Gearing for 2 up

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Dec 24, 2003
With the 21 tooth gearbox Sprocket and 170 kgs in weight for my wife & I, the Norton would be better off with the 19 tooth sprocket I reckon.

The extra zip would be good off the mark and through the twisties going up hill. The 19 tooth would help here BUT...

Is there then an easy way to change the 4th gear ratio so that you have relaxed highway cruising and have the motor reving like it had the 21 tooth sprocket ??

Thanks in advance for any ideas/solutions to my question :D
I don't think you can have your cake and eat it too. There are close-ratio gearsets and five-speed gearsets (Quaife), but top gear in all is still 1:1. In fact low gear in the Quaife is higher than stock. No gain there.

I have a 19 tooth sprocket on my 750 Roadster, a 22 on my 850 Interstate, and a 21 on my 850 cafe racer. The 19 is too low for anything other than zipping around. The 21 loses very little with the hot-rod 850 motor. But the sweetest is the 22 on the Interstate. Loses a bit of bottom acceleration, but the near stock 850 pulls good mid-range and will cruise 70-80 mph with ease.

Ron L
the 4th gear is one to one. the input is locked to the output and NO way to change it. the other complaint is that nobody offers a 5 speed with a lower 1st gear either. next is a 19 tooth is to low for much over 65 mph cruseing. my bike with a 19 is running 4700 rpm at 70 mph so I will NOT run over that for ANY distance. one thing you could look at but you would only have three normal gears would to make third an overdrive than use 4th as 3rd but it would have a very big step from 2nd to the old 4th.

Changing Gears

If you look in the RGM 2004 Spares Catalogue on Page 4, Item 138A, Part No WL417 is a 17 teeth Layshaft fourth gear for 31.73 pounds.
Now the "normal" layshaft fourth gear is 19 teeth.....

So come on you math geniuses, help !!!, tell us what will happen with 4th gear if you put in a 17 teether.

Or just to try and confuse you all, what will happen if I put in Item 137B, Part No WM425, which is a 25 teeth Main gear ? (Factory is 23)

My guess is, if I replace the current 19 tooth gear layshaft with the 17 tooth layshaft gear, I will have more relaxed cruising in top.

If this is true & I put a 19 tooth gearbox sprocket on....I can have quicker acceraltion(more grunt off the mark) and usefullness thru twisty mountainous roads, yet not be over revving in top gear on highway speed limits ?

Please advise.....??
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