23 October 2016

Sunday, October 23, 2016

Yesterday I took my 5-speed A65 gearbox back to Nova Racing transmissions. They were keen to see how it had performed after a good 500 miles of operation in my 1971 Lightning.

Over the past weeks the gearbox has performed very well and the ratios are in fact better than the more common TriBSA 5-speed gearbox fitted to T140s T150/160s and the Rocket 3. The 3-4-5 spacing is better with a slightly smaller jump from 4th to 5th. This gearbox seems immune to differing oils, having tried both 75w80 and 85w90 grades – some older ‘boxes just don’t feel right with modern thinner oils – the Nova was fine.

When I first had the gearbox I was a little perturbed to discover that it was a 1-up 4-down arrangement. Fine if you are used to the earlier A10 or pre-unit single but I wasn’t! It’s bad enough having a LH change Bonneville to cope with, without having to think ‘upside down’ when out on the A65.

The good news is that this has now been ‘corrected’ with a new selector drum that works the other way round. So hopefully no more accidentally over-revving the engine! See old and new in the photograph.

I took the bike on the Hampshire BSA camp back in July and as usual my son came with me on the back. The bike worked very well, even with nearly 30stone (190kg!) on the seat and I was grateful for the very slightly lower (2.8:1 compared to 2.5:1) than standard 1st gear. Nova also offer closer ratios suitable for the track where 1st gear is 2.2:1.

The thoroughly modern selector mechanism is a drum and this makes finding false neutrals almost impossible. It is also easy to select any gear while stationary with the engine running. Sometimes it can be hard to find neutral if you have top stop quickly in 4th – no problem with the Nova.

With a few final tweaks now incorporated into the design, this beauty is now ready for production.

Re-post from FB David Drew (https://www.facebook.com/david.drew.332)




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