AF close ratio 4 speed gearbox

[al pushpak]

Hi, currently running a Ts 225 ,yamaha 110 rod crank with a 2.5mm cylinder packer,BGM clubman exhaust & 30mm dellorto carb,gearing is early li 125 with 17x46 sprockets giving me a 4.99/5.0 final drive in 4th, it pulls ok with this set up but was just contemplating purchasing an AF close ratio 4 speed gearbox to maybe increase the performance & top speed,i know the BGM clubman restricts top speed as opposed to a performance pipe but I prefer the torquey set up the clubman gives.i will be interested to hear your thoughts. many thanks

[holty]

af close ratio 4 speed is a good box, its based on an indian gp200 gearbox, it uses the 3rd and 4th gear from one, the other 2 gears are closer together than the gp 200, i like these, ive just fitted one on my latest build, you get a long first gear much longer than your 125 box, then the gears are close together, great if you have a powerband, i dont suppose you will with that pipe, but you might be able to pull a lower final drive ratio as you will have a lot of torque, and the gap between gears is small, ive used a 19 front and 46 basket giving a final drive of 4.89 in top gear, yours might pull this , you may have to try it. af sells all the parts seperately as well if you break anything, ive had to replace a cluster on my rb250. the close 5 speed has i belive about the same ratios for gears 1 to 4 and has 2 options for gear 5, costs a lot more money though. all in all af 4 speed great box when you get the final drive ratio to your liking, and riding style
holty

[al pushpak]

hi Holty, thanks for your reply & info, very helpful & informative, I like the idea of the gears being close together, especially where I live as its very hilly !I'm still in two minds whether to purchase one or not, not really keen on the idea of the clusters breaking after all its a lot of money to shell out if it breaks,also will AF replace it foc if it does ? & its not a 5 minute job to change it either, will have a think , thanks again

[Watfordwhite]

Al, pretty sure the problems AF had, have now been resolved and well documented. All credit to AF for the way they handled the problem. Although I'm sure it was only the 5 speed option that had an issue.

[dickie]

Al, pretty sure the problems AF had, have now been resolved and well documented. All credit to AF for the way they handled the problem. Although I'm sure it was only the 5 speed option that had an issue.

Correct

[Warkton Tornado No.1]

There can be no doubt that with such an excellent, race inspired pedigree, that Ray Kemp has raised the game as far as those of us silly enough to meddle with Italian shopping machines go.

However, there has been issues @ time, & early close ratio 'boxes were renowned for having 'soft' loose gears by comparison with OEM gears. (IMHO, that is to be preferred to hard (therefore brittle) gears such as those personally experienced from a top Italian special gearbox manufacturer, which can break so easily. Grrrr!)

In any case, the point I would labour is that full clearance of the clutch is a 'must' as drag can test a gearbox & cause breakages, so spend the time ensuring that there is more than enough, remembering that five or six plate conversions need more. Not so long ago, even nine plate clutches were being utilised prior to the advent of better generic design clutch plates or motorcycle derived designs.

That is the reason that the angle & the length of the clutch arm need to be considered with such conversions. Think about how the angle will translate to more rotation & a shortened (cut & welded) clutch arm will also result in more angular movement if you are unsure, by sketching it out if necessary....