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Stock Replacement Pistons
for 61 cui Models 1915-1923
for 61 cui Models 1915-1923
If you look up old parts manuals, you won't find oversize pistons for the IOE models. Replacing a piston wasn't an easy thing then as Harley-Davidson from 1914 on equipped all pocket-valve engines with conically bored and honed cylinders and cylindric pistons. Of course, oversized pistons were available to dealers, but boring a cylinder was a task that one would maybe like to leave to the factory — and of course the factory offered this service. <br />The then used piston types nowadays not being readily available nor the friendly factory service being offered any more, our range comprises modern oval shaped high strength and highly heat-resistant pistons that are forged from 2618 aluminum and heat treated to T61. <strong>As with all modern pistons the cylinders must be cylindrically bored.</strong> The 30° piston dome will give you about 6:1 compression ratio but may be machined to lower compression to 4.5:1 stock compression rate. .003” clearance — as indicated on the piston packaging — is a good starting point for engines that are low compression, subject to moderate loads and that are broken in carefully. Heavily working higher compression engines may nevertheless require up to .008”.
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for 74 cui Models 1921-1929
for 74 cui Models 1921-1929
If you look up old parts manuals, you won't find oversize pistons for the IOE models. Replacing a piston wasn't an easy thing then as Harley-Davidson from 1914 on equipped all pocket-valve engines with conically bored and honed cylinders and cylindric pistons. Of course, oversized pistons were available to dealers, but boring a cylinder was a task that one would maybe like to leave to the factory — and of course the factory offered this service. <br />The then used piston types nowadays not being readily available nor the friendly factory service being offered any more, our range comprises modern oval shaped high strength and highly heat-resistant pistons that are forged from 2618 aluminum and heat treated to T61. <strong>As with all modern pistons the cylinders must be cylindrically bored.</strong> The 30° piston dome will give you about 6:1 compression ratio but may be machined to lower compression to 4.5:1 stock compression rate. .003” clearance — as indicated on the piston packaging — is a good starting point for engines that are low compression, subject to moderate loads and that are broken in carefully. Heavily working higher compression engines may nevertheless require up to .008”.
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for Flatheads 750cc 1929-1973
for Flatheads 750cc 1929-1973
All OEM and identical aftermarket pistons for 45”/750 cc models 1929→ (except WR) have the same compression height. Different compression ratios are achived solely with different cylinder heads for the respective model group like D, R, W, WL, WLD, WLA etc. These range from 4.3:1 to 6.0:1.
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for Flatheads 1200/1300cc 1930-1936 and Flatheads 1300cc 1937-1941
for Flatheads 1200/1300cc 1930-1936 and Flatheads 1300cc 1937-1941

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for Flatheads 1200cc 1937-1948
for Flatheads 1200cc 1937-1948

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for Knucklehead and Panhead 1000cc
for Knucklehead and Panhead 1000cc

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for Knucklehead, Panhead and Shovelhead 1200cc
for Knucklehead, Panhead and Shovelhead 1200cc

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for Shovelhead 1340cc
for Shovelhead 1340cc

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for Evolution Big Twin 1340cc
for Evolution Big Twin 1340cc

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for Sportster 900cc, 1957-1971
for Sportster 900cc, 1957-1971

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for Sportster 1000cc, 1972-1985
for Sportster 1000cc, 1972-1985

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for Sportster 883cc Evolution 1986-2003
for Sportster 883cc Evolution 1986-2003

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for Sportster 1200cc Evolution 1988-2003, Buell Models 1995-1998
for Sportster 1200cc Evolution 1988-2003, Buell Models 1995-1998

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Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: service@wwag.com