susuki z400

[Tri-Z_Jim]

The only solution is to set the front sprocket out from the engine more so that it sticks out past the case,unfortunately i dont know anyone thats ever done that.Theres just enuff room between the case and sprocket for the chain to fit thru when its on the sprocket.When the chain breaks or comes off it has alot of slack in it.Since the engine is still turning and theres no tension on the chain,the chain bunches up and tries going around the sprocket all at once.On top of the case getting smashed the chain usually bends the shift shaft also. Most of the factory case guards around the front sprocket are not built strong enuff to begin with. I think the factories design them to break if the chain fails so that we can spend a fortune on a new case.

[Dirtcrasher]

I machined one for my RM125 after I had a disaster. It followed the curve of the sprocket and picked up 2 - 6mm holes, similar to stock but I used 1/4 thick steel and twice as wide and used the longest screws possible to use the most threads. When I was running a junk rear sprocket it fell off again but nothing got ruined this time.