Gearbox internals

[oldtimer]

I have a RRT2 gearbox with the high ratio gears and was thinking of changing the internal cogs for the standard ratio. Is this possible by just changing the cogs? I want to retain the RRT2 but lowering the overall ratios.

[JulianS]

The main issue will be that the RRT2 mainshaft is not compatible with a bushed sleeve gear so you would need to change the mainshaft as well. The RRT2 mainshaft is stepped, the inner portion which fits the needle roller in the sleeve gear is about 0.002 inch larger diameter than the portion which fits the bush. This inner portion does not have an oil scroll, which the standard shaft does.

RRT2 shaft shown below.

The only pinion common to the RRT2 and STD gear cluster is the layshaft "F" gear.

[tdc]

Seems a shame to do that why not alter the drive /rear wheel gearing ? Back in the day my mate had a 350 Gold Star it would do 90 in third and 92 in top .crackin bike .Good luck .

[JulianS]

That would not alter the internal ratios which is the issue with the RRT ratios on a road bike.

[idie]

Some years ago one of the branch members had fitted a modified A65 first gear in his DBD34 to lower the first gear. Other then seeing the gear once I don't know what was done to it.

[oldtimer]

Think I have it sust?. Going to swap the main shaft first gear pinions and third gear pinions from the STD box. I have to change the third gear pinions as the RRT2 pinions will not engage into the first gear pinion, there will be a slight lowering of the third gear but that will not affect my style of riding. Just have to press the pinions off the main shaft.

[idie]

That sounds like a good answer. Let us know how it works out.

[oldtimer]

To save a complete STD box I am looking for the first and third gear pinions from a STD BSA swinging arm gearbox.                         
    E,  G, H & F . [E = 24  G= 16 mainshaft] [ H = 27 & F = 19 layshaft] and no I have not lost them down the road.             
        If anyone has these pinions going spare please contact me.

[oldtimer]

All sorted now. I now have a complete STD gearbox. I do however want an inner gearbox case as the one I have has a broken clutch cable terminal, half of it is missing. So if anyone has one going spare and would like to sell it [at a reasonable price] please let me know. Thanks