Knackering vibration low rev

[tordfo]

Hi!


Any ideas what could be wrong? It happens only at about 2000rpms. I cant notice it in neutral (when just revving), but in all gears when driving.


Sound like "DRRRRRRRR" and you can both hear and feel the "knockering vibration" in those low revs, and just when touching maybe 2500/3000 rpms everything floats like a boat again...


It is fitted with a sport exhaust, and I dont think it is retuned in that regard. Could it "just" be in need of retune or maybe carburators need syncing? Im pretty new in motorcyckling so i dont really know what to look for. I have just checked the front sprocket and everything seems ok there. There is new chain and sprockets all over...


I might mention that i feel there is a lot (to much?) slack when going on/off throttle/shifting, but chain and all seems to be within limits. I have not checked the cush drive rubbers.. (my thought).


Any ideas?


Best Regards from Norway

[CRH]

does it do it in any particular gear? ......like second mabe??...

[NotAnotherHill]

Mine started doing that and it was the nut that had come loose holding on the front chain sprocket.

[ade the blade]

it may be no more than just the chain too tight. its obviously a moving item ( no noise when stopped and revved). is the chain dry-ish? it will make weird noises like that as it rides over the top end of the swing arm protector just before hooking up with front sprocket. worth a look.

[darrsi]

If chain's too tight you'll only feel it on left side, it feels lumpy on the foot.
I feel it when it needs a top up of chain spray, once done it's okay.

[tordfo]

Hm. Thanks for tips. The chain is not to tight (or dry, i guess, ref manual), and its not only in 2nd gear (same thing in all gears!)... I have checked the front sprocket and everything looks allright... It feels like something is loose (engine wise???), but cant figure out what/where....


I guess i could try loosen or tighten the chain just to see if there is a different.. Just has to wait for the rain to stop pouring...

[darrsi]

You're not on about cam chain noise are you?


Because that noise stops when the clutch is pulled in.        :eek (the voices made me say that, please ignore this advice) :eek

[Fazerider]

From the fact that the problem occurs in all gears, but is OK at higher revs it sounds as if the next thing to do is balance the carbs. If that doesn't help, take a look at the spark plugs to see if there's any sign of a cylinder misfiring.


If the carbs are out of balance, that will make low-speed riding jerky.
Another possible cause of a sloppy throttle response when riding is loose throttle cables. Lift the tank and have a look at the amount of free play, there are adjusters where they attach to the centre of the carb assembly.


Another cause of snatchy throttle response could be a knackered clutch, the friction and drive plates could possibly cause enough wear on the basket to become sloppy, though in my experience it's a pretty reliable unit.


Riding style may be a factor. There will always be some slop in the drive train which you feel as you as the throttle is opened and closed, this can be overcome by gentle use of the back brake to keep the upper run of the chain taut before you apply power. This technique makes a huge difference in slow corners.

[Skippernick]

It might be as simple as a connection block behind the speedo buzzing in contact with something else. You are describing the same symptons as mine and it turned out to be that.
Nick

[ade the blade]

You're not on about cam chain noise are you?


Because that noise stops when the clutch is pulled in.

does it ???????????

[CRH]

[quote author=darrsi link=topic=3575.msg29132#msg29132 date=1340419964]
You're not on about cam chain noise are you?


Because that noise stops when the clutch is pulled in.

does it ???????????
[/quote].........ade?......yes clive?.....ime with you on this one mate?? :rolleyes .....cheers clive?.....no probs mate!!!! :lol

[darrsi]

Sorry, have i got that totally wrong, i had a very late night/morning, and still suffering?


You're making me think now........and it hurts to think at the moment  :rolleyes

[dx408]

Does it happen when you rev at stand still ? or is it only when you are moving ? or both ?
If stationary rule out the chain. if moving and stationary ?????????
Sorry

[tordfo]

Thanks for tips guys. Still pouring down here so i havent got out to check wheel alignment and such..


I have googled cam chain noise and i cant say that i recognise anything. When stationary everything sounds/feels normal to me..


Speed or gear make no difference. Problem occurs in all gears, all speed, but only in this 2000 ish low rev range when using throttle.. When just gliding (cant come up with a more suitable word) there is no sign of it.

[ade the blade]

Thanks for tips guys. Still pouring down here so i havent got out to check wheel alignment and such..


I have googled cam chain noise and i cant say that i recognise anything. When stationary everything sounds/feels normal to me..


Speed or gear make no difference. Problem occurs in all gears, all speed, but only in this 2000 ish low rev range when using throttle.. When just gliding (cant come up with a more suitable word) there is no sign of it.

ok lets try and think logically about all this.........i know certain peeps think that is beyond my capabilities ( ya know who you are :lol :lol )

• only occurs at 2000 rpm......is that under load only ( moving) or at idle and revs held at 2000?
  
• when you say gliding.......do you mean pulling in the clutch and just coasting along?
  

if answer to revs is under load only, then that points at carb balance or possibly sticking carb slider (s)...te amount of movement on the sliders when revved stationary is minimal
ifanswer to gliding is yes, then a clutch issue to be to blame. also bear in mind, when bike is accelerating, top run of chain is under the most tension, and the reverse as you shut down throttle ( engine braking ) pulling in clutch and holding it in cancels out both. hth a licle bit

[CRH]

[quote author=tordfo link=topic=3575.msg29192#msg29192 date=1340471309]
Thanks for tips guys. Still pouring down here so i havent got out to check wheel alignment and such..


I have googled cam chain noise and i cant say that i recognise anything. When stationary everything sounds/feels normal to me..


Speed or gear make no difference. Problem occurs in all gears, all speed, but only in this 2000 ish low rev range when using throttle.. When just gliding (cant come up with a more suitable word) there is no sign of it.

ok lets try and think logically about all this.........i know certain peeps think that is beyond my capabilities ( ya know who you are :lol :lol )

• only occurs at 2000 rpm......is that under load only ( moving) or at idle and revs held at 2000?
  
• when you say gliding.......do you mean pulling in the clutch and just coasting along?
  

if answer to revs is under load only, then that points at carb balance or possibly sticking carb slider (s)...te amount of movement on the sliders when revved stationary is minimal
ifanswer to gliding is yes, then a clutch issue to be to blame. also bear in mind, when bike is accelerating, top run of chain is under the most tension, and the reverse as you shut down throttle ( engine braking ) pulling in clutch and holding it in cancels out both. hth a licle bit

[/quote]... IME WITH THE BLADE ON THIS ONE!!!!!!..ATB IS THE MAN!!!!!

[darrsi]

Are you two not even gonna slaughter me ???


You're way too polite!!!


Good on you lads.......respect is due.......  :lol :lol :lol

[red98]

Are you two not even gonna slaughter me ???


You're way too polite!!!


Good on you lads.......respect is due.......  :lol :lol :lol

dont worry darrsi........"forum heckling" is just around the corner...... :rolleyes :rolleyes :rolleyes

[CRH]

[quote author=darrsi link=topic=3575.msg29225#msg29225 date=1340501251]
Are you two not even gonna slaughter me ???


You're way too polite!!!


Good on you lads.......respect is due.......  :lol :lol :lol

dont worry darrsi........"forum heckling" is just around the corner...... :rolleyes :rolleyes :rolleyes
[/quote]...

[ade the blade]

Are you two not even gonna slaughter me ???


You're way too polite!!!


Good on you lads.......respect is due.......  :lol :lol :lol

good lord no, darrsi.....i for one am very selective. can`t speak for anyone else mind :rolleyes . no,i respect the fact you obviously had a bit of a `senior moment` there with the cam chain suggestion and apologised instantly for that. however, had you not been a real man and owned up to your error, then i`d have said quite honestly that you`re thick as sh&te !!!!!!!!!!!!!!









































only jesting mate............i know you can take it........if not :moon :moon :moon :moon