Added,,
The drum will basically oscillate badly, when having end play, as the chain makes it move latterly any way, especially if you don't have your chain alignment ''tits'' 100%, and your sprockets aren't true.
That in turn will wear out the bushing end I.D.'s real quick.
The drum will basically oscillate badly, when having end play, as the chain makes it move latterly any way, especially if you don't have your chain alignment ''tits'' 100%, and your sprockets aren't true.
That in turn will wear out the bushing end I.D.'s real quick.
The fiber washer that is inserted between the dust cover snap ring and sprocket snap ring is designed to mitigate most of that play. You need some end play so you don't prematurely wear the bushing. In normal use with a decent chain alignment, it does not oscillate, nor cause premature wear on the bushing. Premature being the operative word, since that bushing does need replacement when it wears out.
The only things that cause "premature" wear on the bushing is a clutch brake or a chain that is too tight, or not lubricating the bushing.
These clutches should not be cinched or captured to the PTO, but allowed a bit of lateral movement on the PTO against the PTO shelf, and retaining bolt and washer. This means that your chain alignment does not need to be "tits". In other words, if you have "set screws" in your clutch, remove them. He hasn't used set screws in his clutches for a couple of years now, so any new clutches with them, were shelf stock.
The green spring is an excellent choice for adult riders and vintage mini bike engines. I am also using that set up on a modified flat head engine with a bit more power that has allowed me to "cheat" a little bit on the gear ratio. If I weighed half of what I do, a tighter spring wouldn't matter. (Note the Adult comment) All I use are green springs now, but I do have some clutches I will be using with a black spring for testing later on. I do not use more powerful OHV engines, so I really benefit from some higher RPM engagements.
I have a bunch of fiber washers I found in the UK. They're stupid money on Ebay. I tried doubling them up to reduce end play, and got heat. If you need some, let me know. They are .002" thicker than the stock ones.
Max Torque has been in the business of making these clutches for race karts and mini bikes since 1957, and has learned quite a bit about what works and what does not. We all have opinions, and if you feel Jim has mis-engineered his clutches, or would benefit from running shims, why not give him a call, or shoot him an email and let him know? He will also work with anyone to provide solutions for unique applications.