Crankshaft removal & installation

Crankshaft removal & installation

Watch the walkthrough

Watch on YouTube ↗ · JETSURF Service Tutorials #11. Timestamps in the steps below follow the video's on-screen counter (0:05–7:57).

This is the deepest teardown in the series — the cases come apart. It needs the flywheel puller set, a heat gun, and both grades of Loctite. The flywheel hub is single-use once heated, and the case bolts have to go back in the right order. Case and hub torque are 7 Nm.

Tools & supplies

• Flywheel hub holding tool + flywheel puller set (with backing "special tool")
• Torx T6 driver
• 4 mm Allen key
• Heat gun (or an oven for the case halves)
• Torque wrench (7 Nm)
• Green Loctite (hub-to-crankshaft mating surface), blue Loctite (hub bolt)
• Petroleum jelly / Vaseline (sealing O-rings)
• Cleaner or mineral spirits
• New flywheel hub, new bearings, new crankshaft oil seals, new sealing O-rings

Removal

1. 0:05 — Secure the flywheel hub with the holding tool and unscrew the flywheel retaining bolt from the crankshaft with a Torx T6.
2. 0:30 — Attach the flywheel puller. Set the special tool under the puller bolt, resting it against the crankshaft.
3. 0:37 — Tighten the puller down as far as it will go.
4. 0:51 — Heat the flywheel hub with the heat gun until it releases from the crankshaft, then draw it off with the puller. Do not reuse the flywheel hub — heating damages the magnets.
5. 1:25 — Remove the woodruff key. It can be reused if it isn't oxidized or rusty — clean it if needed.
6. 1:36 — Unscrew the five crankcase bolts with a 4 mm Allen key. The bolts are different lengths — note which position each came from.
7. 2:12 — Slightly split the case halves and lift the crankshaft out.
8. 2:20 — Clean the parts with cleaner or mineral spirits and remove the crankshaft oil seals.

Bearings

9. 2:20 — Heat the crankcase halves with a heat gun or in an oven — the old bearings should drop out easily. High burn risk.
10. 2:31 — Reheat the case halves and drop the new bearings in while hot — this is the easiest method. If you can't heat them, drive the bearings in with the special tool.
11. 2:55 — Check that every bearing is fully seated.

Installation

12. 4:37 — Fit the sealing O-rings into the crankcase grooves. Grease them with petroleum jelly to ease them in.
13. 5:24 — Insert the sleeves into the crankshaft cover.
14. 5:34 — Set the crankshaft into one case half, cover it with the other, and start the five bolts with a 4 mm Allen key.
15. 6:29 — The longer bolts go on the injector side.
16. 7:12 — Tighten the case bolts to 7 Nm.
17. 7:27 — Insert the woodruff key into the crankshaft.
18. 7:37 — Apply green Loctite to the mating surface between the flywheel hub and the crankshaft.
19. 7:57 — Fit the new hub and tighten it with the Torx T6 bolt and washer — always with blue Loctite on the bolt.