Author Topic: Hesketh V1200 Vulcan Front Cylinder Rattle  (Read 12 times)

David S

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Hesketh V1200 Vulcan Front Cylinder Rattle
« on: May 13, 2022, 03:38:52 PM »
Problem defined:-
•   Rattle when cold at about 1500 rpm.
•   Front cylinder only (rear cylinder runs fine).
•   Either side of 1500 rpm no rattle.
•   Rattle clears after warm up.

Changed front piston - rattle remains but at about 250rpm and louder this time.

Checks carried out and results:-
•   Oil flow to cams good
•   Cam chain set to correct tightness – no witness marks
•   No piston to cylinder head contact – no witness marks
•   No liner to big end bolt contact – no witness marks
•   No piston rock (slipper pistons) - no witness marks on liner or piston
•   Valve springs good – none broken, no binding
•   Tappets set and checked at between 0 and 1 thou” clearance
•   Piston to liner clearance = 4.7 thou
•   Bore parallel at 98.000mm throughout (piston spec = 98mm)
•   No big end play
•   Small end play – oval on RHS

Small End – could this be the problem?
•   Machined from both sides - detectable ridge 1/3rd in from LHS (this is normal apparently)
•   RHS oval – evidenced with pin part in - rocks in vertical plane

Other thoughts?
•   Is 4.7 thou” piston to liner clearance too big - bear in mind rear cylinder machined to same spec and doesn’t rattle

Otherwise it's a fabulous bike!

Appreciate suggestions for solutions or recommendation for further checks.