May be ok for final drive chain, but from my experience I won't bother to try it. I tried to use this to jam the clutch basket to the main gear to remove the main gear nut. The "jammer" broke clean in two.
A well thought out idea that makes some tasks one-man instead of two. Take your time when you're considering where to use the jam, and I would recommend slowly applying torque until you get your result. And for heaven's sake, remember to remove the thing before you put your case cover back on!
This is the most cost effective tool in my stash. This little shark will PROPERLY lock gears without risk of damaging the gears, shafts or bearings. Don't jam coins or other make shift crap between your gears. Those methods cause the gears to try to separate and will put a lot of pressure on your shafts and bearings. This little bugger has the proper geometry to properly lock your gears for dis-assembly or assembly. Great to see a simple, inexpensive tool can be so useful.
Borrowed my brothers gearjammer to replace the crank seal in my bike. Worked great, much better than the nickel I used the first time I took it apart. Ordered my own when I placed my next order. Would recommend to everyone!
This is one of those situations where you could probably improvise something else to stop the gears from turning while you remove or torque nuts. But, it is really nice to have the right tool that accomplishes the task simply and quickly. The only downside to this tool is the cost; it is relatively expensive for something so simple.
If you do your own engine work, this is a great tool. Even with the engine partially disassembled on the bench you have a means tolock up the crank or gear train for disassembly or reassembly. It really comes in handy and is so much easier to use than a scrap of aluminum. I recently used it to replace the crank in a friends Yz250F. Great tool.