Scooterotica

Hi all,

just opened up by Challenger 240 engine, as need to replace Drive side Oil seal.

Want to change gearing, as does not really pull 4th well. Seem to remember from last time was SX200 gearbox. Stupid me should have actually written teeth number down etc.

Anyway its got an LI 150 gearbox, running 47 x 18 sprockets, 82 chain. According to Sticky's book, that looks to give a final drive of 4.8

Bike goes great in all gears except fourth, was following a Vethpa 300, he said a steady 80 85, and I was still in 3rd, going up a slight gradient, could not pull 4th.

So whilst got it apart want to change setup.
I have SX200, Pacemaker gears, and various sprockets to play with.

so again looking at Sticky's book, guess will go for a final drive of about 5.0. Sticky's book does not seem to show sprockets for pacemaker. What are suggested sprockets for pacemaker in this setup ?

So what is everyone's thoughts ?

I don't have an 81 link chain, but happy to go that route.

All advice accepted.

Martin

Pacemaker with 46/17 will give 5.0 GR

lol if u hav a lammy that dos 85 in third y even bother with 4th gear !!! ud bee doing over a ton !!!

Li150 16x47 with 81 link chain = 5.0 and is a nice gearbox on TS1 with Devtour, but it won't do 80mph in 3rd however you don't say which exhaust you're using.

Hi all, thanks for responses.

Ok here is set up...... Challeneger 240 (as worked 25 years ago by Martin from Chiselspeed and Bob Monkhouse.

Kawasaki 750 piston (about 3 months old), cutout matched to ports via Martin at Chiselspeed.

Tons of low down grunt, vibrates the hell on tickover, but really smooth when running

Massive transfer ports, loads of weld on case and barrel.

Reed valve induction on normal side, via an old MBD manifold, with Mikuni 35.

Currently running JL4 race. (have a few other exhausts to swap and play with later).

Sorry for delay in responding, just been in garage playing. Put pacemaker in and for the hell of me could not get gearbox end plate back on. Evetually worked it out that 3rd gear was pushing too hard against Xmas tree.
Luckily I have another pacemaker, swapped 3 gears, and hey ho its works. I obviously have a rogue 3rd gear in one of my boxes (the wider type 3rd, which I thought was from the later box, will check up.

Thanks for advice, will update with any progress

Martin

just been checking through Sticky's book.

using the LI150 box, with 47 and 18 sprockets, actually gives a final drive ration of just over 4.4, which would explain why I could not use 4th !!!!!!

Have added Pacemaker, so will leave in, and use original sprockets, which give final drive of 4.8, will see how I get on with that.

Martin