Tail Gunner here. This month I decided to give the old ’03 Softail a little more top end. After extensive research, I decided the most economical way to go was just swap out the transmission pulley. The stock final drive ratio for my 2003 FLSTC is 32/70 (32-tooth primary pulley) and 70-tooth rear belt pulley.
For years I wished for a sixth gear, so when Harley came out with their six-speed transmission, I knew it was time for an upgrade. By changing out the primary pulley from a 32-tooth to a 34-tooth, you change the final drive ratio from 3.37:1 to approx. 2.95:1. In simple terms, you’re dropping your RPMs approximately 240 at 60MPH.
Now this might not seem like a lot, but believe me, it made a huge difference at freeway cruising speeds. The bike no longer over-revved at 75-80 mph, it just pops right up there, and has plenty left to give when I need it. You’ll need a few items before you get started. The Pulley (34-tooth) I ordered from JP Cycles. You’ll also need a “Main shaft Sprocket Pulley Locknut Tool” (1 7/8-inch EBay motors or JIMS), a 1 3/16-inch socket and a 1 ½-inch socket.
Also, a primary side gasket set. I spent a grand total of $251.99 for everything, way less than a six-speed transmission. Don’t get me wrong, I’d love to install a sharp six speed transmission, just can’t justify the cost right now, so this mod is next best thing.
Let’s get to it, it’s really not as bad as it sounds, you’ll need to remove the floorboard and mount, and the shift linkage. Drain the primary oil, and remove the outer primary cover.
Remove the OEM gasket, loosen the primary chain tensioner, and let it drop all the way down. Remove the clutch adjusting plate snap ring, and pull the plate out.
Then remove the rod that runs through the transmission to the clutch throw-out bearing. Now use the 1 ½-inch socket on the compensator nut (FWD) and the 1 3/16-inch socket on the clutch basket nut. I used an air impact gun at 110psi shop air. The compensator nut is right hand thread, the clutch basket nut has left hand threads. Use the impact gun on both and they spin right off.
Now you can remove the compensator, primary chain and clutch all at once, just slide them off.
Next use a 5/16-inch wrench and remove the starter motor Jackshaft and plate; the plate has a lock tab you’ll have to bend to loosen the 5/16-inch nut. Pull the jackshaft out carefully and set aside. Make sure you disconnected the battery, prior to this operation.
At this point, remove the two starter motor screws. The motor will sit in place if you’re careful, so you don’t need to remove it all the way. Now, bend the lock tabs on the eight bolts that hold the inner primary case, and remove the bolts and case.
You can leave the stator in place; the inner case slides right over it so there’s no need to remove it. Bingo, you are now at the transmission pulley. Remove the two screws and lock nut plate on the pulley, and use your main shaft sprocket pulley locknut tool and remove the pulley nut using the air impact, remember, left hand threads. Now loosen the rear wheel axle and run the axle adjusting screws all the way loose. This will give you enough slack in the belt so you can slip it of the drive pulley. This mod will also allow you to use the stock belt. Install the new 34-tooth pulley and reassemble in reverse, nothing to it!
–Tail Gunner out, till next time!!
Resources:
Primary 34-tooth Pulley– JP Cycles P/N 601-384 $126.99
Primary Gasket kit– JP Cycles P/N 610-119 $64.99
Total Investment: $251.97
