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[Jessee]

Why is some parts in cc ratings and others in inch size? I ordered piston rings for my 05 CVO with 103 engine. What I received was 1 (one) ring kit for 1 piston and it was for a 1550 cc engine. My manual says my 103 is 1690 cc. What engine size is the 1550? Why can't they stick to one description of engines...would definitely help me when I could receive the correct parts and not have to send back and reorder.

[kiwirob]

The 1690cc (103") and the 1550cc (95") have the same bore size. The difference in displacement is with the different stroke.- Rob

[GregKhougaz]

1 cubic centimeter =  0.0610237441 cubic inches

[Para Bellum]

My quick and dirty technique lets me remember the conversion: Ford's 302 CI engine is 5.0 liters, so 302 CI/ 5 L is approximately 60 CI in 1 liter.  Easy multiples: 2 liters = 120 CI.

[moscooter]

 
Yup,  it was indeed an increase in the stroke that created the stock 96 cubic inch engine.  With the "big bore" kit,  that engine becomes a 103.  The "big bore" cylinders used are the SAME cylinders that were used in prior years to turn a stock 88 cubic inch engine into a (big bore) 95.   An increase of 7 CI in either case.

[Dan_Lockwood]

Not that this is the case with the 103" and 95", keep in mind that in most automotive applications with longer stroke and the same bore, they move the wrist pin further up the piston to maintain the same "position" of the piston within the cylinder bore at TDC.

I think on HD's they lengthen the cylinders to compensate for the added stroke, but I'm not sure.

So in most cases the rings are the same as Don said, but "sometimes" with the same bore the wrist pin position in the piston may be different making it a special piston to that displacement bore/stroke combination.

Over the years at HD, they have made some pretty big changes in their piston designs.  A very good example of this is to compare a piston from my 74" Shovelhead and a new 110" CVO.  When I first saw a 110" piston in Rapid City Center at HD's display, I actually thought it was a cut down demo stuck to the board behind the counter.  The wrist pin it WAY up under the oil ring and the skirt is so short that it wouldn't be allowed in any high school dance...  This is part of the reason our 110" motors rattle like they do because there is not much linear support for the piston in the bore and they tend to rattle.

So much for my rambling again today...     

[dlaws01]

I think they sold you piston rings for a Kawasaki Vulcan or maybe a Yamaha V-Star.   

[prodrag1320]

Not that this is the case with the 103" and 95", keep in mind that in most automotive applications with longer stroke and the same bore, they move the wrist pin further up the piston to maintain the same "position" of the piston within the cylinder bore at TDC.

I think on HD's they lengthen the cylinders to compensate for the added stroke, but I'm not sure.

So in most cases the rings are the same as Don said, but "sometimes" with the same bore the wrist pin position in the piston may be different making it a special piston to that displacement bore/stroke combination.

Over the years at HD, they have made some pretty big changes in their piston designs.  A very good example of this is to compare a piston from my 74" Shovelhead and a new 110" CVO.  When I first saw a 110" piston in Rapid City Center at HD's display, I actually thought it was a cut down demo stuck to the board behind the counter.  The wrist pin it WAY up under the oil ring and the skirt is so short that it wouldn't be allowed in any high school dance...  This is part of the reason our 110" motors rattle like they do because there is not much linear support for the piston in the bore and they tend to rattle.

So much for my rambling again today...     

cylinders are the same for all 88,95,96 & 103 motors,the 95" & 103" are bored (3.750 88" & 96"/3.875 95" & 103")