Variator and clutch tuning?

[Yager200i]

Ok, I gotta say, the Yager GT 200i is one hell of a bike. It was drizzling rain today, and for some reason, when it's wet outside, the engine just wants to roar, so I let it. I hit 77 mph on stretches where I usually can only get to about 71 or 72. It literally launched itself up to 50 mph so quickly that it was scary. Maybe I should look into fitting this beast with a water-mist system on the intake? Then I'd have that kind of performance all the time.

One thing I don't like is the variator setup. The engine seems to want to shift down to the lowest gear possible (and highest engine RPM possible) for any given speed. This isn't what I'm used to... my old scooter seemed to want to shift UP to the highest gear possible.

And, the clutch doesn't start engaging until just under 4000 RPM. My old scooter started engaging at just over 2500 RPM and was locked by 3000 RPM.

Has anyone tried fitting their variators with heavier roller weights yet? Or putting slightly weaker springs on their clutches so they engage earlier? If so, it'd be much appreciated if you shared your experiences.

[retread]

i have not, new to the yager. being an older post, i'd be very interested to know the outcome of any of these changes if you've made any.

[MotoRandy123]

I was thinking the same thing the clutch engages too high. Aftermarket springs usually engage
even higher. I tried helping the clutch engage sooner by fiddling with the anti rattle dots (sorry
 no picture) a little lube and spread the end of the spring a touch but I  haven't tried it as a
hurricane came by...

I'm not sure about the shifting either. My old scoot seemed to hold one RPM until it came off the
variator. This one moves around a lot. I tried heavier rollers (only 0.5 gm) but haven't tried that
 yet either. Full report soon...

[Yager200i]

Anti-rattle dots? What's that? I know the mechanical basics of the CVT, but have yet to tear into mine to figure out how to lower the engagement RPMs a bit.

I'm also looking for a way to make the CVT go to an even higher gear ratio than it does (or a way to regear the rear end). Not much, just enough to drop the revs by 750-1000 or so at full speed. That'd make it cruise pretty well at highway speeds without redlining, I think.

In another post, you mentioned that the engine makes maximum torque at 6500 RPM, and maximum HP at 8000 RPM. So would it be better to regear so that the engine hits 6500 RPM or 8000 RPM at full speed?

[az_slynch]

I've been wondering about this as well. Hit a new max speed today of 73mph. Just over 100 miles on it since the 600 mile service. Problem is, it hit that speed at ~9250 RPM and it kicked the CEL on briefly. The light went out as soon as I closed the throttle and stayed off when I wound it back up to 72mph. Short run on the highway, roughly three miles. I try it twice weekly as part of breaking in the motor. It gets a 5 mile cool-down at sensible speeds right after that burst each time.

It's kinda annoying, as the bike would hit 66mph at ~8000 RPM prior to service and max out at 71mph at ~8800 RPM. Now, it's tach-ing over into the red zone at 61mph. The bike developed a transmission noise around 500 miles where it would make a sound like a small car horn on takeoff. I followed Yager200i's procedure on bedding a clutch, which nearly eliminated the noise. Now, I occasionally hear a high-pitched squeel momentarily when accelerating once the bike is warmed up. I suspect contaminated clutch shoe linings. I wonder if they're still slipping a bit at high RPM as a result of contamination.

Currently wondering if Dr. Pulley sliders and a HiT clutch would help with the top speed and RPMs. A HiT would at least lock down the clutch shoes at high RPM an prevent slippage. Also thinking of getting a tooth count of the final gears, might be worth upgearing to convert some of the rather brisk acceleration into top speed too.

[MotoRandy123]

 Interesting thought about the clutch. Mine tops out at 60 and that's right at redline.
It always has, I just bought it in October. I thought they were limited to 67 MPH.
If you calculate using 8000 RPM's that's all you can get. That clutch might help both
of us, though I haven't noticed any slipping or heating up of the clutch.
 
 You have to open the final drive to get a tooth count. The Carbed bike has 46/16 46/15
according to the service manual but it's ratios are 2.8 - 1 on the variator and 8.8 in the final
where ours are 2.7 - 0.8 and 8.48 so the cogs might be a little different. I think the Yager
has the torque to pull bigger gears but don't know where to get any. Most of the aftermarket
 ones are for a smaller bike so have a higher ratio.

[az_slynch]

I was looking at the gear issue and found two possible candidates at this time:

Hoca Gears: http://www.partsforscooters.com/Gear_set_gy6?sc=11&category=74091

NCY Gears: http://www.partsforscooters.com/169-186_After-Market_Gear_Set?sc=11&category=74091

Not sure if either set would fit, but they at least give shaft dimensions. I agree, a teardown is in order to determine if either set would work. I'd be happy with a 4-7% upgear and a clutch that locks in at consistent speed/RPM points.

Speaking of the HiT clutch, I believe this is the correct part:

http://www.partsforscooters.com/169-226_HiT_Clutch

I picked my bike up in mid-October and have been using it for daily commuting for the entire month of November since I'm working at a cross-town site. It seems to run fine. Maybe I keep an eye on the gauges too much, but it's always seemed to wind the tach rather high. When I first got it, the bike would rev to almost 7K on takeoff and hold the tachometer at 7K until the CVT was done variating. After bedding the clutch, it revs to ~6250 and holds for a few seconds while the CVT settles in, then climbs to 7K (and beyond). The 6250 launch RPM makes some sense, as that's pretty close to the engines torque peak and the acceleration reflects this.

Once settled at a given speed, the tachometer seems to arbitrarily settle at a random RPM. For example, at a 40mph cruise on a level road, I can get a tachometer reading anywhere between 5750 and 6500; it all depends on how I accelerated to that speed. The tach may be innacurate; I've considered temporarily fitting a Trailtech minitach to validate my primary tach readings. Still, I can't shake the feeling that something is off about the clutch and how it locks up (besides pad contamination).

I'll check it again tonight and see how it behaves. At least there were no ugly noises accompanying the CEL. I figure it's tachometer triggered, which is why it went out as soon as the tach dropped below 9K. Still amazed that Yager200i is getting such huge speed out of his bike. I followed the MotoMan break-in too and have been regularly loading/unloading the motor, while adding in the occasional max-speed sprints in an attempt to help bed everything in and get the motor limbered up. Keeping dino oil in it and changing the oil frequently. I did let my dealer do the 600 mile service to keep them happy and assure them that I wasn't trying to break the bike, but I've handled everything else.

[az_slynch]

Anti-rattle dots? What's that?

I think they're the rubber rings that are fitted to the clutch baseplate that slot into the clutch shoes when they're retracted and keep them from banging against the baseplate. 

[MotoRandy123]

  I had an Aprilia 500 in the past and it would hold one RPM while accelerating (around 7000)
until you came off the variator. The Yager doesn't seem to do that and I agree it seems to
 be at different RPM's at the same speed so is hard to understand what's going on. I know
that if you accelerate to a speed the RPM's will be higher than if you go past that speed and
"back down" into it.

 I tried heavier and lighter rollers just to see. I liked the heavier ones, they calmed the RPM's
down a bit (I could cruise at 5000 RPM's) and when you hit the throttle it would jump to
6500 and motor off but I lost power to climb hills. Stock I could accelerate to 50 MPH up a
local hill and heavier I could only get to 40.

 The lighter ones were just like stock only a tiny bit different in RPM's (200) but the clutch
seemed to engage at a higher RPM and it accelerated at 7200 RPM. I don't know, I've been
trying to get the clutch to engage like it did when stock.

 Those anti rattle dots seem to keep the clutch engage/disengage point very sharp. I tried
relieving the slots a bit as they were tight in there but now it slips before engaging and doesn't
want to disengage at the same point it engaged. It's still tight just not quite as it was. Here's a picture;


 That clutch works great but the price is a bit out of my reach!

 We need to find a gear ratio that works in the Yager. the only gears I have seen are for GY6
or Vespa's. The Vespa's are totally different even some GY6's are different as some mount the
trans stuff on the inside and some on the outside. I don't think they will have a ratio that works
for Yager. Craig Vetter had to have a gear set made for his. I feel the Yager is more powerful
than it's 150cc cousins but they limited it so a new gear would help.

 Actually that's good to know that the CEL light will come on at redline. The bike seems to go
past the line on the Tach so I wondered where it really is.

 On the RPM's to tune for, it's what you like. 6500 is max torque and will give you great fuel
economy but acceleration will be slower. 8000 will give you the best acceleration but poor
fuel mileage. 7000 - 7500 is a good trade off for all around performance. Here's some data
from a guy with a Ruckus, he shows RPM's speeds and mileage, you decide...;
http://fc.greensboroday.org/~epaynter/brcvt

[MotoRandy123]

For break in, I got on and off the throttle a lot during the first 100 miles. It's tough
with a scooter as you cannot go to redline until you come off the variator. I changed
 the oil at 140 miles to straight 30W, it's better for breaking in the top end.

 I've looked at many ways to improve the performance and there aren't many, Kymco
built it pretty good. That being said there are a couple of things that might help. I'd put
some DR Pulley sliders in the Variator. The variator is not fully used but getting the extra
travel out of it is difficult.

 Changing the air tube going into the airbox (and removing the 90 degree elbow inside) will
help it breath. The throttle will feel more connected with no delay for acceleration. The stock tube
has a coupler in the middle that restricts flow.


Advancing the time might give you a bit of power too. You could do the old NTC trick or slot the
pickup in the stator area to move it 5 degree's. A 4 valve head would be nice and there is a new
Kymco with one that should fit....

[az_slynch]

If you're referring to the head from the Prople GT200i or the Downtown 200i, I've been curious if it would fit. It'd be even cooler if the crank and cylinder fit too. a 205cc Yager would zip!

Could always go big too and find a way to import a G. Dink 300i motor over; it's probably a straight bolt-in.

As for timing, I want to say that MRP made an offset woodruff key for the flywheel that would allow you to advance or retard it a few degrees. Can't recall the part number, but I have one on my parts bins, was looking for ways to hack an Elite 80 for more speed and though it might fit.

EDIT: Found the woodruff key info

http://www.martinracingdealer.com/ProductDetail.jsp?LISTID=80000C74-1189796418

[MotoRandy123]

  Well I don't think we get it here but the Joyride in Europe is 171.2cc / 4V / carb / so
maybe the head would fit on the Yager? All of our scoots are 205cc. It's not easy to
tweak the FI so you can't go too far unless you can get info on the injector and find
one that flows more...
 
  The bike feels so strong in the midrange then so slow on top it seams like something
 is holding it back. The injector might be at 100% or the motor might be running out of
 air or maybe that's all she's got. I expected more as some 125's are close in performance...

[MotoRandy123]

Here's a good write up on changing the gears in a Buddy 125;
http://www.modernbuddy.com/forum/viewtopic.php?t=17276

[Zimmerman]

Holy Cow - that write up was amazing !

[MotoRandy123]

 Somewhere along the line I realized my testing was flawed. I one time when I
put the clutch back together the sleeve that goes over the guide dots/slot didn't
bottom out. It was about 1/8" up, there is grease in there causing some "hydo-lock".
This raised the Contra Spring's tension a bit.

 Also the next time I assembled it I noticed it felt notchy once that sleeve was on, so
I moved the dots/slots one position to the left and tried it again. It was much smoother.
The difference is the speed going up hills and overall power. A heavy spring will stay in
a lower gear more so will power up hills (at a higher RPM). It will also "come off the
variator at a higher speed.

 So now I am basically back to the standard setup. I can only do 40 MPH up my test hill
(was doing 50 at one point) and it "comes off the variator" at 55 MPH (was 60). Overall
I like it but wish I could get up that hill faster. I might try shimming the contra. They have
bearings you can add to keep them from binding, that should add a nice shim in there...