On two of my bikes, one 2 stroke & 1 four stroke I switched my chain tensioner pulley to chain idler from tandem bike. I got them from vintage bikes.(very easy to get & inexpensive) Its a steel small sprocket with stud that fits in existing tensioner bracket with no mods. On my 2 stroke I switched drive chain to bmx bicycle chain due to clearance issues & I like it much better. BMX chain is much smoother, quiter, less vibration, does not stretch & fits all sprockets great! No mods needed to change to BMX chain. I plan to switch other chain driven bikes that I have to bmx chains. However I have been using tandem bike chain idler for drive chain idler for over 100 miles & is working perfectly. It looks like it is going to be very dependable. I used to carry spare idler in my tool kit & now there is no need. Whatever chain you choose to run you can switch to tandem bike chain sprocket idler with no mods. Can also switch chains to bmx chain with no mods. Any questions please ask.