4 Speed Transmission Ratios

kickinon
Posts: 9
Joined: Tue Feb 15, 2011 7:09 am
Bikes: 1950 panhead
1956 panhead
1942 wla
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Re: 4 Speed Transmission Ratios

#16

Post by kickinon »

sure is relevant, its now 2020 im in here in australia, due to covid not much happening till restrictions ease,,so looking at my 1958 gear ratio's l built the trans from scratch ,l like the ratio's at the moment from what l can tell from a 15 mile trip (just finished the bike build),but 3rd has a terrible whine'y type sound,it has to be sorted, some parts like the main & counter shaft shaft cogs had use, but l replaced both shafts and all the smalls with new parts,,, googled panhead trans ratio's, & was led to this site , been a member of P&F for some years now,,l dont feel like taking the trans out just yet,
, l will ride the bike till its run-in at least,, just thought id gather some imfo on ratio's for now..



RUBONE
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Re: 4 Speed Transmission Ratios

#17

Post by RUBONE »

From 1940 to the early '70s H-D only had one set of gears/ratios for 4 speeds. In the early '70s an additional taller first gear set was installed in FX (Superglide ) models. Everything else is aftermarket.

3rd gear whine is common on all 4 speeds but tends to be worse on the models equipped with a mainshaft 3rd gear with a bronze bushing. The bearing area is narrow, it waers rapidly since 3rd is used so much, and when worn cocks slightly allowing the gear teeth to howl against each other. The 3rd gear and mating 1st-2nd cluster were changed from '59 up to create a much wider bearing surface which became steel on steel and eliminated most of the whine issues. They must be replaced as a set as mixing early and late parts does not work. A new bushing helps but ultimately it will come back although it will take a long time. And early gearboxes with factory bushing should never be run with old style sulpher based gear oil in them as the bushings are high sulpher content and slowly dissolve in the oil creating rapid wear. One reason why H-D called for motor oil in their gearboxes.

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