Engine oil drainage bolts are usually regular thick bolts that screw in place and come our without much of a fuss. But someone at Hero decided to do something different for the engine on the Karizma. This!
This aluminium threaded cap is extremely weak and snaps on demand leaving you with something like this.
I’m told that the Karizma engine valve covers use the exact same threaded cap. So if this happens to you on the road and you don’t have a spare (I’m carrying one from now on) then you can use the one from the valve cover and somehow tape the valve cover hole. That way you will at least be able to move a head to a Hero dealer or spare parts shop. Having said that, this part is not commonly found. I tried two Hero dealers and finally got it from the third.
One look at the cap’s thickness and you will get an idea about how strong this thing is. No mechanic I’ve seen working on a Hero motorcycle uses a torque wrench to torque this to the right amount. So sooner of later this is going to snap.
I understand that the reason for using aluminium is because its weaker than cast iron. So its better if the cap’s thread slips instead of wrecking the engine thread, which would be a far bigger problem. But then the cap should have been made thicker or stronger so that the hex head doesn’t shear.