Not You Average "Clunk" - Wrist Twisters
 1Likes
  • 1 Post By mcromo44
 
Thread Tools Display Modes
post #1 of 12 Old 07-12-2017, 02:23 PM Thread Starter
Milites Gregarius
 
knicholas's Avatar
 
Join Date: Apr 2017
Location: --
Posts: 169
Rep Power: 1
 
Not You Average "Clunk"

Before I catch any eye rolls or witty(ish) jabs from you veterans, rest assured I've made ample use of the search function and ye old YouTube.

This question isn't about the Neutral --> First clunk - I love that clunk.

It's about a slightly more subtle and confusing clunk that doesn't always show it's face. Here's when it can happen:

Say I'm pulling into my driveway and am coasting the last dozen feet (yards divided by 3 for those across the pond). If I slowly let out the clutch, there will sometimes be a clunk. Or sometimes at idle waiting for a traffic light or in the morning before I drop into 1st and go, if I give it a quick throttle blip, then on the tail end of the blip (as the revs come back to idle) there will be a clunk. Both these clunks are not as audible as the loud 1st gear clunk but they strike a similar tone.

Any thoughts?

FYI I also adjusted my clutch cable so I have about 15mm of slack so I don't think its that.

knicholas is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 07-12-2017, 02:36 PM Thread Starter
Milites Gregarius
 
knicholas's Avatar
 
Join Date: Apr 2017
Location: --
Posts: 169
Rep Power: 1
 
Closest thing I found was this: https://www.wristtwisters.com/forums/...ing-70649.html

I wiggled my rear wheel on center stand and didn't get movement so I assumed bearings are fine. There an easy way to know about bearings and cush drive?

Maybe I'll tag @ewmin3m since it was his post

knicholas is offline  
post #3 of 12 Old 07-12-2017, 03:04 PM
McTavish
 
mcromo44's Avatar
 
Join Date: Oct 2007
Location: Calgary
Posts: 5,638
Rep Power: 1
 
Quote:
Originally Posted by knicholas View Post
Before I catch any eye rolls or witty(ish) jabs from you veterans, rest assured I've made ample use of the search function and ye old YouTube.

This question isn't about the Neutral --> First clunk - I love that clunk.

It's about a slightly more subtle and confusing clunk that doesn't always show it's face. Here's when it can happen:

Say I'm pulling into my driveway and am coasting the last dozen feet (yards divided by 3 for those across the pond). If I slowly let out the clutch, there will sometimes be a clunk. Or sometimes at idle waiting for a traffic light or in the morning before I drop into 1st and go, if I give it a quick throttle blip, then on the tail end of the blip (as the revs come back to idle) there will be a clunk. Both these clunks are not as audible as the loud 1st gear clunk but they strike a similar tone.

Any thoughts?

FYI I also adjusted my clutch cable so I have about 15mm of slack so I don't think its that.
There's lash in the system and my guess it's just a matter of which element, or combinations thereof that rear their head under certain circumstances, circumstances that will involve drive train loading and unloading.
Most likely it's a case of nothing wrong, as compared to something odd and observable.
The lash elements that spring to mind are:
Rear wheel cush drive.
Chain and sprockets.
Primary Drive Subsprocket.
Cumulative gear lash (aka cumulative gear mesh clearance)
Within the engine unit there is also the cam drive system, noting the chain tensioner on the trailing edge of the run down from the cam - but I doubt bad tension would cause a clunk or thunk sound.
I wouldn't be laying awake all night tonight stewing about it..........................
badmoon692008 likes this.

mcromo44 is offline  
 
post #4 of 12 Old 07-12-2017, 03:24 PM
Centurion
 
ewmin3m's Avatar
 
Join Date: Oct 2014
Location: Vancouver
Posts: 1,372
Rep Power: 1
 
Garage
For me it was the chain being loose; but you can also feel it slightly due to the bushings which have a bit of a shake in them. You could try to replace the bushings for higher quality ones (from hondas more sportier bikes), but I don't think its worth the cost.

ewmin3m is offline  
post #5 of 12 Old 07-12-2017, 03:34 PM Thread Starter
Milites Gregarius
 
knicholas's Avatar
 
Join Date: Apr 2017
Location: --
Posts: 169
Rep Power: 1
 
Thanks for the quick replies!

Quote:
Originally Posted by ewmin3m View Post
For me it was the chain being loose; but you can also feel it slightly due to the bushings which have a bit of a shake in them. You could try to replace the bushings for higher quality ones (from hondas more sportier bikes), but I don't think its worth the cost.
Ewmin, So the problem went away for you with adjusted chain? My chain is spot on adjusted (just adjusted it last week after a long trip) so I'm pretty certain it's not that. The damper (aka cush bushings) replacement wasn't worth it? I'm thinking maybe my bushings are a bit worn out so they just need replacing, which I'd do myself?

As per @mcromo44 's note, that's exactly what I'm doing haha - slacking at work and stewing over it. Don't want to cause undue damage to any parts if it's a simple weekend fix.

knicholas is offline  
post #6 of 12 Old 07-12-2017, 04:07 PM
LDH
Test Rider
 
LDH's Avatar
 
Join Date: Feb 2006
Location: by the ocean
Posts: 4,350
Rep Power: 1
 

Awards Showcase
Trackday Recognition Referral Award 
Total Awards: 2

Ya know what I vaguely remember this happening on my old 919 when I would pull in the clutch and coast up to a stoplight etc. Right before it came to a stop there would sometimes be an odd nudge inside the tranny somewhere. It's been way too long to remember all the details, but I seem to recall it negatively affecting the transmission when it did it like after the nudge if I clicked into neutral then tried to get back into first it took a tiny bit more effort than usual to get it to snick into first gear etc.

LDH is offline  
post #7 of 12 Old 07-12-2017, 04:13 PM
Centurion
 
ewmin3m's Avatar
 
Join Date: Oct 2014
Location: Vancouver
Posts: 1,372
Rep Power: 1
 
Garage
The "problem" was very noticeable with an older chain setup and older cush bushings. I went to the 17/44 kit from LDH and new bushings for the rear. It greatly minimized the effect.

My mechanic mentioned at the time that I could use higher performance (more precise fit?) bushings from the cbr1000rr but it wouldn't really be worth spending the money.

Quote:
Originally Posted by knicholas View Post
Thanks for the quick replies!

Ewmin, So the problem went away for you with adjusted chain? My chain is spot on adjusted (just adjusted it last week after a long trip) so I'm pretty certain it's not that. The damper (aka cush bushings) replacement wasn't worth it? I'm thinking maybe my bushings are a bit worn out so they just need replacing, which I'd do myself?

As per @mcromo44 's note, that's exactly what I'm doing haha - slacking at work and stewing over it. Don't want to cause undue damage to any parts if it's a simple weekend fix.

ewmin3m is offline  
post #8 of 12 Old 07-12-2017, 04:36 PM Thread Starter
Milites Gregarius
 
knicholas's Avatar
 
Join Date: Apr 2017
Location: --
Posts: 169
Rep Power: 1
 
Quote:
Originally Posted by ewmin3m View Post
The "problem" was very noticeable with an older chain setup and older cush bushings. I went to the 17/44 kit from LDH and new bushings for the rear. It greatly minimized the effect.

My mechanic mentioned at the time that I could use higher performance (more precise fit?) bushings from the cbr1000rr but it wouldn't really be worth spending the money.
Minimized but not eliminated? Interesting..

Well, I'll start with the simplest problem first then work my way through complexity. I heard tell that an improperly torqued front sprocket bolt can cause a similar noise so I'll start there. Then maybe I'll try just the bushings since my chain and sprockets have a fair bit of life left. If nothing fixes it, ii'll yank my own chain and @LDH you will likely have another customer soon

knicholas is offline  
post #9 of 12 Old 07-13-2017, 04:03 PM
The Cripple
 
Pvster's Avatar
 
Join Date: Nov 2009
Location: Phoenix
Posts: 8,765
Rep Power: 1
 
I had this same issue and experienced what LDH described. 2 things helped minimized it:

1. don't coast to a stop from 2nd gear or higher. Shift into first and preload the transmission again if coasting a distance to stop. This was where I started relying on engine braking a lot.

2. When the transmission start to feel off, I'd change the oil and noticed an immediate improvement. I know LDH has his contention regarding this statement so I don't know if it's just because I'm deaf and more sensitive to vibrations. But that's my experience.

Every once in a great while this would pop up and I'd stop being lazy with my shifting and it'd go away.

The 919 transmission really does beg to be abused. I was astonished at how much better it responded to demand on the track compared to the street and the transmission really shined in that environment.

IOW, you're over thinking this. Just a small, very few characteristic that this bike has. Don't worry about it, ride it.

Pvster is offline  
post #10 of 12 Old 07-13-2017, 04:15 PM
LDH
Test Rider
 
LDH's Avatar
 
Join Date: Feb 2006
Location: by the ocean
Posts: 4,350
Rep Power: 1
 

Awards Showcase
Trackday Recognition Referral Award 
Total Awards: 2

Quote:
Originally Posted by Pvster View Post
I had this same issue and experienced what LDH described. 2 things helped minimized it:

1. don't coast to a stop from 2nd gear or higher. Shift into first and preload the transmission again if coasting a distance to stop. This was where I started relying on engine braking a lot.

2. When the transmission start to feel off, I'd change the oil and noticed an immediate improvement. I know LDH has his contention regarding this statement so I don't know if it's just because I'm deaf and more sensitive to vibrations. But that's my experience.

Every once in a great while this would pop up and I'd stop being lazy with my shifting and it'd go away.

The 919 transmission really does beg to be abused. I was astonished at how much better it responded to demand on the track compared to the street and the transmission really shined in that environment.

IOW, you're over thinking this. Just a small, very few characteristic that this bike has. Don't worry about it, ride it.

1. YES, Now I remember!!!! That is exactly what was causing it. The coasting effect unloading the tranny. It was even worse if I snicked it into neutral prior to coming to a complete stop. I think we had this conversation previously on this forum too now that I give it even more thought

2. On the contrary I wholeheartedly agree. After experiencing firsthand how quickly that crapass Repsol oil goes off and makes the transmission notchy I am a firm believer in frequent oil changes for better shifting performance and engine life. It is even more important with the super expensive RACE Synthetic Engine Oils as it is a total myth that they last longer in a motorcycle engine with a shared transmission than conventional engine oils.

The last part is likely just the fact that all motorcycle transmissions like to be loaded up. The more time you spend either on the throttle or on the brakes the less time the transmission has to build up slack which alleviates driveline lash in the gear box, chain drive and cush drive hub.

LDH is offline  
post #11 of 12 Old 07-13-2017, 08:56 PM
Tesserarius
 
Join Date: Jul 2016
Posts: 671
Rep Power: 1
 
I agree with Pvster about being aggressive with a Honda transmission. A good rider can shift gears very fast. I hve a hard time beleiving that the automatic in the African Twin is faster.

I change oil every 3000 miles on the streetbikes, that l have.

Sniper-x is offline  
post #12 of 12 Old 07-14-2017, 12:24 PM Thread Starter
Milites Gregarius
 
knicholas's Avatar
 
Join Date: Apr 2017
Location: --
Posts: 169
Rep Power: 1
 
Excellent stuff - thanks all.

Oil has only been about 2k miles ago but maybe I'll give that a change to see what happens, it's inexpensive enough.

Cheers!

knicholas is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Wrist Twisters forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome