We got up early and went to the swap meet down in Long Beach, CA, last month, looking for a couple of things that none of our friends either had or would part with. As we wandered the back lot (past the grandstands) up one aisle and down the next, we seemed to be following a couple of young guys looking to buy a four-speed transmission for a Big Twin. The one guy who was going to be doing the buying would get all excited when he saw a candidate sitting in a seller's booth and would begin to rapid-fire questions at his buddy: "Whaduya think? "Do you think it's OK?" "What about that bead of weld?" Most of the time his buddy's response was "I dunno, it looks good," or "Go ahead and ask the guy what years it'll fit." We forgot exactly what year that transmission was supposed to fit, but it didn't sound right to us.
On our way home from the swap meet (empty handed) we fell asleep in the truck...no, wait, we were thinking, yeah, thinking about some things to look for when considering a used trans at a swap meet. If the seller has the top and/or the side cover off the transmission to show the gear set, so much the better. But we'll deal with looking at the outside first and go from there. The transmission we'll be examining is a real 1975 Harley-Davidson four-speed Big Twin unit. The trans belongs to Wes at Four Aces Cycle Supply in Pacoima, CA, and is part of the shop's H-D project bike. After witnessing the bike the trans came out of while researching another article, we would be completely surprised if this was a "fresh box." And not to disappoint you, it wasn't fresh, but it wasn't bad, either. There were some outward signs that all was not right; however, we were somewhat surprised by what we found inside-sloppy assembly work. The final conclusion was that we left the gears and shafts assembled and fixed what was wrong, replacing the seals in the main drive gear and the starter shaft bushings in the side cover. We also tuned up the ratchet top while we had it off the transmission case, but we'll save that story for another issue.
The '75 Harley-Davidson four-speed...
The '75 Harley-Davidson four-speed on the bench. It's been cleaned in the parts washer up at the Four Aces shop to remove the heavy mung.
1. Before cracking the box...
1. Before cracking the box open we felt it-we turned the main shaft by hand, feeling for roughness or a notchy feel that would indicate bearing or bushing problems. The main shaft felt fine, although we did notice that the transmission sprocket was loose on Fourth gear; this was an easy fix with the right socket. We didn't feel too bad, because the sprocket nut was not all buggered up with a chisel and hammer. The sprocket is toast; a couple of teeth were chipped and all the teeth are hooked. The top of the transmission case is grooved from a loose rear drive chain.
2. On the kicker side of the...
2. On the kicker side of the transmission, we unhooked the kick-starter return spring and rotated the kicker arm while watching the starter shaft. The shaft was bent.