Quote:
Originally Posted by Jeff Higgins
The most dominant, all time winningest racing vehicle of any description (bike, car, airplane, boat, submarine, camel) in the history of this planet was a 45 degree V-Twin, with a better than 45 year record of near total domination unmatched by any other racing vehicle.
The 90 degree V-Twin, on the other hand, has some pretty serious packaging problems in a motorcycle chassis. The motor itself is fantastic. It does, however, reduce the "sum of the parts" to a lesser "whole". It forces the motor to be too far back, it forces the wheelbase to be too long. Both affect handling and acceleration to a very negative degree. Motorcycles are not just motors, and the motor planform has a much greater impact on other design and performance elements than just its power output.
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Flat track racing on dirt ovals is a tiny niche of the motorcycle racing world. Its like racing farm equipment in the motorcycle world. I can't think of anyone except for HD who makes a 45 twin and they only keep building them because of their legacy. When they start a clean sheet motor like the V-Rod and Pan America they have used 60 deg twins.
45 twins are tall, and the bigger the bores get the farther the pistons have to be from the crank axis. They're so tall that there isn't room for a sump under the crank so they need to go with a dry sump and that needs an oil tank somewhere and a more complex oil pump and plumbing.
Some Milwaukee 8s have sumping problems and thats just a lack of scavaging of the oil pump. I don't know how Harley let that slip past their development team.
Every manufacture has their issues but Harley seems to go the extra mile sometimes. They are the only bike I know where the dealer technician will fix a customers bike with a pair of bolt cutters.