Nmax shuddering

[1happykamper]

Good morning! My 2023 Nmax with only 7k km starts just fine first thing in the morning. But moving is another story 

 

A huge shuddering occurs before the bike starts to move... Then everything is fine. Until I stop... Then.. Shuddering again. 

 

 

It feels exactly like a manual clutch in a car that's not engaging correctly 

 

I took it to the Yamaha dealer today but they are too busy. Come back tomorrow 

 

A comment the dealer made was that he's seen this problem before with fat men. Thai directness 555. I'm 187 cm and 105 kg. Is this cause legit? 

 

Can the belt.. CVT?.. can it be adjusted? Or new normally needed? 

 

EDIT.. but when the bike is normal temperature everything is smooth again on take off. 

 

 

[Agusts]

It's the auto clutch at the back of CVT, the clutch shoes and clutch housing bell. Though it's very rare in Yamaha..., but I have seen this on almost every heavy Honda scooters, ADV 350 and Forza 300/350...

 

I myself and 2 other friends all currently have this issue. Dealers just open and clean it, problem comes back after a few weeks. On my previous Forza I have used aftermarket Bell and Carbon shoes, it worked perfectly for 25,000km, then one shoe broke, changed back to OEM shoes and worked perfectly until I sold it. 

 

Just yesterday ordered aftermarket Bell to change on my current Forza. This time I am leaving the OEM shoes and not changing it. I think changing the Bell alone resolves it - will see... 

 

As you have warranty, have to play with what Yamaha says, maybe ask them to change shoes and bell to OEM on warranty, it should work for another 7000 km...! 

[VocalNeal]

3 hours ago, 1happykamper said:

Good morning! My 2023 Nmax with only 7k km starts just fine first thing in the morning. But moving is another story 

 

A huge shuddering occurs before the bike starts to move... Then everything is fine. Until I stop... Then.. Shuddering again. 

 

 

It feels exactly like a manual clutch in a car that's not engaging correctly 

 

I took it to the Yamaha dealer today but they are too busy. Come back tomorrow 

 

A comment the dealer made was that he's seen this problem before with fat men. Thai directness 555. I'm 187 cm and 105 kg. Is this cause legit? 

 

Can the belt.. CVT?.. can it be adjusted? Or new normally needed? 

 

EDIT.. but when the bike is normal temperature everything is smooth again on take off. 

 

 

 

Dust in the clutch. It needs a good high speed run at 80 kph and over to blow out all the dust.

[1happykamper]

80 kph? I'll pee myself. Sixty is my top speed 😂😂😂

 

I'll get in a highway tomorrow. Try that. Worth a shot. Thanks 

[VocalNeal]

On 5/15/2025 at 2:58 PM, 1happykamper said:

80 kph? I'll pee myself. Sixty is my top speed 😂😂😂

 

It sounds like your riding style could best be described as ? relaxed. This could result in the clutch facings becoming glazed. 

 

Your clutch could also do with a few aggressive accelerations from a stand still.  Find a deserted space of road and do a few full throttle pull aways from a standstill. Up to you 60 kph comfort zone will do for this. 

[Agusts]

Or you can hold both brakes strong, then rev the throttle to about 4k or 5k for a a couple of seconds, do it 2 or 3 times....

 

Or open the clutch, clean and sandpaper the shoes... 

 

But all of these only fix it for a few days, after that it will be back again. Been there done that...! 🙄

[Agusts]

My clutch housing bell arrived today, I used this on my previous Forza. 

 

The small holes and groved inside the bell which are added to the standard (Honda) bell makes it a lot better, small holes stop it getting warm an warped, also exit resin/dust. The groves catch the shoes, stop it slipping... 

[VocalNeal]

Do you have a 300 Forza? I like the groves. But they may wear the shoes quicker. 

 

My scoot doesn't need extra grip and I like a bit of slip on takeoff to keep the revs up. Currently using sintered shoes.

[Moonlover]

On 5/15/2025 at 2:47 PM, VocalNeal said:

 

Dust in the clutch. It needs a good high speed run at 80 kph and over to blow out all the dust.

Sounds plausible. I have an Aerox and although most of my trips are around the rural lanes, I do like to get it out on the main highway now and then and give it a good blast. 

 

I've had the bike nearly 4 years now and I've never had clutch issues, so I guess it's a worthwhile practice.

[Agusts]

1 hour ago, VocalNeal said:

Do you have a 300 Forza? I like the groves. But they may wear the shoes quicker. 

 

My scoot doesn't need extra grip and I like a bit of slip on takeoff to keep the revs up. Currently using sintered shoes.

 

I had old model Forza 300 2016 before and used it on that one, now I'm putting it on Forza 350 - these have 5 shoes instead of previous 3, Honda has tried to improve this issue, but unfortunately it didn't work...! 

 

You're right about the effect of groves. On my old Forza I also changed to Carbon shoes (they also have Copper). It worked for 25,000 km without issue. But one day I did a full throttle at green traffic light, and one of the shoes broke, the clutch was grabbing, and the bike would stall when stopped. But I could still ride it, only problem was when full stop...! 

 

I manage to get to a Honda dealer, they opened it and changed the shoes to their own OEM, this worked perfectly again for about 10,000 km or so until I sold the bike. When they opened I noticed the groves were still on the bell, almost intact...! 

 

So I realised the OEM shoes work with this aftermarket bell, no need to change. Hence I'm only changing the bell this time. 

 

And before I do all this I had opened, cleaned, cleared dust, sandpapered the shoes and so on, but to no avail. 

 

This time I check more frequently and maybe change the shoes to prevent them breaking like last time, but the aftermarket bell is my only solution that I know works ... 

 

With sintered shoes I'm guessing you mean Copper version they sell..., right.. ? I wonder if that is stronger than Carbon that broke on me...! 🤔 So according to your experience the Copper shoes without aftermarket bell solve this issue as well...? Have you had it over say 10,000 km, because this problem starts around 6000/7000 km on new Honda bikes give or take... 

 

Yamaha owners never reported this until this post. As for Aerox my friend has 96,000 km on his, still same shoes and bell...! No issue... 😎

[VocalNeal]

12 minutes ago, Agusts said:

on Forza 350 - these have 5 shoes instead of previous 3,

 

This is why I asked. The 350 has a larger bell/clutch assy. I was not aware it didn't improve the system.

[VocalNeal]

14 minutes ago, Agusts said:

With sintered shoes I'm guessing you mean Copper version they sell..., right.. ? I wonder if that is stronger than Carbon that broke on me...! 🤔 So according to your experience the Copper shoes without aftermarket bell solve this issue as well...? Have you had it over say 10,000 km, because this problem starts around 6000/7000 km on new Honda bikes give or take... 

 

Mine is only 120-ish. I think the copper? ones I am using on a Honda are actually for a Yamaha but they fit. Same bell diameter etc.. I didn't go carbon as I don't "race" I just Zoom around town. I wanted to get the system to slip a bit more to get the revs up and they came with their own springs. I'm not sure how many kms on them but they are still in good condition. They are black now not a gold/sand colour as they are covered in belt dust.

[Agusts]

1 hour ago, VocalNeal said:

 

Mine is only 120-ish. I think the copper? ones I am using on a Honda are actually for a Yamaha but they fit. Same bell diameter etc.. I didn't go carbon as I don't "race" I just Zoom around town. I wanted to get the system to slip a bit more to get the revs up and they came with their own springs. I'm not sure how many kms on them but they are still in good condition. They are black now not a gold/sand colour as they are covered in belt dust.

 

Is 120-ish the price....? For each shoe...! 

 

Yes, when buying aftermarket bell, must specify Forza 300 or 350, must be different... 

 

When I was buying shoes I asked the seller which is better, Carbon or Copper, he said Copper stand to higher temperatures, and good for very high speed..., he recommended Carbon to me...! 

 

Maybe in Thai hot weather, and my touring normally at 120kph, I should try Copper..., interesting you got spring too, send me the Lazada / Shopee link if available, my Lazada supplier does not include springs...? 

[VocalNeal]

15 minutes ago, Agusts said:

Is 120-ish the price....? For each shoe...! 

 

 

No 120-ish is the capacity of one of my bikes.😁

 

15 minutes ago, Agusts said:

and my touring normally at 120kph,

 

At much less than 120 kph the clutch is already fully engaged so no slip or heat generated. There are a couple of cam action clutches that use mechanical force to put more pressure onto the shoes to improve grip. But maybe not yet for Forza 350