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I've been riding my 06 Morphous for the last few days due to my helix having a flat. I continue to be impressed with Yamaha, a completely different feel than the Helix. Extremely stable and tracks like its on rails, however, I've noticed a low speed vibration very similar, but not exactly the same, as my helix.

I know the cause of the vibration with the Helix. It's the clutch shoes which need replacing. A very common issue with the helix. Instead of the shoes engaging smoothly, they slip a bit until you are moving above about 12mph. It's not a big deal, I clean the shoes every once in a while and this fixes the problem for a few days but ultimately I need to replace the shoes.

The Yamaha has a similar issue but unlike the Helix, The vibration is not so much at the initial acceleration but during very slow speeds of 20mph and below, When you are in slow traffic and just lightly feather the throttle, you can feel it, as if you are going too slow for the CVT to react. I mean, it goes just fine It's working but , it seems like it's struggling to keep a slow pace. My brother rode the Morph and he thinks that it's just a byproduct of the CVT but I'm not so sure.
The bike only had 240 miles on it and is super smooth when driving at anything above 20mph.

To explain further, the vibration also happens if I'm traveling at say 40mph and let go of the throttle and slow down to 25 or 30 and then whack the throttle, it vibrates for just a moment (1-2 seconds) to get back up to speed which suggests to me it's the clutch engaging which causes the vibration.

So I'm wondering if any other morphous owners (or anyone with a yamaha scooter)experience the same thing? Sometimes I wonder if I'm just me being overly critical..
 

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I don't have a Morphous, but I think the vibration is probably just final gear ratio combined with a single low displacement cylinder.

Not unlike trying to accelerate in a gear or two to high with a manual transmission equipped car.
 

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hi morph

sry for the bad english..
i have the same problam with my majesty 2007 .
its make me crazy...
i had try to change the cvt to j costa one - it fixed the problam but beacuse i wasntdriving in alow rpm anymore.

does anybody found a real answer to this problam ?
 

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If you have roller weights like other scooter CVTs have, they may be worn. Try taking it apart, blowing the belt dust out and see if that'll help.

Chris
 

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I have also notice a vibration, but it is usually when just idling. Figured it was normal, but now am not so sure. Does the Maj have a noticeable vibration when standing still, or is it just me?"
 

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I changed my roller weights 2000 km ago... it didn't fix the problem.
I think the iding vibration is normal in the majesty beacuse of the single cylinder. My vibration starts in low rpm ( untill 4000 )- when the cvt start to change ratio.

The majw just starts to rattle when I put the maj on the center stand and pull the throttle I see the cvt shaking in the low rpm.
 

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Ok, as long as it is just not me. I am taking it in for service soon, so I will have them take a look at the roller weights, just to make sure.
 

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If you think the roller weights will need to be changed, you might wish to consider putting in Dr. Pulley Sliding weights. Acceleration is smoother and brisker than with the OEM weights.

Chris
 

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Don't think I will have them changed yet since my ride barely has 1100 miles on it, but I will consider Dr Pulleys when I do. Thanks for the suggestion.
 

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I got very curious about the cause of the vibration.

I just finished taking my cvt apart and I found out that when I'm between 3000 -4000 rpm my cvt belt arent tight enough.

The same happend when I'm in higher rpm - go down to 3000 ang go up again. The belt gets lose and all the cvt is shaking....

Thoughts anyone ???

I thought maybe the clutch spring does work good enough or maybe the roller weights are not heavy enough.
 

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mine does it. I kind of feel like the roller weights are moving around like the bottom one drops to the outside and the top one falls to the inside it goes away when I get over 5- 10 miles an hour
 

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Low speed vibration has to do with clutch engagement, not roller weights. This is quite common on CVT systems. Altering your clutch springs to allow for quicker engagement is about the only real solution but keep in mind that you will likely never rid yourself of this. That's the nature of a CVT clutch.

Matt C.
 

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This image is showing the crankshaft portion of the Majesty's engine. I suppose that the Morphous engine is similar.

Check part number 5 :



This part is the balancing shaft. It is driven by the crankshaft. As you can see, this part is not evenly weighted all around it's circumference, it will therefore vibrate quite a lot when it is spinning.

The vibration caused by the balancing shaft is meant to oppose the vibrations caused by the crankshaft and piston.

However, this process is not perfect. I am not physicist enough to fully understand the calculations behind this, but it seems that a balancing shaft can't cancel the vibration of an engine at any RPM. It is tuned to cancel vibrations at the normal operating RPM (on the Majesty, it's around 5000 RPM). This explains why the Majesty is shaky at idle and low rpm.

This method is very efficient nonetheless. My previous scooter, a Yamaha C3 50cc had no balancing shaft. Picture this: cranking the throttle while the small scooter was on it's center-stand on the concrete floor of my garage would cause enough vibration to move the scooter on the floor... It wouldn't stay in place! No such thing happens with the majesty. Small scooters have no balancing shaft because the piston is so small and lightweight that the vibrations remains acceptable when riding.

Without the balancing shaft, the Majesty would probably jump all over the place...
 

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sagi said:
I got very curious about the cause of the vibration.

I just finished taking my cvt apart and I found out that when I'm between 3000 -4000 rpm my cvt belt arent tight enough.

The same happend when I'm in higher rpm - go down to 3000 ang go up again. The belt gets lose and all the cvt is shaking....

Thoughts anyone ???

I thought maybe the clutch spring does work good enough or maybe the roller weights are not heavy enough.
When you checked your belt, the scooter was on it's center-stand and the rear wheel was spinning freely in the air, I suppose. That is why your belt seemed loose: there was no load to pull.

Check this video I made some time ago:
http://www.youtube.com/user/zaran1#p/a/u/0/2efLShaZNJg

The belt shakes a lot. This is normal because it doesn't have much to pull on...
 

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Hi,

Following point of view is just for reference,
Suppose the clutch fully engaged is happened at engine rev e.g., 4000 rpm. There will be three kinds of operations about the clutch engagements as below,

case1):
clutch slippery or initial engaging at engine rev e.g., 3000 to 4000-rpm (ie.less than 4000) → the clutch is slippery on the bell,or rev of bell is less than rev of clutch →no chatter,
case2):
when engine rev is increased and clutch fully engaged at engine rev e.g., 4000 rpm → now the rev of bell is almost same as rev of clutch and if rear wheel drive power created is High enough to overcome the whole resistance then scooter starts to move ahead smoothly and the engine rev is increased from e.g., 4000 continuously to 4000+ rpm →no chatter
case3):
clutch fully engaged at engine rev e.g., 4000 rpm→rev of bell is almost same as rev of clutch but the rear wheel drive power created is Not high enough to overcome the whole resistance then the engine rev will be dropped quickly from e.g., 4000 continuously to 4000- rpm (ie. means less than 4000 or no more fully engaged again)→chatter will be noticed due to repeated phenomena of status1 & status2 until the engine rev is high enough (ie. the rear wheel drive power created becomes high enough again)

So the chatter will be noticed whenever
1) the rear wheel drive power created (when the clutch is fully engaged)
is not strong enough to overcome the whole resistance ( due to the
transmission efficiency becomes poor or clutch is fade)
2) the Resistance becomes higher such as two persons riding,
hill-climbing or big wheel( the rear wheel drive power becomes not
strong enough)
 

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I think it's kool. Rumbling at a light like a Harley!!

Vroom!

Phil
 

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Low speed vibration has to do with clutch engagement, not roller weights. This is quite common on CVT systems. Altering your clutch springs to allow for quicker engagement is about the only real solution but keep in mind that you will likely never rid yourself of this. That's the nature of a CVT clutch.

Matt C.
This is good to know, since I totally rebuilt my CVT. The new Molosi clutch, new rollers (same weight as original as I am only doing town driving), and top drive plate (the old one had cracks in it after 10 thousand K...so, it had to go! Once this was done, it certainly comes off the mark much faster, but on 2 to3000 RPM it loves to 'vibrate'. Not smooth like it is when getting up to 60+ Klm...so thanks for this information...as I thought I might have got it wrong...! Yes, I also installed a new proper belt for it as well and made sure the letters/arrows were facing the right direction. However, when braking on high speed I got a front-end wobble! I think these old tires for 2009 need replacing and balancing! YIKES! Cheers, Vicki
 
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