Years ago Tony Hall used to produce these. They became harder to find than chicken lip-socks (rarer than hen’s teeth). Ivan Hoey (Australia) began producing these once more some years ago. Fits direct to the original clutch basket.

I scored a set and have been running them ever since. Love them. 3 fewer teeth on the primary gear, 5 more on the drive gear. Increases the transmission output while decreasing crank rotation.

Original        … 27:72 … 2.66

Ivan +20%  … 32:69 … 2.16

Together with Terry’s vescanite clutch dampers. The vescanite dampers don’t break like the springs.

Two of the better modifications I’ve done.

 

original primary gear … with vescanite dampers

 

 

 

high ratio primary gears … with vescanite dampers

 

Ivan has just produced a new batch. Improved. The inner bush has been replaced with a needle bearing.

 

Ivan’s new set … + needle bearing

 

This is a small run. If interested he is now taking orders. Requires a deposit. Email contact here … ltr.management@bigpond.com

He can also do a needle bearing conversion on your stock primary gears. Dramatically improves gear and neutral selection. Also when stationary.

Includes needle, inner and thrust races, thrust washer, 3x screws/nuts and fitting instructions.

 

convert original primary gears to needle bearing

 

This too has been posted. Again interesting enough to warrant its’ own post. Something that, in all the years I’ve been playing with motors, I’ve never really considered.

 

 

285-1 … primary drive, driven gear lash tolerances

 

 

285-2 … primary gear lash tolerances