RGM gearset

hello Laurence

i've no real experience with it but i thought about the close ratio gears for my commando 850. i calculated the thrust ratio's for both (original and close ratio) and for road use it is better to stick to original in my opinion .

the close ratio gears thightens up 2nd 3rd and4th keeps the gap between 1st and 2nd . first becomes heavier meaning more use of the clutch.

as mentioned before this is for commando i don't know if gear ratio's are the same for the laydown box

Hi.

Probably not advisable. The AMC box (for which the RGM gears are intended) has the end of the mainshaft secured by a nut under the clutch operating mechanismon the right hand side bearing which stops the mainshaft shifting sidewayswhen the clutch is operated. The laydown boxmainshaft is not secured andrelies on a bronze thrust washer between third and fourth gear which abuts against a hardened steel washer inset into the fourth gear. This prevents the splines on the mainshaft grinding away the rollers in the laydown box's 4th gear. Without the thrust washer set up, each time the clutch is operated, it would probably eventuallyresult in the destruction of the needle rollers in the RGM 4th gear, the splines on the mainshaft and probably damagethe 4th gear as well .Without the hardened steel washer the bronze thrust washer wouldwear out pretty quick.

Someone out there may have done it with a bit of machining and a needle roller thrust washer bearing (Ken McIntosh does these) - if they have I'd like to know!

The mainshaft 1st gear would also have to be modified.

Regards,

Ian.