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Engine & Performance

Choose from Engine & Performance products for Harley-Davidson, American V-twin and compatible motorcycle applications. Across the range you will find products for engine components. Compatibility varies, so match the stated model, year and technical details before ordering.

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£51.20
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£48.75
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£48.75

Cometic Cylinder Head Gasket Set. 3-5/8" .030" MLS – 1984–1999 Evo Big Twin; 1986–2005 XL…

Out of stock

Cometic Cylinder Head Gasket Set. 3-5/8" .030" MLS – 1984–1999 Evo Big Twin; 1986–2005 XL… .030" thick MLS (Multi Layer Steel). Consists of a top a...

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£51.20
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Cometic Cylinder Head. 3.5" Bore .040" MLS – 1984–1999 Big Twin; 1988–2022 XL…

Only 1 left!

Cometic Cylinder Head. 3.5" Bore .040" MLS – 1984–1999 Big Twin; 1988–2022 XL… .040" thick MLS (Multi Layer Steel). Consists of a top and bottom la...

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£48.75
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£51.20
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£48.75
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£48.75

Cometic Cylinder Head. 3.5" Bore .030" MLS – 1984–1999 Big Twin; 1988–2022 XL…

Only 2 left!

Cometic Cylinder Head. 3.5" Bore .030" MLS – 1984–1999 Big Twin; 1988–2022 XL… .030" thick MLS (Multi Layer Steel). Consists of a top and bottom la...

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£48.75
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£19.34
£19.34 - £19.34
£19.34
£18.42
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£18.42

Cometic Cylinder Base O-ring. FR/RR – 1999–2017 88" Up to 103" Twin Cam

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Cometic Cylinder Base O-ring. FR/RR – 1999–2017 88" Up to 103" Twin Cam Front & rear. All 3-3/4" (88"/96") & 3-7/8" (95"/103") bore applica...

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£19.34
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£18.42
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£18.42
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£51.20
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£48.75
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£48.75

Cometic Cylinder Head Gaskets 3-7/8" Bore .027" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore…

Out of stock

Cometic Cylinder Head Gaskets 3-7/8" Bore .027" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore… MLS (Multi Layer Steel). Front & rear gasket for on...

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£74.00
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£74.00
£71.44
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£71.44

Cometic Cylinder Head Gaskets 3-3/4" Bore .060" MLS – 1999–2017 88"/96" Twin Cam A/B

Only 2 left!

Cometic Cylinder Head Gaskets 3-3/4" Bore .060" MLS – 1999–2017 88"/96" Twin Cam A/B MLS (Multi Layer Steel). Front & rear gasket for one engin...

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£74.00
£71.44
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£71.44
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£74.00
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£74.00
£71.44
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£71.44

Cometic Cylinder Head Gaskets 3-7/8" Bore .060" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore…

Only 2 left!

Cometic Cylinder Head Gaskets 3-7/8" Bore .060" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore… MLS (Multi Layer Steel). Front & rear gasket for on...

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£74.00
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£74.00
£71.44
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£71.44
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£51.20
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£48.75
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£48.75

Cometic Cylinder Head Gaskets 4" Bore .040" MLS – 1999–2017 Twin Cam

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Cometic Cylinder Head Gaskets 4" Bore .040" MLS – 1999–2017 Twin Cam MLS (Multi Layer Steel). Front & rear gasket for one engine. 4.00" bore fi...

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£48.75
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£48.75
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£51.20
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£48.75
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£48.75

Cometic Cylinder Head Gaskets 4" Bore .030" MLS – 1999–2017 Twin Cam

Only 2 left!

Cometic Cylinder Head Gaskets 4" Bore .030" MLS – 1999–2017 Twin Cam MLS (Multi Layer Steel). Front & rear gasket for one engine. 4.00" bore fi...

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£51.20
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£51.20
£48.75
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£48.75
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£51.20
£51.20 - £51.20
£51.20
£48.75
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£48.75

Cometic Cylinder Head Gaskets 3-7/8" Bore .040" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore…

Only 2 left!

Cometic Cylinder Head Gaskets 3-7/8" Bore .040" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore… MLS (Multi Layer Steel). Front & rear gasket for on...

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£51.20
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£51.20
£48.75
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£48.75
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£51.20
£51.20 - £51.20
£51.20
£48.75
£48.75 - £48.75
£48.75

Cometic Cylinder Head Gaskets 3-7/8" Bore .030" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore…

Only 2 left!

Cometic Cylinder Head Gaskets 3-7/8" Bore .030" MLS – 1999–2017 Twin Cam. With 3-7/8" Bore… MLS (Multi Layer Steel). Front & rear gasket for on...

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£51.20
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£51.20
£48.75
£48.75 - £48.75
£48.75
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£51.20
£51.20 - £51.20
£51.20
£48.75
£48.75 - £48.75
£48.75

Cometic Cylinder Head Gaskets 3-3/4" Bore .040" MLS – 1999–2017 88"/96" Twin Cam A/B

Only 1 left!

Cometic Cylinder Head Gaskets 3-3/4" Bore .040" MLS – 1999–2017 88"/96" Twin Cam A/B MLS (Multi Layer Steel). Front & rear gasket for one engin...

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£51.20
£51.20 - £51.20
£51.20
£48.75
£48.75 - £48.75
£48.75
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£51.20
£51.20 - £51.20
£51.20
£48.75
£48.75 - £48.75
£48.75

Cometic Cylinder Head Gaskets 3-3/4" Bore .030" MLS – 1999–2017 88"/96" Twin Cam

Only 2 left!

Cometic Cylinder Head Gaskets 3-3/4" Bore .030" MLS – 1999–2017 88"/96" Twin Cam MLS (Multi Layer Steel). Front & rear gasket for one engine. O...

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£51.20
£51.20 - £51.20
£51.20
£48.75
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£48.75
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£4.91
£4.91 - £4.91
£4.91
£4.51
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£4.51

Cometic O-ring Breather Baffle – 1999–2010 Twin Cam

Only 2 left!

Cometic O-ring Breather Baffle – 1999–2010 Twin Cam 2 used. OEM replacement reference 11270. Fitment 99-10 Twin Cam (NU) Product Details Brand: C...

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£4.91
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£4.91
£4.51
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£4.51
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£11.95
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£11.95
£11.38
£11.38 - £11.38
£11.38

Cometic Gasket Breather Baffle – 1999–2010 Twin Cam

Only 2 left!

Cometic Gasket Breather Baffle – 1999–2010 Twin Cam .031" fiber. 2 used. OEM replacement reference 17592-99 Fitment 99-10 Twin Cam (NU) Product Det...

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£11.95
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£11.95
£11.38
£11.38 - £11.38
£11.38
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£17.53
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£17.53
£16.69
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£16.69

Cometic Filter Element, Breather Baffle – 1999–2010 Twin Cam

Only 2 left!

Cometic Filter Element, Breather Baffle – 1999–2010 Twin Cam Replaces OEM 63815-99. Fitment 99-10 Twin Cam (NU) Product Details Brand: Cometic C...

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£17.53
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£17.53
£16.69
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£16.69
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£44.59
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£44.59
£42.45
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£42.45

Cometic Umbrella Valve – 1999–2010 Twin Cam

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Cometic Umbrella Valve – 1999–2010 Twin Cam Rubber valve cover seal. For the head breathing system. Fitment 99-10 Twin Cam (NU) Product Details B...

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£44.59
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£44.59
£42.45
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£42.45
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£11.95
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£11.95
£11.38
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£11.38

Cometic Gaskets Breather Cover – 1999–2010 Twin Cam

Only 2 left!

Cometic Gaskets Breather Cover – 1999–2010 Twin Cam Fiber with a compressed thickness of .031". OEM replacement reference 17591-99 Fitment 99-10 Tw...

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£11.95
£11.95 - £11.95
£11.95
£11.38
£11.38 - £11.38
£11.38
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£87.46
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£87.46
£84.43
£84.43 - £84.43
£84.43

Cometic Gasket Lower Rocker Cover. RCS – 1999–2017 Twin Cam

Only 1 left!

Cometic Gasket Lower Rocker Cover. RCS – 1999–2017 Twin Cam .020" RCS (Rubber Coated Steel). 1-piece left/right gasket.; 2 used on one engine. OEM ...

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£87.46
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£87.46
£84.43
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£84.43
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£87.46
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£84.43
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£84.43

Cometic Gasket Rocker Cover. Upper. RCS – 1999–2017 Twin Cam

Only 2 left!

Cometic Gasket Rocker Cover. Upper. RCS – 1999–2017 Twin Cam .020" RCS (Rubber Coated Steel). OEM replacement reference 17386-99; 17386-99A Fitment...

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£87.46
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£87.46
£84.43
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£84.43
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£21.56
£21.56 - £21.56
£21.56
£20.53
£20.53 - £20.53
£20.53

Cometic Cam Gear Change Gasket Kit – 1993–1999 Big Twin

Out of stock

Cometic Cam Gear Change Gasket Kit – 1993–1999 Big Twin Paper gaskets. Complete with all gaskets and seals you need when the camshaft is replaced. ...

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£21.56
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£21.56
£20.53
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£20.53
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£26.69
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£26.69
£25.42
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£25.42

Cometic Cam Gear Change Gasket Kit. 70-92 B.T – 1970–1992 Big Twin

Out of stock

Cometic Cam Gear Change Gasket Kit. 70-92 B.T – 1970–1992 Big Twin Paper. Complete with all gaskets and seals you need when the camshaft is replace...

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£26.69
£26.69 - £26.69
£26.69
£25.42
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£25.42
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£61.64
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£61.64
£58.69
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£58.69

Cometic Cam Gear Change Gasket & Seal Kit – 1999–2017 Twin Cam

Out of stock

Cometic Cam Gear Change Gasket & Seal Kit – 1999–2017 Twin Cam Complete with all gear cover & rocker box cover gaskets and seals you need w...

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£61.64
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£61.64
£58.69
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£58.69
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£39.24
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£39.24
£37.36
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£37.36

Cometic 5-Speed Transmission Gasket & Seal Kit – 1999–2005 Twin Cam Dyna

Out of stock

Cometic 5-Speed Transmission Gasket & Seal Kit – 1999–2005 Twin Cam Dyna Everything you need when assembling the transmission. Fitment 99-05 Tw...

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£39.24
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£39.24
£37.36
£37.36 - £37.36
£37.36
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