Knock Knock ....

[Stedders]

Hi,

My '03 GSA has been running fine until the other day when it made a funny single knock noise (like someone had hit the cyl head with a hammer!) as it started up. It was just the single knock and then it was fine. I've run it again since then with no problem but today it did the same thing - a single knock and then normal. I appreciate its difficult to diagnose these things over the computer but any ideas? Having had a look around the forum I'm wondering if it might be the onset of big-end problems? What are the usual signs to look out for?

Cheers

 

[cookie]

bit of detonation as it starts perhaps?

big end will knock under load. high gear, up hill. it'll do that any time when hot usually.

 

[snoopy]

Mine does it occasionally - I heard the starter motor is the problem, possibly lost a tooth.

 

[ciderman gs]

could it be the cam chain tensioner not taking the slack quick enough is it after ithas been hot, on the side stand has the oil been changed

andy

 

[Tony T]

Mine has done what sounds like the same thing for the last couple of years. Usually happens when hot and sounds like a "crack", either a spark jumping a gap or pre-ignition, just the one crack, starts ok runs ok nothing else. I have never managed to find out what it is. If yours is the same symptom I would definitely rule out a major internal problem. Hope this helps to calm the fears?

 

[Stedders]

Hey, thanks everyone - big load off my mind as it sounds like nothing too serious ... I've also noticed when on the side stand and re-starting when hot it makes the same noise for a very short while - seems to run fine otherwise. As I've only done a 1000 miles since I got it I'm still getting to know the bike's 'character' (sounds and all)! I expected it to be a bit noisey, clunky gears, etc (I also have a CBR600 which is a diff ride altogether!) - and quite like that - its just knowing which noises are right for the bike I guess - its easy to get spooked. Luckily its under the used BMW warranty till December(having the gear box oil seal replaced in a couple of weeks after noticing the final drive gaitor had oil on it ... so was a bit worried I'd bought a donkey!) so I should have plenty of time to put some more miles on and any probs to be sorted.

Cheers again for the advice - its times like this the UKGSER forum is worth its weight in gold! I can get back to enjoying my bike now!

 

[Colban]

Would it be worth trying a tank of super-unleaded fuel to see if its pre-ignition.Bit too much ignition advance?.

 

[Steptoe]

It's lash in the cam chain tensioner. It doesn't do it everytime, as it all depends on the position of the internals when the engine stops.

 

[Stedders]

Hi Steptoe!

Thanks for the info - will get the garage to check it out/replace the tensioner when it oges in for the oil seal. Thanks again for allaying fears that my bike was about to seize on me!

 

[Steptoe]

!

Thanks for the info - will get the garage to check it out/replace the tensioner when it oges in for the oil seal. !

Nothing to check out or replace. Any GS can do it at any time.

Just ride it.