"Fragile" Gearbox's.

[Curly3]

A bit different this one.
I've started a project to turn a road going T20 250 Suzuki into a Dirttracker/Flattracker for pre70.
An issue has come up regarding the gearbox, namely that the connecting gears are not hardened, but Copper coated to act as a "Weak Link" in the transmission line.
Does anyone know of a similar issue in other gearbox's and how serious is it?
Obviously Dirt Track racing is tougher on gearbox's so I'm interested  in some feedback.
Steve

[pmc57]

Normally the copper coating is applied in the heat treatment / hardening stage to stop certain areas from being hardened. It's similar to the typical con-rod where they copper coat everywhere except the big and little ends where hardening is required.

Maybe the gears you're talking about have been copper coated to maintain the integral strength and toughness to the body of the gear but the teeth have been left uncoated and induction or flame hardened to the required Rc hardness for good wear resistance.

I would think not a weak link but rather a good manufacturing practice.

[VMX60]

Worth checking into the t20 roadrace guys pretty sure the hot setup with high HP was to fit the later t250 /350 model gearbox assy into your cases
Plus the later box had a better shift update on the drum

Cheers

[suz125]

http://www.t20suzuki.com/

[Curly3]

Thanks suz125, I stumbled across that site myself just after posting this question.
He, Adrian Baker, is definitely the T20 guru and there is some great info on there.
Steve

[chrisdespo]

my t20 was far from fragile rode the wheels off that poor little suz and just couldn't break anything i think my nephew is doing a road race build on bike at the moment.