certain RPM at all.

[rupert]

The first thing you change in the transmission set-up is the rear spring (take-up), but only when there is evidence of belt slippage (black marks on your variator), most 70cc set-ups can get away with the stock spring (#750), or at most a #1000 spring. Next is the clutch...... you don't want the clutch engaging before you hit your power band....... now you can juggle your variator weights, the ideal being no movement of your variator before the clutch is engaged. This will give you your maximum acceleration, but kick the $hit out of your fuel mileage.

Typically here I run: a #1000 spring, the clutch doesn't engage before 6000rpm, and 3.5g weight(s). My "power" hits @ 8500, no matter where I am, or what I am doing, the front wheel lifts @8500.

[aznatama]

What would you suggest to get the clutch to engage earlier, but the variator not move until it gets more into the powerband? I need a balance between daily/late-night riding and performance. It seems to be very difficult to obtain.

Is there a way to do this without changing clutch springs? I have the Naraku clutch w/ red springs, and RacingPlanet has already told me that red is usually the stiffest (even though the springs in the clutch are unmarked). I am suspicious that RP is just blowing BS-ing though, but the engagement right now is acceptable (engaging at about 3-4k? tach is soooo slow, I can never tell). I don't want to be launching off the line all the time though.

Am I asking too much to just have my variator stay stable AND accelerate at that stable rpm? I thought that's what a CVT is supposed to do, yet I can't get mine to do that. It'll only accelerate when the RPM is increasing, even though I can back off the throttle and RPM after I get to a certain speed.

[moofus02]

A strait grove rear pulley like the 08 and up zuma is like that and rpms stay consistent till I run out of belt travel my Eton shifts like you describe

[rupert]

You will have to change (or modify) the ramp on the take-up pulley..... Brent did a write-up on that in the builds section........... it's this ramp, or ramp angle, that is not giving you the "stable" acceleration you are looking for. Looking at what you have now you get stable acceleration until the ramp steepens, then it becomes laggy. In my case the transition here happens right at the threshold of the power band, so it isn't noticeable. Aftermarket take-up pulley halves come with multiple ramp selections for you to tailor your acceleration.

[oldgeek]

You and I are basically in the same place with the CVT. If you still have the 1500 contra spring installed, you should go to a lighter one.

I also have a 1500 contra, and need 6 gram weights to keep it from overreving. I plan to put the 1000 contra back in as it was much better and easier to tune. I have learned just as you have that you must be near WOT at your cruzing speed or you are just asking for a soft sieze.(thanks 109mech and others for finally driving that home for me!)

I think the only solution for earlier engagement of the clutch is softer springs.

I am thinking my setup will end up with 1000 contra, 2000 clutch springs, and 4.5 gram sliders.
Which should give me decent takeoff, decent acceleration, and top speed around 50 @ around 10,000 RPM

Just keep riding,
Scott

[aznatama]

:-( I thought these were supposed to be simple... it seems so much more compicated than a regular manual transmission. LOL

As for WOT at cruise, that would be impossible unless I drag the brakes. WOT would take me past 55mph and over 10k RPM... the only way I can stay at 45 is 1/3-1/2 throttle, which has resulted in soft seizes. I'm now alternating between 35-40 to avoid soft seizing, and also put some oil in my tank.

As for going down in contra spring rate, I have a 1500 spring in there now, and 5g weights again. I get the surging w/ the heavier weights, and just high rev cruising w/ lighter weights. Not sure about the issue here. If I go down in weight and down in contra rate, wouldn't I have the same problem? I though higher contra spring rate would make it "downshift" more quickly on hills?

[snakeplissken]

My understanding is 3 to 5 gram rollers you use a the red spring ( stiffest) 5 to 7 gram rollers you use the yellow spring and use the blue spring for anything heavier than 7 gram rollers. The setup isn't rocket science but alot of it depends on the weight of the rider and what your looking for. How far do you ride when in your so called cruising speed? if it is a couple of miles then setup with heavy rollers and light spring you can even use the stock spring it seems very light.

[oldgeek]

Apr 4, 2013 18:30:59 GMT -5 aznatama said:

:-( I thought these were supposed to be simple... it seems so much more compicated than a regular manual transmission. LOL

As for WOT at cruise, that would be impossible unless I drag the brakes. WOT would take me past 55mph and over 10k RPM... the only way I can stay at 45 is 1/3-1/2 throttle, which has resulted in soft seizes. I'm now alternating between 35-40 to avoid soft seizing, and also put some oil in my tank.

As for going down in contra spring rate, I have a 1500 spring in there now, and 5g weights again. I get the surging w/ the heavier weights, and just high rev cruising w/ lighter weights. Not sure about the issue here. If I go down in weight and down in contra rate, wouldn't I have the same problem? I though higher contra spring rate would make it "downshift" more quickly on hills?

I don't have enough experience to help much, I was just telling you my own experiences.

I dont know your whole setup, but it sounds like you need a larger main jet? Or smaller? Be careful adding oil to your gas tank, that just leans out your mix more according to what I have been reading.


Just keep riding,
Scott

[usmcdoc]

I run a 1.5K contra spring with 5 gram KOSO sliders. Take off is jet like up to 30...then it'shifts' and makes its way up to 50 mph quite fast...and runs at 9,000 rpm at 50 mph...