BMW F650 GS 2008 model Chain slapping

[jstark47]

Has your wife herd the chain slapping on her machine,

No, she has not.

what year is it?

It is a 2009 F650GS and it has the factory lower suspension option.

Have you ridden the bike ?

Yes I have, and I have not heard the chain snapping either.


In my experience, extra noise (slapping, snapping, or clicking) from chains can come from a worn or misadjusted (too loose) chain. I suppose a chain that's too tight can also make noise, but I wouldn't know by personal experience; I don't tighten chains that hard. If anything, chains on my bikes will be on the loose side.

I believe a chain that is set too tight will wear out prematurely. I wonder if that is the source of the problem you're having? Perhaps the chain was always too tight, and now it has worn out more quickly than it should have? How many miles are on your bike?

[HYPERR]

My bike was bought with the factory fitted lower suspension, the point i am trying to make is this, has any one got a similar problem with this model, or any bike for that matter. I believe its a design fault not a characteristic of the bike , this i believe is a BMW get out clause. There is no information given by BMW about it and i test road a new bike with the standard suspension which was fine so i had no idea that because the suspension was lower it would be any different. When i test road my bike i was told that the chain slapping would be put right in the service before i took delivery, probably the chain needed tightening.

I posted what it was on one of your other threads that you made on the exact topic. Your chain is slapping on the plastic chain guides on the swingarm; a sound most dirtbike riders are familiar with. I told you that your swingarm tilts down less than the regular suspension model which is probably what is contributing to the chain slapping which you assert does not exist on the regular suspension model. Yeah it's probably a minor design flaw; which BMW has plenty of and almost never admits to. The low suspension option was obviously an afterthought and the bike was originally designed with the longer shock.

How much do you weigh and where do you have the rear pre-load and the sag set at?

[vagne]

Well at last some one who knows what i am talking about. I have set spring preload , and damping rear wheel in accordance with the manual, for me 80 kg single rider and full tank of fuel. I have written to bmw who have told me that my manual does not include what they call characteristics so the chain tension is not in accordance with the manual , so i asked them about the preload and damping , Guess what !! they did not answer. So i am thinking that they may require a different setting. The chain has little or no play in it , its brand new as is the spocket as it had a recall and all works done under warranty by BMW. I welcome any suggestions.

[HYPERR]

Well at last some one who knows what i am talking about. I have set spring preload , and damping rear wheel in accordance with the manual, for me 80 kg single rider and full tank of fuel. I have written to bmw who have told me that my manual does not include what they call characteristics so the chain tension is not in accordance with the manual , so i asked them about the preload and damping , Guess what !! they did not answer. So i am thinking that they may require a different setting. The chain has little or no play in it , its brand new as is the spocket as it had a recall and all works done under warranty by BMW. I welcome any suggestions.

The reason chain slaps are more common on dirtbikes is because of the greater suspension travel and thus the need for the chain to be looser. Apparently BMW designed the bike to prevent this idiosyncracy from happening on the regular suspension model but didn't bother on the low suspension model. So the shorter rear shock is the culprit here. And since Mrs. Stark is not experiencing any chain slapping, I am going to guess that you do not have the rear sag set correctly. How much sag do you have? My hypothesis is that you currently do not have enough preload on your rear shock and if you increase it the chain slapping noise should decrease somewhat. Either way, setting the chain tension tight like a guitar string is not a good idea!