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Originally Posted by afterburn 549
I did not understand I guess? I thought this thread was about the nuances , the romance, lunacy and archaicness of the V twinn
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This thread is about the multi piece harley crankshaft and its deficiencies. The problem lies with Harley wanting to keep the 45 deg v-twin. A 45 deg V makes for a tall engine and as motorcycles grow the displacement increases. With 45 deg V being so narrow, as the pistons get bigger they will start interfering with each other as they rotate. This requires longer rods to push the pistons away from each other and this makes the engine even taller. With a really tall engine there isn't room for an oil sump so Harley had to go with a dry sump oil system.
The multi piece crank tends to get out of true and when its gets bad enough the engine self destructs and your looking at replacing the entire engine. Some people are even taking the cranks apart to be straightened and welded. I wouldn't expect the welds to hold in the long run.
If you have a twin cam and you upgrade the cam drive from chains to gears, the problem gets worse much sooner. The chains can work with more misalignment than the gear drive.
Harley isn't alone in this kind of stupidity. There is a car manufactures out there who made an air cooled car and when the emmissions regs got tighter, they made the engine run hotter by reducing the number of fan blades and had some kind of thermal reactor in the exuast.
I may have one of these cars in my garage right now but the 5 bladed fan and reactors are long gone.