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Early LI125 gearbox sprocket set up in a standard GP150 lump
Posted: Tue Oct 18, 2011 1:30 am
by scooterslag
Just building up another engine and I'm going to use a early LI125 box ( better option than the SX/GP 150 box's I've got) what would be the best sprocket set up for it? don't like the standard gearing on a SX/GP 150 lump, way too revy IMO. I'm sure people will say ' oh use this instead blah blah' but can't afford it at the mo and I know the early LI125 box has its uses. cheers Paul
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Tue Oct 18, 2011 6:48 am
by joespeed
just fit it and try standard sprockets 15 x 46.very short first gear ok for two up shopping round a hilly town center!
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Tue Oct 18, 2011 12:07 pm
by scooterslag
joespeed wrote:just fit it and try standard sprockets 15 x 46.very short first gear ok for two up shopping round a hilly town center!
Hahaha, ideal for the hilly part of Devon I live in, want it to be a bit smoother as well so maybe a 47x 16 or would that be too much for a 150?
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Tue Oct 18, 2011 3:25 pm
by sideout
But the SX/GP 150 is designed to be revvy. That's why they put that gearbox in it. You might find it's down on performance if you move away from a 1:5.6 final ratio.
Once you get used to the gap between 3rd and 4th it's ok on a standard set up.
I use the early Li125 gearboxes on Mugello 186s with a clubman and a 17 front sprocket to give ~1:5.
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Wed Oct 19, 2011 1:09 am
by scooterslag
sideout wrote:But the SX/GP 150 is designed to be revvy. That's why they put that gearbox in it. You might find it's down on performance if you move away from a 1:5.6 final ratio.
Once you get used to the gap between 3rd and 4th it's ok on a standard set up.
I use the early Li125 gearboxes on Mugello 186s with a clubman and a 17 front sprocket to give ~1:5.
Yeah I know chap, been riding SX/GP150's for years, yep the 3rd to 4th is a pain, especially up hill, going to swap over to the LI box with standard 15x46 set up
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Wed Oct 19, 2011 12:14 pm
by Stinky Finga
li125 box and 17/46 sprockets works crackin on the muggy 186
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Wed Oct 19, 2011 12:17 pm
by Toddy
Stinky Finga wrote:li125 box and 17/46 sprockets works crackin on the muggy 186
^agreed^

Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Wed Oct 19, 2011 12:55 pm
by sideout
Stinky Finga wrote:li125 box and 17/46 sprockets works crackin on the muggy 186
Dead right! .... when fitted with a clubman

Standard GP200 gearing with a JL3
scooterslag wrote: Yeah I know chap, been riding SX/GP150's for years, yep the 3rd to 4th is a pain, especially up hill, going to swap over to the LI box with standard 15x46 set up
Ideal! Just swap out the SX box for the Li125, then it will still be in the power in 4th as they have the same final ratios

Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Thu Oct 20, 2011 1:03 am
by scooterslag
sideout wrote:Stinky Finga wrote:li125 box and 17/46 sprockets works crackin on the muggy 186
Dead right! .... when fitted with a clubman

Standard GP200 gearing with a JL3
scooterslag wrote: Yeah I know chap, been riding SX/GP150's for years, yep the 3rd to 4th is a pain, especially up hill, going to swap over to the LI box with standard 15x46 set up
Ideal! Just swap out the SX box for the Li125, then it will still be in the power in 4th as they have the same final ratios

Indeedy

hopefully the closer gap between 3rd and 4th should help with the hilly bits of my county

cheers again Paul
Re: Early LI125 gearbox sprocket set up in a standard GP150
Posted: Thu Oct 20, 2011 9:46 am
by soullad
sideout wrote:I use the early Li125 gearboxes on Mugello 186s with a clubman and a 17 front sprocket to give ~1:5.
Good call.
these boxes are well made, relatively cheap and often had little use / wear.
Using this larger front sprocket to get the desired gearing is a preferred way, rather than fitting a different box, it helps with reducing stress on the clutch (think GP 18 x 47 to give 5.2 to cope with the inc. hp output), and this plus the short first gear ratio can only add to improved clutch life / general engine wear. Can also a new 81 link chain.