Loud Knock when starting

[Broox]

OK I have been riding my bike all season, and i even rode it last night. But when i went to start it this morning, it was trying to start and i hurd a very loud KNOCK and wouldn't start. It did this about three times. Then I started getting the rapid little knockings because the battery was getting low from trying to start it. So I fully charged the battery, and tried to start it up again, and once again got the very loud knock and wouldn't start. I have no clue what this could be, PLEASE HELP!

[rayshon]

post a video

[gtscott]

might be hydrolocked, pull out sparkplugs and see if it will turn over

[kml.krk]

I believe that I recognize the sound you are describing. I had the same thing happen last winter. It was caused by few things. Most important was weak battery. It was holding charge and providing juice but not enough to properly start the bike. What I also notice was that the knock did not appear when I used NO choke. Try starting your bike with no choke, it will probably not start but just see if it will knock or not.

get you battery tested, my battery turned out decent on the test but not perfect and it was causing that knock.
I spent countless hours trying to figure out the cause. I was suspecting sticking valve, pre ignition, messed up timing.

good luck

edit: if you can't get your battery tested then try jumping from your car or from jump starter. In my case this made me figure out that battery was at fault as the knock did not happen when jumped from the jump starter.

[kml.krk]

hey, I found my thread: http://gstwins.com/gsboard/index.php?topic=55345.msg626428#msg626428
there is a lot of good info there, tips and things to check

and here is a video I took back then that represents the noise: http://www.youtube.com/watch?v=I0VnZ7k99mY

[ryott52]

Maybe a bad case of Goat's?

[The Buddha]

Ggggggggggggggggggoooooooooooooooaaaaaaaaaaaaaaaaaatttttttttttttttttttsssssssssssssssss the Buddha variation ...

Its like tumor but when caught @ first instance can be removed and nothing else goes with it ... but wait and its a mess ...
Yea swap the starter clucth and check the rotor for teeth marks ... if yo usee too many maybe see if you can replace it too.
Cool.
Buddha.

[badguy]

Not sure it's goats...I had that problem, and it started without much issue. If it's making a knocking sound without starting, that may be something else. Or maybe it's the starter clutch along with another problem that won't allow it to start