clunks on every gearshift

[sezan]

my bike is yamaha r15 V4 wet/slipper clutch assist. my problem started when i put liqui moly Mos2 oil additive with the motul 5100 10w-40. riding the bike after oil change i heard instant loud clunk in every gear shift. before there were no clunks and gear shifts were buttery smooth. then within 100kms of riding i drained the engine oil and put liqui moly 10w-40 semi synthetic and still hearing the loud clunk and so far none of the yamaha dealerships found the problem .

Once the bike get into working temperatures (~ 100 C ) I hear a noticeable clunk while shifting gears.

This will not happened if the bike is still cold.

The sound is mostly notice in this shifts order :

Up shifting :

N>>1 - most of the time I hear the sound

1>>2 - 90% of the time

2>>3 - Always

4 & above no sound whatsoever - All good.

Down shifting:

4>>3 - most of the time I hear the sound

3>>2 - 90% of the time

please help what’s wrong

[Mississippi Bullfrog]

Motorcycles use different oils from car engines. They don't have friction reduction agents due to motorcycle clutches running in oil. 

 

I suspect that additive is not recommended for motorcycle engines. If it has soaked into the clutch plates changing the oil won't cure it. 

 

You may need to replace the clutch discs. 

[sezan]

21 minutes ago, Mississippi Bullfrog said:

Motorcycles use different oils from car engines. They don't have friction reduction agents due to motorcycle clutches running in oil. 

 

I suspect that additive is not recommended for motorcycle engines. If it has soaked into the clutch plates changing the oil won't cure it. 

 

You may need to replace the clutch discs. 

do i only need to change the clutch discs or also the pressure plate? is there any tips to detect the oil additives being absorbed into the clutch discs visibly? thanks  

[sezan]

24 minutes ago, Mississippi Bullfrog said:

Motorcycles use different oils from car engines. They don't have friction reduction agents due to motorcycle clutches running in oil. 

 

I suspect that additive is not recommended for motorcycle engines. If it has soaked into the clutch plates changing the oil won't cure it. 

 

You may need to replace the clutch discs. 

do i only need to change the clutch discs or also the pressure plate? is there any tips to detect the oil additives being absorbed into the clutch discs visibly? thanks  

[exportmanuk]

I would suggest only the friction plates  as the driven plates are metal and can be cleaned  you will also have to clean the clutch basket.   Having put car engine oil into a bike once  I had to replace the friction plates  before it would work properly    Also the higher you go up the gear box usually the easier it is to change without using the clutch at all this would account for your changes into 4th being no problem

 

Edited January 14, 2023 by exportmanuk

[TimR]

How about check chain tension ? 

 

Chain elongates as gets warmer hence more slack increasing the lack of pressure on gearbox which can create a clunk when gear changing 

 

Also check chain condition for damaged rollers 

 

Check sprocket conditions also

Edited January 14, 2023 by TimR

[sezan]

2 hours ago, exportmanuk said:

I would suggest only the friction plates  as the driven plates are metal and can be cleaned  you will also have to clean the clutch basket.   Having put car engine oil into a bike once  I had to replace the friction plates  before it would work properly    Also the higher you go up the gear box usually the easier it is to change without using the clutch at all this would account for your changes into 4th being no problem

 

thanks a lot mate. i was looking for the exact reason why. i believe finally got it figured out. On monday i’ll take it to the service centre and change the clutch discs. 

[sezan]

2 hours ago, TimR said:

How about check chain tension ? 

 

Chain elongates as gets warmer hence more slack increasing the lack of pressure on gearbox which can create a clunk when gear changing 

 

Also check chain condition for damaged rollers 

 

Check sprocket conditions also

the mechanic at the yamaha service centre did it all and still couldn’t figure out what’s the actual thing that was causing this 

[Guest]

Was it the motorcycle liquimoly additive? That's meant to be safe with wet clutches.

[sezan]

5 hours ago, goat said:

Was it the motorcycle liquimoly additive? That's meant to be safe with wet clutches.

i also knew the same but i don’t know why this happened. please see the photo and let me know if this what you’re talking about 

[Mississippi Bullfrog]

2 hours ago, sezan said:

i also knew the same but i don’t know why this happened. please see the photo and let me know if this what you’re talking about 

The spec sheet specifically says not suitable for wet clutches. 

[Guest]

2 hours ago, sezan said:

i also knew the same but i don’t know why this happened. please see the photo and let me know if this what you’re talking about 

This is the bike one https://www.liqui-moly.com/en/gb/motorbike-oil-additive-p000022.html#1580

 

They do a car one and a bike specific one. My greek isn't what it used to be but that one you have looks like the ordinary car one? which wouldn't be ideal in a bike wet clutch 

[sezan]

10 minutes ago, Mississippi Bullfrog said:

The spec sheet specifically says not suitable for wet clutches. 

it said 2% can be added in a wet clutch. i did that accordingly. or maybe you’re right. this product is just not suitable for bikes

[sezan]

12 minutes ago, goat said:

This is the bike one https://www.liqui-moly.com/en/gb/motorbike-oil-additive-p000022.html#1580

 

They do a car one and a bike specific one. My greek isn't what it used to be but that one you have looks like the ordinary car one? which wouldn't be ideal in a bike wet clutch 

yes that’s the bike one. but the one i put its said 2% of the engine oil capacity can be put into wet clutch and yet this clunk issue happened

[Mississippi Bullfrog]

For all 4-stroke gasoline and diesel engines, with or without turbochargers. Miscible with most commercially available motor oils. Safe for use with catalytic converters and particulate filters (GPF/DPF). Not suitable for the use with wet clutches! Contents (300 mL) is sufficient for 3–6 Liters (0.8 gal. to 1.6 gal.) motor oil. Shake well before use.

 

Application

[fastbob]

The amount of oil and or additive that is " Absorbed " by Clutch Plates is negligible in my opinion . Good luck though .