PK80 Gearing?

[hank]

got a PK80 engine for my next project - my sons 16 in 3 years time, thats the deadline! Anyone have a clue what the stock gearing is? similar to a 90 or maybe the same as a PK50?

Very little info online, the only stuff i could find was this in german:

www.vespa-archiv.de/80/PK80S.htm

Can't equate the bit about the gearing with other vespa's. Any clues? DOnt want to go mad with the tuning on this one, but he will need to keep up with the unrestricted twist and go's!

[Juan]

I've never had an 80 so I don't know what the final drive ratio would be but I expect it's slightly lower than the other larger PK's.There's no way it's as low as 50's though,they're ridiculously short.

What I can tell you is that the gearbox itself shares cogs with 90's and other PK models.

[guy160]

Ive had one...breifly.
No idea what the ratio is, but its more like the 100 box. Nothing like the 50 at all.

[ozoap]

Here is a list of primary drives of Et3.ie



DD=denti straight DE=denti helicoidal CP with parastrappi SP without parastrappi AC=acciaio TO = the aluminum

14/69 4,93 DE SP AC - Piaggio (Rush 3 m, HP)
15/69 4,60 DE SP AC - Piaggio (PK 50 4 m)
16/69 4.31 DE SP AC - pinion Pinasco + bell originates them Piaggio from 69 teeth (sees over)
16/68 4,25 DE SP AC - Piaggio (50 N 3m)
18/67 3,72 DE SP AC - Piaggio (Vespa 50 3m wheels 9 ") Olimpia, Cif, RMS
18/67 3,72 DE SP TO - the Newfren
18/67 3,72 DD SP TO - the Newfren
21/76 3,62 DD SP AC - Cif for Vespa HP, V
18/65 3,61 DD SP TO - the Polini for Rush 3 m
22/72 3,27 DD? P AC - Rush 3 m
24/72 3,00 DD CP AC - Olympia, Cif, RMS
24/72 3,00 DD SP TO - the Pinasco, Newfren
21/62 2,95 DD SP TO - the Polini
22/63 2,86 DE CP AC - Piaggio (VESPA 90 NORMAL SCHOOL), Olympia, Cif, RMS
22/63 2,86 DE SP AC - Cif for Vespa HP, V
22/63 2,86 DE SP TO - the Newfren
22/61 2,77 DE? P AC
26/69 2,65 DD CP AC - Pinion DRT + bell 27/69
23/60 2.61 DD SP TO - the Polini
27/69 2,56 DD CP AC - Olympia, Cif, RMS, Pinasco
27/69 2,56 DD SP TO - the Pinasco Newfren
24/61 2,54 DE CP AC - Piaggio (ET3, 90SS, PK 125), Olympia, Cif, RMS
24/61 2,54 DE SP AC - Piaggio (Vespa PK 125 V)
24/61 2,54 DE SP TO - the Newfren, Pinasco
28/69 2,46 DD CP AC - Pinion DRT + bell 27/69
28/68 2,43 DD CP AC - Pinion DRT + bell 29/68
24/58 2,42 DD SP TO - the Polini
25/59 2,36 DE CP AC - Olympia
29/68 2,34 DD CP AC - Olympia, Cif, RMS
29/68 2,34 DD SP TO - the Pinasco, Newfren

[Juan]

;D

[hank]

you mean you can't understand oz's gear ratios either? ;D

[hank]

Eventually, after asking on numerous forums, i have found the answer (in the german PX/PK manual):

PK80 1st, 16.61 2nd, 11.05 3rd, 7.96 4th, 5.99

not much different from 125 gearing

PK125 1st, 14.74 2nd, 9.80 3rd, 7.06 4th, 5.31

ouch!

PK50 1st, 26.68 2nd, 17.74 3rd, 12.78 4th, 9.62

in fact the PK80 gearing's almost identical to the PX125 gearing, if anyones interested.

PX125 1st, 16.43 2nd, 10.99 3rd, 7.60 4th, 5.83