So I spent a bit of time on the weekend doing the gearing change I mentioned in my previous thread. Changing the rear sprocket from a 41 down to a 38 tooth.
First I had to machine out the centre of the 38 tooth blank to suit the N400 sprocket carrier:
Then I had to drill the holes for the sprocket bolts using the OEM sprocket as a template. I also drilled some larger lightening holes as well:
After a bit of elbow work with some scotch brite to polish it up a bit I fitted it to the sprocket carrier and then the wheel:
I was pleased to find after tensioning the chain that the rear axle had only moved half an inch further back in the slot from where it was before. So I still have considerable adjustment left before I need to start taking links out of the chain and fitting a joining link. I don't want to butcher the OEM endless chain before it's worn out.
Out on the road first gear is now much more usable and you can get a decent amount of momentum on before you start reaching for 2nd. Through the gears the ratios still feel close enough for my liking and there's no big holes there but sure, its maybe not going to do quite the same 0-60MPH time as before but there wouldn't be much in it and I'm not bothered.
What is good is the more relaxed cruising in top gear. 5,500RPM at 100kph / 60 mph.
At 7K RPM I'm now doing 128kph / 80mph. So much better for sustained high speed runs.
It feels like you could get away with dropping another tooth yet to 37 but then perhaps you would start to notice the wider ratios and first gear may require a little more slip of the clutch to get going.
So I'm really happy with the bikes gearing now but one thing I did confirm is that the speedo does not run off the transmission (as it did on my CBR) so I have not corrected the speedo error.
Cant have every thing in a modification eh. :grin: