No. 50 Flywheel Rebuilding Fixture
Our No. 50 Flywheel Rebuilding Fixture is an absolute necessity for rebuilding any pre- twin cam flywheel set. It will make your life a whole lot easier. Buy once, cry once.
- Enables easy disassembly of old flywheels for rebuilding
- Allows you to hold the flywheel and accurately torque the pinion shaft, sprocket shaft, and crank pin nuts.
- Billet design means tighter tolerances for a more consistent product
- Hard anodize finish means it will take all the abuse you throw at it
Product Info
- 6061-T6 aluminum with hard anodize finish
- Fits all H-D and aftermarket flywheels that have either tapered shafts or a tapered crank pin.
- 100% made in USA
How to use
There is A LOT to flywheel rebuilding. This is only a simple overview.
Flywheel Disassembly
- Place Flywheel Fixture in vise, mounted to sturdy table
- Place flywheel assembly in fixture
- Remove crank pin keeper screws and keepers
- Loosen crank pin nut
- Flip flywheel assembly over and do the same to the other side
- Use steel wedges to spread flywheels and break bond between crank pin and flywheel halves
- Remove rods, bearings, and crank pin
- Place individual flywheel half in the jig, remove shaft nut keeper and shaft nut. Tap shaft out with rawhide mallet or other soft hammer.
- Repeat for other flywheel half.
Rebuilding process:
- Replace worn parts
- Rebalance flywheel halves for new rod & piston weights
- Reassemble flywheels
Flywheel Assembly (simple overview only):
- Ensure all tapers are clean and dry. Wipe everything with acetone
- Use jig to assemble shafts back into flywheels by torquing nuts to specification
- True pinion shaft to right side flywheel. Check runout of side of the flywheel with the both ends of the center shaft mounted on centers. It's very important that you are able to achieve a runout of less that 0.001". This may require persuading the shaft a bit in a particular direction. You can use a sacrificial pinion nut on the shaft in order to protect it during this process. Repeat this until shaft is true to the flywheel half.
- Repeat with sprocket shaft and left flywheel.
- Install keepers on pinion shaft nut and sprocket shaft nut
- Place RH flywheel in shaft-down orientation on the fixture.
- Install crank pin and key, and snug crank pin nut hand-tight
- Install rod bearings and rods. (forked rod is the rear rod, so if facing the notched side of the jig, this rod should be on your left).
- Place the sprocket shaft flywheel on top of the crank pin
- Use two pieces of steel C-Channel and 1/2-20 all-thread rod to clamp flywheels straight. We like to use 4" wide C-channel (7.25 lbs per foot). Each piece should be cut approximately 4.75" long, and have a hole drilled in the center for the 1/2-20 all thread. Tighten with nuts and washers onto flywheel assembly.
- Snug crank pin nut hand tight
- Flip over flywheel assembly and alternate tightening crank pin nut on each side until final spec is achieved.
- Don't attempt to true flywheels until crank pin is fully tight. You're just wasting your time, because it will go out of whack every time you tighten the crank pin nuts.
- Make sure endplay of rear rod to flywheel thrust washers is acceptable. Anywhere between .010 and .050 is acceptable in our opinion.
- True flywheel assembly. This is a whole other adventure. And the old school outlook is that you only have 15-20 minutes to true a set of flywheels, if using green loctite on the tapers. We like to use a couple drops of Loctite 609 on all the tapers.
- Install crank pin nut keepers
- Install plug in the end of side-oiling pinion shaft, if applicable.
- Build the rest of that motor!
There are a lot of ways to skin a cat!! There are a ton of different ways to do things, and there is no single correct way. People have very strong opinions on how to rebuild flywheels. This is only a simple overview, and expresses our opinions only.