CBR650F CBR650F Clutch bang

[Yammer5]

Hi all

I have a 2017 CBR650F my clutch makes a reasonably loud bang or clunk when I engage 1st and the bike jumps forward slightly, is this normal please?
The video is fairly quite so it doesn’t sound quite as bad as it does when I’m doing it live.



Also if i pull the clutch in fully and try to very slowly go into first the gear the gear leaver bounces and sounds grindy, but if I do it quickly it goes in fine but with the bang noise as above, I’m not sure if this is just a bike thing or not, I can slowly put my car into gear with the clutch down with no issue, but I’ve only ever tried it on my bike today because I’ve been worried about the bang noise.

Cheers

 

[Drewster123]

If i was you I would stop doing that now you should never slowly put a bike into first gear it needs to be a short and quick /firm action. But yes it is perfectly normal every bike does it.

 

[Yammer5]

If i was you I would stop doing that now you should never slowly put a bike into first gear it needs to be a short and quick /firm action. But yes it is perfectly normal every bike does it.

Thanks for the reply, I’ve only tried putting into gear slowly once today as I was playing about with the gears due to the bang / clunk noise.

Is the bang / clunk noise normal too?

Thanks

 

[miweber929]

Seems normal rot me. Have you ever owned a motorcycle before? Just wondering if it's just something you are not used to.

What RPM is your bike idling at? Seems a tick high, you aren't giving it any gas, are you?

 

[Sunde]

Perfectly normal!

 

[Brammers]

Pull the clutch in for 20 seconds before going to 1st. It gives the clutch plates a chance to separate and will lessen the clunk.

 

[matt650]

My father in law has a pretty special race spec bike from around the year 2000. You should see the clunk that gives pushing into 1st gear. The bike practically moves about 2 feet!!

 

[Drewster123]

I like to know exactly where the noise is from just from a mechanical point of veiw

From my understanding the clutch plates don't completely separate when you have the clutch in,when you are about to select first gear.

So that means the input shaft is spinning still because the clutch is making it move. So becauce the input shaft is moving still it's not qwite lined up to the first gear. So the noise you hear is the dogs slamming into eachother. When brammers says about the 20 second thing that does accturaly carm the clunk. Thats becauce the plates have had time to separate more from the sticky oil film so that means the input shaft has had time to slow down . I think I'm right but not 100% sure but someone will correct me otherwise ahah

 

[Brammers]

Pretty spot on D @Drewster123

 

[miweber929]

First gear is also the largest gearing difference between the spinning engine, spinning transmission and gears so when you’re selecting the gear, you’re changing by a large margin everything spinning. You’ll still get a slight jerk if you go into second, but it’s not as pronounced.

 

[Yammer5]

Thank you for all of the replies guys, it’s much appreciated.

 

[silesianix]

Hi@All,

I have exacley the same issue. What is wondering myself, I have CB500F PC58 2017 no issue like that, CB650F yes, any idea, maybe oil change?