Pacemaker gearbox cluster size -later type

[al pushpak]

Hi, does anyone have to hand the measurement of the 3rd gear cog on the cluster/Xmas tree on the later ,stronger pacemaker gearbox, I have the later 3rd gear loose cog (33.8) but not sure about the cluster many thanks

[Danbretta]

I'll have a look tomorrow morning for you as I'm putting mine back together. Unless someone comes back to you sooner.

[al pushpak]

Nice one! if mines the wrong type you don't have a spare one to sell do you!!? cheers

[Danbretta]

I think both early and late used the same clusters. 11 13 17 19 teeth.

[Danbretta]

No sorry, the only one I have is what was in the engine. I have an early pacemaker but looks like the later 3rd gear was put in some time along it's life. (Unless it was in from new, don't know how accurate the records are)

[al pushpak]

No worries I think I may have the early type cluster & I definitely have the later stronger 3rd gear, just can't find any dimensions or measurements anywhere regarding the cluster thanks again

[Danbretta]

https://www.mbdevelopments.co.uk/lambretta/lt7.html

[Warkton Tornado No.1]

No worries I think I may have the early type cluster & I definitely have the later stronger 3rd gear, just can't find any dimensions or measurements anywhere regarding the cluster thanks again

To my knowledge, there is no difference in the cluster third gear teeth size of early & late Pacemaker 'boxes, but I stand to be corrected.

When they fail, as the early third loose gears tend to, it will only be the teeth of that individual gear that will strip, in my own experience. If proof were needed, I have utilised a Pacemaker ' box in race & road tuned engines for years that has the centre bored cluster as my belief is that enables the best OEM type clutch components to be fitted with the centre spindle, rather than the later type which can tip @ an angle, making component clearance variable.

All Lambretta gearboxes are based upon a modular design but are 'bastard' gears to achieve the desired ratios.

Therefore, what Innocenti did to strengthen the fragile loose third gear, was to marginally increase the thickness of the teeth to gain strength by modifying the actual PCD of the gear. Taffspeed took this principle to to the extreme by producing their close ratio gearboxes which meshed special (even more bastard) cluster gears with standard OEM loose gears to produce a very strong product. Despite what you may read elsewhere (from somebody that may claim to have invented the wheel.....) they did work very well, as I believe I bought the last two sets from Ian, & they proved bullet proof.....