Disappointing RB20.

[lozmondo]

4.80 seems tall gearing for a revvy kit ?..I had similar on a TS, dropped a tooth and it transformed it

[10 inch Terror]

4.80 seems tall gearing for a revvy kit ?..I had similar on a TS, dropped a tooth and it transformed it

It's the final drive recommended by AF for a 12 stone rider. I'm 16 stone I don't think I know any scooter rider below 15 stone . I remember the NK is the mid version and not the Rally. Like I said I'm going to split the casing and see what's what.

[James]

Mine was gearing and pipe issues that made it hard work to ride, I originally had the Spanish LI150 gearbox and NK race pipe, awesome powerband around 6-7,000 revs but nothing lower down, the gap between 3rd and 4th was huge and it was awful to ride. I spoke to Ben at AF and he changed the gearbox to the AF close ratio, swapped the pipe for the midrange, put a long stroke crank and had the barrel ported and matched taking it to a 212cc. Quite a few mods I know but completely changed the characteristics, much easier to ride now better power spread throughout the range, close ratio box has a really long 1st gear so need a little slipping to get going but couldn't be happier now, still running the 34mm carb was does spit a load of fuel so may reduce to the 30mm put apart from that all good, goes like a rocket and can still ride around town.

[Adam_Winstone]

4.80 seems tall gearing for a revvy kit ?..I had similar on a TS, dropped a tooth and it transformed it

^... LIKE

[Norrie Bodge]

I built the motor 2 years ago and I'm pretty sure I used a 17/47 sprocket combo. I know I was aiming for AF's recommended final drive of 4.8. To be totally honest I'm doubting myself now. I think I'll whip the side casing off today and check exactly what's in there. If I jet the carb exactly to AF's recommendation and ensure the gearing is correct and useable the only thing left will be the pipe. Cheers guys I'll report back later.

Me mate says he was having to thrash its head in in 3rd to get the revs up to keep goin when in 4th?
says now goes great with 15x46

[Eibar]

had rb20 with nk mid range runnin on 34 vhsb - mucked about loads with gear combos an ended up gp200 close ratio but runnin a final drive ratio of 5.6 at the end of the day its a hooligan kit and needs to rev like chainsaw.

[10 inch Terror]

I'm thinking of fitting an NK Race and going 15/46 on my Pacemaker box. This gives a final drive of 5.64. The Race should give me the revs I need? Any thoughts on this please?

[corrado]

I'm thinking of fitting an NK Race and going 15/46 on my Pacemaker box. This gives a final drive of 5.64. The Race should give me the revs I need? Any thoughts on this please?

It'll absolutely fly [if carburation is good] and will lift front end in 1st, 2nd and 3rd.

My RB 20 has been slightly tuned [24bhp] with PHBH30 and Franspeed race. I can't remember the gearing, was aiming for 5.00 but couldn't get that so think it might be 5.1 [18 x 46 on GP200 or 4.95 with 19 x 47]. It takes off at 5,000 rpm all the way to 8,500, over 80 mph. I'm only 10 stone though. Wanting to try a TMX35 to see if I can get it to 90mph on the 1/2 mile strip, currently 84.

[10 inch Terror]

I've split the casing and it's running on 17 / 47 as I suspected. Now I have a new 15 tooth sprocket and suitable chain but the clutch is a brand new LTH and @ almost £400 I don't really want to buy a new one. Does anyone know if you can buy the LTH sprocket on its own?

[corrado]

I've split the casing and it's running on 17 / 47 as I suspected. Now I have a new 15 tooth sprocket and suitable chain but the clutch is a brand new LTH and @ almost £400 I don't really want to buy a new one. Does anyone know if you can buy the LTH sprocket on its own?

Yes ..... if they ever ever have any in stock. Great clutch, got one in my Mugello, not touched it in about 4 years since fitting it. Got AF 6 plate road in my RB, also no issues and been ragged up the drag strip about 30 times.