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Honda Vario 125 Takeoff shudder


SlowRida
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I am often very gentle on the throttle, but i do want better take off rather than just slipping the clutch and lugging the engine on uphills so i changed some parts of the cvt, particularly the roller weights (15-14 grams). Now the whole scoot shudders when feathering the throttle at 8-11 kph. I switched back to stock configuration and the shudder is gone, now it just slips way too much at takeoff.

Currently i have the ncy variator w/ 14 grams as well as ncy clutch with 800rpm clutch spring and contra spring, the shudder is there but it is not very noticeable, but the gearing feels too high for hills so i intend to either increase the contra spring rate or decrease variator weight.

I had the feeling that the shudder is because the engine is quite torquey at low rpms, and that same torque is wasted on clutch slip hence the reason why I'm changing parts 

Any ideas how i can switch to lower variator weights without having shudders?

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Many tens of thousands of riders do just fine w/ stock transmission

in the  Click/Vario

that top Honda engineers specified...

Shocking that you attempt to re-engineer

disappoints.?

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#1 Clutch shudder is normally caused by dust in the clutch. caused by being ridden too cautiously. But since you have had the whole thing apart the dust may have been cleaned out.

 

#2 You have changed too many things at once. So which bits made what difference we don't know. We don't have Vario here? So I will assume the same as a Click 125 which uses the old PCX 125 engine.

Stock weights are 15g or 17g on the newer ESP set up. Conventional thinking says 85-90% for a bit more get up and go. So 12g or 13g should do the trick. With stock spring. Engine produces max torque at 5000rpm so for uphill work the engine should be kept at that. 

 

#3 800 rpm counter spring? I have never really figures out what means. 800 rpm clutch springs OK.  That should mean that the clutch engages at 800 rpm which would be about 800x2.85=2280 rpm which seems a bit low to me. My Zoomer (110) stall, as I bought it, was 3150. So 1000rpm higher than yours. Now it is 5300 which is better for uphill 2-up. ( max torgue at 6500). I am using Dr. Pulley variator and 11g weights all else is stock.

.

#4 I don't have any experience with NYC. It has a slightly smaller included angle at 28 degrees vs 30. but is the same diameter as stock . Or used to be. Whether it is machined, like Dr.Pulley/J.Costa to allow the weights to be more recessed at rest, lower gearing, I do not know. Did NYC come with a longer bushing than stock or shorter? Use the longest one.

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2 minutes ago, papa al said:

Shocking that you attempt to re-engineer

disappoints.?

A few years ago my brother-in-law bought a new 125cc motorbike and decided to start replacing parts in an attempt to make it faster, after several months the thing was junk, hard to start, always needing adjustments, not a smooth ride anymore.  Always replacing parts in an attempt to get it back to normal. Somethings are best left to the pros.

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3 hours ago, papa al said:

Many tens of thousands of riders do just fine w/ stock transmission

in the  Click/Vario

that top Honda engineers specified...

Shocking that you attempt to re-engineer

disappoints.?

I do know what the problem is, I'm just trying to find if people had actually solved the issue of the trans allowing for more torque than what the clutch could effectively transfer at low speed. Basically matching the engine speed at low speed to the capacity of the clutch by finding the right combinations, it'll eventually show itself, but asking at a forum is much easier lol.

 

Also stock  is mostly fine, especially for relatively flat and open areas. But for my use case, which necessitates frequent stops and a sudden steep ascents and long stretches with shallow gradients, I'd prefer a more prompt 0-50 rather than the stretched out acceleration of the stock config, as well as a bit more revs to hold the speed steady rather than lugging it and needing to pump the throttle often. The stock config would definitely be ok, I'm just trying to find my ideal configuration that doesn't necessitate constant 50% throttle. Top speed is also not too important for me, others tinker with the cvt to eke out more top speed, bit I'd be fine if it tops out at 90 if it could reach it sooner. 80 is the legal limit lol.

 

I do realize that a more powerful motorcycle or a manual transmission would solve my problems, but yeah it is what it is

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3 hours ago, VocalNeal said:

#1 Clutch shudder is normally caused by dust in the clutch. caused by being ridden too cautiously. But since you have had the whole thing apart the dust may have been cleaned out.

 

#2 You have changed too many things at once. So which bits made what difference we don't know. We don't have Vario here? So I will assume the same as a Click 125 which uses the old PCX 125 engine.

Stock weights are 15g or 17g on the newer ESP set up. Conventional thinking says 85-90% for a bit more get up and go. So 12g or 13g should do the trick. With stock spring. Engine produces max torque at 5000rpm so for uphill work the engine should be kept at that. 

 

#3 800 rpm counter spring? I have never really figures out what means. 800 rpm clutch springs OK.  That should mean that the clutch engages at 800 rpm which would be about 800x2.85=2280 rpm which seems a bit low to me. My Zoomer (110) stall, as I bought it, was 3150. So 1000rpm higher than yours. Now it is 5300 which is better for uphill 2-up. ( max torgue at 6500). I am using Dr. Pulley variator and 11g weights all else is stock.

.

#4 I don't have any experience with NYC. It has a slightly smaller included angle at 28 degrees vs 30. but is the same diameter as stock . Or used to be. Whether it is machined, like Dr.Pulley/J.Costa to allow the weights to be more recessed at rest, lower gearing, I do not know. Did NYC come with a longer bushing than stock or shorter? Use the longest one.

Thanks for the info, but yeah, the shudders started as soon as i dropped roller weights and kept all others stock. The current setup works fine but the roller weights actually ended up being too heavy (probably because of the pulley), almost like having 16 or 17 grams on the stock pulley (15 is stock)

 

I appreciate it though, i might just end up going the easy way and slapping higher rated clutch springs so it fully engages at speeds that no longer slips. 

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3 hours ago, bbko said:

A few years ago my brother-in-law bought a new 125cc motorbike and decided to start replacing parts in an attempt to make it faster, after several months the thing was junk, hard to start, always needing adjustments, not a smooth ride anymore.  Always replacing parts in an attempt to get it back to normal. Somethings are best left to the pros.

Made engine adjustments probably? I wouldn't go that far, unless i actually had an entire service center's worth of tools and equipment with me, as well as a second bike

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On 12/19/2021 at 1:00 PM, papa al said:

Maybe use 1/2 heavier and 1/2 lighter weights.?

I might try that eventually, but yeah, basically I'm trying to get the engine to rev a bit more at a given speed so it doesn't lug itself. Just that the clutch can't handle it at lower speeds lol

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3 hours ago, papa al said:

Many tens of thousands of riders do just fine w/ stock transmission

in the  Click/Vario

that top Honda engineers specified...

Shocking that you attempt to re-engineer

disappoints.?

In all my bikes I have NEVER had one that was stock.

Part of the attraction is making the bike your own - get it to do what YOU want, not some bean counter in wherever it is designed.

Stock tries to be a bike for all things - which does not exist.

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1 hour ago, SlowRida said:

i might just end up going the easy way and slapping higher rated clutch springs so it fully engages at speeds that no longer slips. 

Or buy some grippier clutch shoes. But unless you have modified the engine to produce more power I think Honda installed ones that will cope?

 

Try riding down a hill with no throttle and see at what speed the clutch disengages. Mine drops out at 15kph. This is not scientific but will give you some idea.

 

I made a mistake, I read the wrong website,  your max engine torque is at 6500  rpm same as mine. https://bikez.com/motorcycles/honda_click_125i_2017.php My quoted 5000 is for the 150.

 

If you don't want to lug the engine going uphill then the weights need to be light enough to allow at or near 6500. https://www.lazada.co.th/products/digital-tach-hour-meter-tachometer-with-sensor-rl-ts002-motorcycle-engine-resettable-maintenace-alert-rpm-counter-i2480960063-s8740405511.html?spm=a2o4m.searchlist.list.5.5c254d62a32vAk&search=1&freeshipping=1

 

 

Edited by VocalNeal
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I had the same problem with PCX 125 2011 and Yamaha FreeGo 125 2020.

 

The simplest and most effective is a more hard torque driver spring and changing the angle of the variator - 13° for a movable half-pulley and 12.5° for a fixed. The cost of work in CNX mechanical workshop is 200 THB and 15 minutes.

Roller weights  left as standard, or 1.0 - 1.5 grams lighter, for different conditions.

 

No problem anymore ;)

 

You can replace the clutch pads more larger - in the photo on the right the standard clutch.
Honda PCX 125 - 150, Honda Vario (Click) 125 - 150, Yamaha N-Max, Yamaha FreeGo, etc have same clutch.

 

All recommendations are only based on my experience and common sense ;-))))

 

 

var 1 1.jpg

var 2 1.jpg

vario clutch 1.jpg

vario clutch 2.jpg

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With modified pulleys, you already have higher RPM than with stock  pulleys.

 

When I move to the mountains I lighten the rollers weights by 1 gram, which increases the RPM by 500 - 550 +/-  at the same speed.

 

Under normal conditions, acceleration with modified pulleys and standard rollers weights is enough for me.

 

Don't forget about more hard torque driver spring and also about the reinforced clutch pads.

 

There is no limit to perfection ))

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Takeoff shudder can occurs due to belt slippage on the variator pulleys, not only clutch slippage and torque driver belt slippage. 

 

This can be seen by the scuffs on the pulleys.

 

Modified pulleys  13° for a movable half-pulley and 12.5° for a fixed remove this problem.

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200 THB and 15 minutes for both half-pulleys.

 

Works like the Malossi kit, but the cost is different ...

 

And there are no crazy customs and delivery payments ;)

 

Angle of the half-pulleys is the same as Malossi.

 

 

vario clutch 3.jpg

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7 hours ago, papa al said:

U do 

shipping too?

 I made this modification for all my bikes and for friends who live near me. 

 

If you don't have access to a lathe, I can buy new original pulleys, modify them and send them by TH EMS.

 

Send me PM with the  bike model and the year production and I will reply the final cost.

 

Overcharge 60 THB - the cost of a cup of coffee while I'm waiting for the turner to complete the work 😉

 

It's not difficult for me, let's consider this a hobby, not a business :))

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30 minutes ago, U CNX said:

 I made this modification for all my bikes and for friends who live near me. 

 

If you don't have access to a lathe, I can buy new original pulleys, modify them and send them by TH EMS.

 

Send me PM with the  bike model and the year production and I will reply the final cost.

 

Overcharge 60 THB - the cost of a cup of coffee while I'm waiting for the turner to complete the work 😉

 

It's not difficult for me, let's consider this a hobby, not a business :))

Excellent.

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On 12/21/2021 at 4:51 PM, U CNX said:

Angle of the half-pulleys is the same as Malossi.

So Malossi is 13° but for which scooter.? I will add it to my list

They sometimes differ from model to model. PCX is different to SYM 300. Malossi outer for vespa 150 is 14° while inner is 15° 

 

 

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59 minutes ago, VocalNeal said:

So Malossi is 13° but for which scooter.?

Malossi vario for N-Max 150 have angle - 13° for a movable half-pulley and 12.5° for a fixed.

 

OK for Yamaha Freego and many Yamaha's model toо.

 

Big Honda CNX guys use the same angles for the PCX 150.

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4 hours ago, VocalNeal said:

So Malossi is 13° but for which scooter.? I will add it to my list

They sometimes differ from model to model. PCX is different to SYM 300. Malossi outer for vespa 150 is 14° while inner is 15°

Does one degree make that much difference ? 13 - 14 is not much in a pulley 25cm in diameter

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On a PCX the pulley diameter is 117mm stock. I did draw one full size in section once but forget the actual distance. Maybe 1-5mm-ish. This of course in the above case will be machined off the base and in theory should be added back by using a longer bushing. But I'm thinking for 200 baht they don't. 

Belt will still be 2x15° so will wear down to 13 and 12.5 after about 400-ish km. The rear pulleys still being 15°. 

It is a  one size fits all,  local solution. But if the rider thinks it "feels" better after, then so be it.  It is after all cheaper than a new belt or a set of weights.

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Thanks. F-ed up with the 25cm - was thinking of my Forza not PCX,

On snowmobiles back home all that was changed, if memory serves, is the spring rate and the weights in the clutch itself. Never heard of pulley halves being modified.

But was a long time ago since I messed with that stuff.

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papa ordered a new pulley set w/

the angles suggested by U,

... prolly.

The 9-y/o Nouvo125 is like ...

 the doggiest.

Gets passed by Snoopys ...

ridden 2-up.

///////

Will do some before/after

acceleration trials.

////////

Belt is original,

& 6-y/o tires are checked.

Will delta those too.

>>>>. Safety for hauling the birds around.

 

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I think OP you got really expert advice here, and here is what I know of CVT; from what you say your lighter rollers make the engine rev higher before the pulleys are pushed together...., so , the clutch only engages a bit later but with higher rpm...

 

In this case I reckon the clutch shoes and clutch assembly can't smoothly engage, can't take the speed and force, due to this high rpm, hence the shudder. As mentioned bigger shoes might help, another option is to use weaker torque spring, this spring also prevents clutch engaging earlier - that's the contra force on rare drive pulleys, hence the name contra spring.

 

This weaker spring (no idea how the rating works, 800rpm, 1000rpm etc., I'm sure you figure it out) may help clutch engaging at lower rpm, but still give you more torque at mid-range on the hills...! maybe...

 

CVT is in a fine balance, trying to improve one thing causes issues other places - I use lighter rollers and have more acceleration now, but lost some top speed..., as expected. I'm always warry of suggestions that says can improve everything and make my 300cc bike be like 400cc by just tuning CVT...!!! 😅 

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Comments for N-MAX and Freego - the new Freego had vibration at the start, especially terrible at the start uphill.

 

I disassembled the CVT and saw abrasions from belt slippage at a distance of 2 cm on both half-pulleys. The belt did not come into contact with the bushing as it should be.

 

As far as I understand, Yamaha made a reserve to compensate for the full wearout of the belt from 22 mm to 20 mm.

 

But with such settings, you should always ride only on a completely wearout belt 😉

 

13 ° for a movable half-pulley and 12.5 ° for a fixed , in my case will increase the gap by 1,5 mm and the belt goes down to the bushing, not reaching 4 mm. There is no vibration or slippage and there is a  reserve for belt wear.

 

As the belt wears down, you can simply remove the washer between the bushing and the fixed half pulley to compensate for the wear  if it needed.

 

This is my personal experience only.
 

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