Rapido 225-Correct Gear ratio

[mikeallen]

Hi All,

I'm currently running the following set up on my series 3 Li & while I've put up with it for most of this year & done a fair few miles I'm starting to wonder if I have the gearbox selection wrong or maybe something else is amiss maybe

Rapido classic 225, 30mm PHBH on Breath sweet filter, JL3 exhaust, SX200 gearbox 46/15 @ 4.80 final drive, Timing strobed at 17 degs BTDC, Squish set at 1.5mm.
Carb jetting: 120 main, AV266 with X7 clip 2, 300 float valve, 52 pilot, 70 choke.

Basically it pulls great in 1st, 2nd & 3rd no problem even 2up but 4th gear on any slight incline drops out of the power very quickly & then find myself ragging it's tits off in third to keep it in the power band only to drop into 4th again to feel a little flat & not much power at all so back into 3rd it goes. If 4th gear pulled as good as third then the scoot would i'm sure be more fun to ride rather than slogging it between the gears as soon as it hits any incline on the road

Is it a case that the gearing is just too tall at 4.80 for the hilly roads round my way & 2up riding or the selection of the SX200 gearbox incorrect


Any advice would be much appreciated or would be interested in hearing what other gearing setups are out there for the Rapido

Mike

[skidmark]

I am running pretty much the same set up except mines is a 200 Race Rapido, I have been running this for a good few years now and have tried many gearbox/sprocket combinations, I also found the SX 200 box on 15/46 (4.8) pretty useless, I also had this set up in a 250 Rapido for a while and it wasn't much better, my 200 Race Rapido likes to rev so I now run an Italian Li 150 box on 15/46 sprockets (5.2) and have found this to work very well and the 250 now runs an Italian Li 150 box on 16/47 (5.0) and this also works well, maybe not the fastest set up but much easier to ride without the changing up and down the box every 2 minutes!

[Dimitrios_231]

The correct gear ratio,
depends on the type of gearbox and exhaust used.

If it can't pull 4th,
either change gearbox to 5.0 or higher number,or fit a pipe (usually clubman style) that will have more power lower down.

JL3,(I've used only the curly version),does't give much power low down,compared to Clubmans.
Standard SX 200 gearbox usually works very well with classic Rapido kits,fitted with clubmans and PHBH carbs.

[goldeneye]

rapido 225 classic, 30mm solid mount dellorto, remote filter. indian GP 200 gearbox, 19/46 cogs (4.8) pulls great , even 2"s up, with a 42 mm AF clubman. tried a couple of other pipes, but went back to the clubby. when we go away, i"m 2"s up a lot of the time, so i need grunt more than top speed, and the clubman works. in fact, i"m gonna buy a new style one for me GP.

[mikeallen]

Thanks for the repiles much appreciated

Looking to keep the JL3 on the scoot rather than a clubman exhaust so fitting an Li150 Gearbox 16/47 should be a good option then

I already have the sprockets & chains to give either 5.2 or 5.0 on the Li150 box so will give it a go

Mike

[soosh]

Mate,you sure you have a classic kit? With a JL3 it should eat 4.8.Something is not right,you sure timing is correct and carb? I run an iron kit and used a JL3 curly with a 28 and it pulled so well,i even thought of going 4.6 and thats only a 200cc kit so thats why i think something is not right with yours or maybe its the race version.

[mikeallen]

Mate,you sure you have a classic kit? With a JL3 it should eat 4.8.Something is not right,you sure timing is correct and carb? I run an iron kit and used a JL3 curly with a 28 and it pulled so well,i even thought of going 4.6 and thats only a 200cc kit so thats why i think something is not right with yours or maybe its the race version.

Yes classic 225 with full skirt asso piston. Timing strobed at 17degs & don't think carb settings are miles out as plug colour after plug chops are fine. Just wished it pulled in 4th like it does in 3rd

[soosh]

Full skirt piston.I take it thats just what it comes with and is deff the correct one for the kit.Maybe speak to AF as its their kit and their spec but you should easily pull that ratio,try that first before dropping to 5.2.

[tobytyke]

Got the same set up as yours...i phoned and asked about the the engine settings...19 degrees is what i was told the timing should be set at...if that helps.

[Eibar]

carburration is about right, mirrors mine but I use a 118 main (got more power than with a 122 and Air fuel is at 11.99).

I use 4.8 currently but this does struggle on the big hills of wales and scotland but I can live with this. It even struggled on hills with 5.0 ratio in extreme weather but so did my mates TS1. IMHO 5.2 is too revvy to get best use from a classic rapido unless 2 up all the time.