It is quiet today on the Forum so a question.
Do any of you run a 5 speed cluster in an A65? I have always found the gap between 2nd and 3rd a bit big especially when going up long hills. 2nd to low and revvy and 3rd to high and hard on the engine. Going down hill it is fine.
Dave.
I should add that I run a 21 tooth gear box sprocket which is great on most roads. I suppose to widen the discussion A10s and Gold Stars should be included as they can have 6 gears if you want them.
Dave.
A bit of a twist on gear ratios that could improve things. Surfing the Britbike Forum I came across a thread asking the same questions about gear ratios. A solution worth trying is to use the second gear pinions from a close ratio box and put them in place of third gear in the standard box. This effectively lowers third to give a slightly bigger step to fourth and close the gap between second and third. Has anyone tried this?
I have just had a rummage through a box of pinions and I think I have found a close ratio set. It is not easy when there are no part number on the gears and the tooth profiles vary as well.
Hopefully I will give this idea a try at some point in the future.
Dave.
would a 5 speed box be a problem? is there room in the case for the extra pair of gears. Quaife would be the people to ask.
https://www.quaife.co.uk/quaife-products/motorcycle-gearkits/
asfor the gears ratio, a good engineer should be able to check them through, Ive got tangent mics and pins as I used to cut them years ago then its work out DP's, Adendums, dedendums and other info needed then a old style engineering workshop could cut them if they have the hobs
Hi,
There are currently two options available. One by Nova Racing that is based on the Triumph ratios. They look ideal with a lower first gear and fairly even spacing up to fifth. This looks like a good option for road use but very expensive at over £3000. The other is by PES and while far more affordable at £2100, the ratios are more racing focused with a higher first than standard and fourth being even closer to fifth than currently third is to fourth.
I am going to ask PES if they can make a more suitable set of ratios for road use.
The idea of using the BSA close ratio second gear to replace standard third is obviously a cheaper option to get a slightly wider gap between third and fourth in a standard box.
From what I read on the Britbike Forum it makes a favourable difference.
Dave.
Hi all,does any one possess a quaife 5 speed gear box as i would like to borrow the camplate in order that i may copy it.Thanks
The Nova box came about because I was after a Quaife box at the time and Quaife weren't interested unless I could sell 20, I had about 6 definite orders but that included 2 for my own. The ratios were and still are terrible. A huge gap between first and second, 3 close gears and a huge gap between 4th and top. First was still fairly high so for racing you'd have wanted a 19:47 with standard clutch ratio for first to work, otherwise you'd be left behind at the first turn. Quaife didn't want to alter the ratios so I moved forward.
Nova had been approached by this point but they weren't prepared to do the work without some money thrown in. This isn't the kind of thing I have lying around. Some time later another BSA Member approached me and offered to go forward with the project, they put forward the money and spoke directly with Nova, I did some work on the Ratios.
Two ratio sets were intended (and I believed carried forward) close ratio and a standard road set. I worked the ratios out against my own bike, calculating the drop between the gears, if revved out to the max and then putting the bike about 1/4 way into the power band. The road set was a little wider.
It's not as easy as it sounds as there's a lot of back and forth. BSA used a different gear pitch on the close ratio gears I believe (if you compare the teeth numbers of other gears then look at the size of the close ratio gears they are smaller with same or more teeth. No box supplier wants to use a different tooth cutter as this costs more in setup time so I had to keep readjusting to get them all to fit as evenly spaced as possible. There was then a lot of different measurements taken from different years of crank cases as they were not all the same. For example a pre 70 cam plate won't fit a post 70 case without some adjustments to the case. Nova eventually came back with ratios which were as close as possible and worked within their process.
None of the boxes were based on the triumph though, although the triumph ratios were looked at for comparison.
John Hill was designing the PES box at the same time and it came out first at a much better price.
And after all that I still didn't end up with a 5 speed box....