is a brand-new quality product from the famous “Truett & Osborn” company for all 1937-73 Harley- Davidson 45” motors with 4-7/16" or larger stroker flywheels, for street or racing use. This is exactly what you need to complete your 45 stroker motor. The actual pistons are shown right, click the image for a larger version.
These pistons are a direct replacement (except for the stroke length adjustment to the compression distance and skirt length)
for the original pistons in all 45 motors. They are cast in low expansion aluminum alloy, and use the thinner, late model 45 & K ring set available anywhere.
The available pistons and rings are shown in the table below. You must specify the exact size you need. Sizes are based on std. = 2.745”. Sizes are nominal -.005” for skirt clearance. For example: a +.020” piston is actually 2.760” and requires a finish honed bore size of 2.765”, &c. Please measure your cylinders accurately, no refunds or exchanges will be made after purchase.
For ring sizes not available, the choices are:
1. Order the next larger pistons with rings.
2. Order your original size, but with .010” larger rings (for example: +.060” pistons with +.070” rings, etc.) so you can file the rings to get the correct end gap yourself.
3. Order your original size, but without rings, and purchase a ring set from another source. If you do this, deduct $20.00 from the price.
4. If you order a size we do not have, and do not respond to our email, your payment will be refunded.
Piston & ring sizes available
The pistons are suitable for flywheels with 4-7/16” (4.4375”), 4-1/2” (4.500”), 4-9/16” (4.5625”) and 4-5/8” (4.625”) strokes. For reference: the old-school Indian Chief flywheel is 4-7/16”, the H-D KH flywheel is 4-9/16”. I can supply stroker flywheels for most H-D engines 1937-*, click here for more information: .
You cannot use these pistons with stock flywheels or any stroke smaller than 4-7/16”. You cannot use these pistons with pop-up heads, such as 1948-52 WR, K or KH. You cannot use stock 45 pistons with stroker flywheels without modification. This is more complex than a normal rebuild, requiring prior experience and other assembly work. Victory does not install these parts.
Why should you buy these pistons from me, instead of somewhere else? Because I’m providing you with something extra that no one else does: a comprehensive, 10 page illustrated booklet with diagrams and dimensions to show you how to do this yourself, containing lots of useful information to help “talk you through” the process of installing them. Not sure you’re up to building this? Get the booklet first, it answers many questions.
The pistons are a “drop-in” fit with 4-7/16” flywheels (requiring no modifications to the pistons or engine, other than those required to install the flywheels themselves). The deck height at TDC is approximately std.; that is, the piston’s compression distance is 5/16” (.3125”) less than std., or approximately 1.23”. The skirt length clears the std. front cylinder crankcase baffle with this stroke. When used with larger strokes, the deck clearance will be less than std., requiring a small base shim, thicker head gasket, pop-up dome relief cut into the head’ gasket surface, etc. for proper clearance. Final deck height is the responsibility of your engine builder and must be set properly for safe and effective use of these pistons.
Click here to purchase this booklet for $5.00 by PayPal, sent to your e-mail address as a PDF file. This will be credited against your flywheel purchase: .
Note: these pistons may prove useful Indian 541 Junior Scout and 741/GDA military stroker engines. For more information, click here: .
ICTORY is the original source of side-valve performance since 1971.
Click here for a brief bio on the author: .
Payment & shipping instructions: please read carefully.
Price per set (1 pair): $145.00, plus postage.
The pistons will be shipped direct to your address by Priority Mail on receipt of payment from the U.S. manufacturer, complete with a full ring set and fitted piston pins & locks as shown, to save you freight in a strong box to insure safe delivery. There may (rarely) be a delay in shipment depending on production volume. You will be immediately notified if this occurs and offered a choice of waiting, an alternate oversize, or a full refund.
My address is below. Sorry, I can’t take your credit card directly, read below. All payments must be in US dollars, payable to Victory Library.
All foreign orders must include your local telephone number for our customs declaration.
Mail your postal or bank money order only,
please, (no personal or business checks) to:
515 Greengrove Avenue
Uniondale, NY 11553-2130 U.S.A.
Please include your e-mail address.
All other foreign
Use Visa or Mastercard to pay with PayPal
All payments must be in US dollars.
You must specify the piston size and your phone number
All other foreign countries
Due to the fees that PayPal charges me, a service charge is included in this purchase. This is less than it costs me to collect this money, and more convenient than your bank. If you prefer, use your local postal or bank money order.