Gearing Question - Pacemaker Gearbox v SX150 gearbox

[Barry Smyth]

Hi All,

With the help of the MB Developments "guide to Lambretta gearboxes" i have now worked out that the gearbox that came in my "box of engine parts" from a S3 Li150 is indeed either a late S3 Li125, Li150 Special or a Pacemaker Gearbox.

1st - 50
2nd - 41
3rd - 39
4th - 35

Cluster is
1st - 10
2nd - 12
3rd - 15
4th - 19

I am putting in an MB195 kit with a new crank, AF 6 Plate Clutch, 28mm carb & Devtour chamber, my question is should I can this along with the SX gearbox & look for a S3 Li150 gearbox? Will this gearbox work well with the kit outlined here?

[sydduckett]

Hi All,

With the help of the MB Developments "guide to Lambretta gearboxes" i have now worked out that the gearbox that came in my "box of engine parts" from a S3 Li150 is indeed either a late S3 Li125, Li150 Special or a Pacemaker Gearbox.

1st - 50
2nd - 41
3rd - 39
4th - 35

Cluster is
1st - 10
2nd - 12
3rd - 15
4th - 19

I am putting in an MB195 kit with a new crank, AF 6 Plate Clutch, 28mm carb & Devtour chamber, my question is should I can this along with the SX gearbox & look for a S3 Li150 gearbox? Will this gearbox work well with the kit outlined here?

Im not sure but id be happy to swap my gp200 box for byr pacemaker with maybe a cash adjustment...

[Skar]

I'd stick with the pacemaker and change the front sprocket to a 16, I run this in an Imola and it pulls like a train (5.3), I'm guessing the MB kit is torquier so perhaps even a 17 sprocket (4.98). Never used an SX150 box but understand that the 3rd to 4th jump is on the large side. Li 150 Boxes aren't cheap and I'm not sure what you would gain over the pacemaker tbh (5.21)

Having said all that, i think that you may need to recount the teeth, the loose gear is right for a pacemaker but the cluster only matches an SX150??? Unless (which is possible) that I've had one glass of red too many already...