Gearbox goes clunk, rear wheel locks

[FilthyLuka]

howdy all

Well, today, i got up in the mornin to go for a nice ride out warkworth way... my brothers bike didnt start (dead battery) and for some reason, my bike (gn250) refused to go backwards... Clutch in and first selected, just didnt want to roll back, neutral selected, no difference... hmm, odd. So i turn on the engine, select first and start moving forward up ze driveway, about a meter up i hear a loud KACHUNKERTA and then it ran as normal... Go up the road, turn around, go back. slow down, select second (i was goin 20, i checked) and started engine braking, the it goes rattley clickitie klunkitie, i pull the clutch in, and it continues. Start going down the driveway, clutch in (still in second) and the gearbox just went THUNK and the rear wheel locked. Thought "aah feck," selected first, went to take off, no problem. Got home tonight, picked up the bike and it wheels around fine. Goes back, and forward as it should...

What the f#ck? anyone got any idea what it might be? Not the engine i guess cause it didnt care if the clutch was in or not...

Thanks

Daenis

[FROSTY:Me]

Ok theres a few things it could be. Lets try the KISS principle.
Bike on Main stand. In neutral. Spin the back wheel see if ya hear a banging and clanking. Look at the back brake area as well as around the front sprocket.
Start there before looking deeper

[tri boy]

Worn/dry/tight spot in chain maybe.

[FilthyLuka]

Worn/dry/tight spot in chain maybe.

i clean and lube my chain regularly, but it is coming up for replacement sometime soon, ill check it tomorrow.

Ill try the spinning of ze rear wheel thing aswell and post back

thanks guys

Daenis

[FilthyLuka]

found the problem. The front sprocket is f0cked, good thing i have a pristine shiny new one at home

thanks guys